Keywords: POSTPONEMENT, MASS CUSTOMIZATION third-party logistics, case study-based research form postponement, delayed product differentiation, third-party logistics, mass customisation, case study-based research

Third-party logistics providers offering form postponement services: value propositions and organisational approaches

Introduction

Form postponement is an operations design principle that more and more companies today are turning to [START_REF] Matthews | The power of postponement[END_REF] under the effect of increasing product variety and customisation [START_REF] Pine | Mass Customization -The New Frontier in Business Competition[END_REF][START_REF] Bayus | Product proliferation: an empirical analysis of product line determinants and market outcomes[END_REF][START_REF] Funke | Product variety and economic growth: empirical evidence from the OECD countries[END_REF]. The principle of form postponement (FP) proposes that companies defer their commitment of resources to a specific end-product in the manufacturing and distribution process as long as possible [START_REF] Alderson | Marketing efficiency and the principle of postponement[END_REF][START_REF] Heskett | Logistics -essential to strategy[END_REF]. Application of FP requires deferring at least one product differentiation activity (PDA), which specialises the work-in-progress into particular end-products, and the decision driving such activity [START_REF] Lee | Effective inventory and service management through product and process redesign[END_REF][START_REF] Garg | On postponement strategies for product families with multiple points of differentiation[END_REF]. By deferring a PDA, FP allows for the collecting of new information about customer demands (e.g., actual customer orders, or updated sales forecasts in case of make-to-stock production) prior to the making of the decision driving the PDA, thereby reducing uncertainty (Yang et al. 2004a[START_REF] Forza | Form postponement effects on operational performance: a typological theory[END_REF][START_REF] Wong | Analysis of form postponement based on optimal positioning of the differentiation point and stocking decisions[END_REF].

Third-party logistics providers (3PLs) can play an important role in FP implementation (van Hoek 2000a, [START_REF] Yang | Postponement: an inter-organizational perspective[END_REF], owing to the increasing geographical dispersion of supply chains. As production moves farther away from primary markets, there is a greater incentive to implementing FP by placing PDAs in the distribution channel. By doing so, companies serving global markets avoid making decisions on final product configurations far ahead of the moment of customer purchase and assure high responsiveness, while retaining scale economies at centralised factories [START_REF] Cooper | Logistics strategies for global businesses[END_REF][START_REF] Van Hoek | Reconfiguring the supply chain to implement postponed manufacturing[END_REF]. With more and more companies trying to place PDAs in the distribution channel, it comes as no surprise that 3PLs, especially large 3PLs operating on a continental or even global scale, see the carrying out of PDAs on behalf of manufacturing companies as a viable extension of their service offerings (van Hoek 2000a). By doing so, 3PLs can raise turnover in a higher-margin area of the supply chain than the increasingly commodified traditional logistics services (van Hoek 2000b). Moreover, by supplementing transport-and warehousing-based services with the carrying out of PDAs in the distribution channel, 3PLs can reap the benefits of deeper relations with existing customers and increased customer loyalty (van Hoek 2000a).

While both the literature on FP (van Hoek 2001, Yang et al. 2004b) and the literature on third-party logistics [START_REF] Selviaridis | Third party logistics: a literature review and research agenda[END_REF]Spring 2007, Marasco 2008) have rapidly grown over the last few years, less attention has been paid so far to FP supported by 3PLs. The present paper aims to augment our understanding of how 3PLs can deliver value to companies offering product variety by providing FP services, defined as the carrying out of PDAs on behalf of these companies close to the target markets. Accordingly, the paper empirically investigates the following two research questions: What FP services can a 3PL offer and how do they create value for the customer buying the service? Moreover, what organisational solutions can a 3PL adopt to provide an FP service, how do they influence value to the 3PL's customer, and what are the associated challenges for the 3PL?

The remainder of this paper is organised as follows. Section 2 provides motivations for our research in the context of the existing literature on FP. Section 3 describes and justifies the inductive research design we used to address our research questions. Three observations linking 3PL-provided FP services, value to the 3PL's customer, organisational approaches, and enabling or hindrance factors are presented, along with the evidence supporting each observation, in Section 4. Section 5 concludes by discussing the contribution of this study to the FP literature, the managerial implications of our findings, as well as their limitations and associated opportunities for future research.

Background

The notion of FP first appeared in literature in the 1950s, when [START_REF] Alderson | Marketing efficiency and the principle of postponement[END_REF][START_REF] Alderson | The strategic perils of delayed differentiation[END_REF] proposed postponement in product differentiation as a principle to improve the efficiency of a production and distribution system. Product differentiation may occur in product form and identity, thereby resulting in different varieties, or in product location, thus leading to geographical dispersion of inventories. Postponement of changes in product form and identity has been subsequently termed in literature as FP, delayed product differentiation, late customisation, manufacturing postponement, or simply postponement [START_REF] Swaminathan | Design for postponement[END_REF]Lee 2003, Forza et al. 2008). On the other hand, postponement of changes in inventory location has been later called logistics postponement, delayed geographic differentiation, place postponement, or time postponement [START_REF] Pagh | Supply chain postponement and speculation strategies: how to choose the right strategy[END_REF]Cooper 1998, Aviv and[START_REF] Aviv | Design for postponement: a comprehensive characterization of its benefits under unknown demand distributions[END_REF].

The majority of extant literature addresses FP on a single company level [START_REF] Yeung | Postponement strategy from a supply chain perspective: cases from China[END_REF]. From such a perspective, many studies have researched FP antecedents, focusing on market characteristics, product characteristics, and production process characteristics that influence FP (Yang et al. 2004b). Market characteristics promoting FP include factors such as a high number of product variants (Zinn 1990, Johnson and[START_REF] Johnson | Postponement strategies for channel derivatives[END_REF], high uncertainty and [START_REF] Zinn | Developing heuristics to estimate the impact of postponement on safety stock[END_REF]Bowersox 1988, Aviv and[START_REF] Aviv | Design for postponement: a comprehensive characterization of its benefits under unknown demand distributions[END_REF], and short product life cycles (van Hoek et al. 1998[START_REF] Chiou | The adoption of form postponement strategy in a global logistics system: the case of Taiwanese information technology industry[END_REF]. In turn, product characteristics favouring FP encompass high product value [START_REF] Zinn | Developing heuristics to estimate the impact of postponement on safety stock[END_REF]Bowersox 1988, Chiou et al. 2002), high product modularity [START_REF] Lee | Effective inventory and service management through product and process redesign[END_REF]Tang 1997, Yang et al. 2004a), and high component standardisation (Lee 1996, Harrison and[START_REF] Harrison | Implications of form postponement to manufacturing: a cross case comparison[END_REF]. Finally, production process characteristics facilitating FP comprise low capital intensity and no need for special capabilities at the postponed PDA (van Hoek 1997, Pagh and[START_REF] Pagh | Supply chain postponement and speculation strategies: how to choose the right strategy[END_REF], high process modularity [START_REF] Feitzinger | Mass customization at Hewlett-Packard: the power of postponement[END_REF]Lee 1997, Swaminathan and[START_REF] Swaminathan | Design for postponement[END_REF], and availability of substantial excess capacity at the deferred activity (Gupta andBenjaafar 2004, Harrison and[START_REF] Harrison | Implications of form postponement to manufacturing: a cross case comparison[END_REF].

Similarly, from a single company's perspective many studies have researched FP consequences, focusing on FP operational outcomes rather than on its strategic implications [START_REF] Alderson | The strategic perils of delayed differentiation[END_REF]. For a detailed discussion of previous research findings on FP effects on six performance dimensions (i.e., inventory-holding costs, delivery lead-times, processing costs, transport costs, order specification flexibility, and quality conformance), we refer to [START_REF] Forza | Form postponement effects on operational performance: a typological theory[END_REF]. They distinguish three mutually exclusive and exhaustive types of FP at the company level of analysis: From-forecast-to-order-driven FP, Remaining-forecast-driven FP and Remaining-order-driven FP. Further, they show that the effects of FP on a given performance dimension and/or the mechanisms explaining such effects often vary according to the type of FP that is being considered. Notably, a few of these effects and mechanisms, such as lower transport costs due to the changed nature of the items shipped to distribution centres or higher processing costs owing to fixed asset duplication at distribution centres, are specific to the situation in which a PDA is moved into the distribution channel [START_REF] Zinn | Developing heuristics to estimate the impact of postponement on safety stock[END_REF]Bowersox 1988, Lee and[START_REF] Lee | Designing products and processes for postponement[END_REF].

Less research has been devoted to examining FP from an inter-organisational perspective (van Hoek 2001, [START_REF] Yeung | Postponement strategy from a supply chain perspective: cases from China[END_REF]. A few studies address this topic at the whole supply chain level of analysis. [START_REF] Yang | Implications of postponement for the supply chain[END_REF] argue that postponement in general, including FP, requires that uncertainties in the supply chain be reduced as much as possible through internal and external integration. Such an argument is supported by a subsequent exploratory survey conducted by Yang et al. (2005a), who find that most of the highest ranked barriers to postponement were related to how a company manages its external networks (both suppliers and customers). [START_REF] Yang | Postponement: an inter-organizational perspective[END_REF] further highlight the importance of choosing appropriate interorganisational structures to successfully implement postponement. In turn, [START_REF] Yeung | Postponement strategy from a supply chain perspective: cases from China[END_REF] investigate how one company's postponement decision is affected by the company's degree of external integration and by the market structure in both the upstream and downstream parts of the company's supply chain. Finally, building on [START_REF] Bucklin | Postponement, speculation and the structure of distribution channels[END_REF] seminal work on the combined principle of postponement and speculation, García-Dastugue and Lambert (2007) show that when one organisation implements postponement without considering its impact on the other supply chain members, inventory-holding costs for the supply chain as a whole may turn out to be higher.

Other studies researching FP from an inter-organisational perspective focus on either the upstream or the downstream part of a company's supply chain. Examining the upstream part, [START_REF] Prasad | Build to order supply chains in developed and developing countries[END_REF] find that close integration with suppliers is essential to prevent FP from impairing product delivery lead-times. In turn, [START_REF] Kumar | A manufacturing decision framework for minimizing inventory costs of a configurable off-shored product using postponement[END_REF] show that when manufacturing operations are moved to overseas suppliers, FP can help minimise the inventory cost impact of increased lead-times. Looking at next-tier customers, however, Krajewsky et al. 5 frequency of the changes that customers are allowed to make to order quantities. In turn, [START_REF] Brown | Xilinx improves its semiconductor supply chain using product and process postponement[END_REF] and [START_REF] Davila | An empirical test of inventory, service and cost benefits from a postponement strategy[END_REF] investigate the operational benefits of implementing FP by transferring PDAs to customers. Finally, two survey-based studies focus on the role of 3PLs in implementing FP by moving PDAs into the distribution channel. [START_REF] Van Hoek | Postponed manufacturing supplementary to transportation services?[END_REF] and van Hoek (2000a) find that 3PLs were mostly involved in relatively simple PDAs, such as packaging and labelling, and that 3PL involvement in FP implementation was expected to grow in the years to come. Moreover, van Hoek's (2000a) results indicate that a higher rate of engagement of 3PLs in FP implementation was associated with the use of integration mechanisms such as account management and comprehensive performance measurement systems covering production and customisation activities.

In summary, our review of the FP literature indicates that while the carrying out of postponed PDAs in the distribution channel has been widely discussed (e.g., [START_REF] Lee | Hewlett-Packard gains control of inventory and service through design for localization[END_REF][START_REF] Twede | Packaging postponement: a global packaging strategy[END_REF][START_REF] Shao | Evaluation of postponement strategies in mass customization with service guarantees[END_REF], less attention has been paid to examining such an FP strategy when it involves other supply chain members than the manufacturing company. In particular, while the possibility of outsourcing PDAs placed in the distribution channel to 3PLs has been well documented in the FP literature (e.g., van Hoek 2000a[START_REF] Yang | Implications of postponement for the supply chain[END_REF][START_REF] Yang | Postponement: an inter-organizational perspective[END_REF], research on the contribution that a 3PL can make to a company's FP strategy is still in its infancy.

Research objectives and method

This study aims to contribute to a better understanding of how 3PLs can deliver value to companies offering product variety by providing FP services, defined as the carrying out of PDAs on behalf these companies close to the target markets. More specifically, our study addresses the following research questions:

RQ1. What FP services can a 3PL offer and how do they create value for the customer buying the service? RQ2. What organisational solutions can a 3PL adopt to provide an FP service, how do they influence value to the 3PL's customer, and what are the associated challenges for the 3PL?

Owing to the lack of research examining these questions, our inquiry employed a case study approach [START_REF] Yin | Case study research: design and methods[END_REF][START_REF] Eisenhardt | Building Theories from Case Study Research[END_REF]). When little is known, the richness and detail of qualitative data are crucial in identifying key constructs relevant to explaining the focal phenomenon [START_REF] Patton | Qualitative evaluation and research methods[END_REF]. In addition, qualitative data are particularly useful for examining "how" and "why" questions [START_REF] Yin | Case study research: design and methods[END_REF], and understanding how and why FP services create value for the 3PL's customer and how and why FP service organisational solutions influence such value was one of the fundamental aims of our research.

The unit of analysis, in this exploratory study, was a product-customer combination-namely a given product type of a given customer-for which a 3PL carries out at least one PDA on behalf of the customer. This is an appropriate unit of analysis, as FP applies to a product that is made in at least two different variants sharing the same basic functionalities and common manufacturing activities [START_REF] Garg | On postponement strategies for product families with multiple points of differentiation[END_REF]Tang 1997, Gupta and[START_REF] Gupta | Product family-based assembly sequence design methodology[END_REF]. Accordingly, those product-customer combinations for which the 3PL performs transformational activities that do not create product variety (e.g., ironing cloths shipped in bulk from overseas factories) were excluded from the reference population. Cases were chosen from among the product-customer combinations served by one of the world's leading logistics groups, which provides both traditional logistics services and valueadded services (VASs) through an international network linking more than 200 countries and territories worldwide. This 3PL presented an interesting context for our research for two reasons. First, the 3PL was supplying a broad range of FP services to several product-customer combinations under a variety of labels, such as postponement, contract assembly, kitting, copacking, etc. 1 Secondly, the 3PL was interested in better understanding both the mechanisms through which FP services can create customer value and the challenges in improving such services. To increase the likelihood of observing different types of FP service and different types of FP service organisational solution, we selected cases from different industries or, if an industry is the same, from different types of product (Table 1).

Insert Table 1 Data were collected in two rounds partially overlapping with data analysis to take advantage of flexible data collection [START_REF] Eisenhardt | Building Theories from Case Study Research[END_REF]. During the first round, we gathered information according to a semi-structured research protocol covering the following areas: customer profile, product family profile, supply chain configuration, facility profile, postponed PDA characteristics, FP service outcomes, FP service enablers, and FP service obstacles. To probe particular themes emerging from first-round data analysis, in the second round of data collection we added one case (i.e., case 6) and adjusted the research protocol to gather additional information on the role of resource-sharing in the provision of FP services. In particular, we defined a comprehensive list of resources that a 3PL may use in serving a product-customer combination, which list covers the following resource categories: facility, equipment, workforce, information technology (IT) system, transport, administrative staff, licences and other services. Based on this list, for each case we gathered information on whether and which resources were systematically shared with other product-customer combinations, as well as information on the characteristics of the product-customer combinations among which resources were shared.

Data were collected from three main sources: open-ended interviews, archival documents, and direct observations. Each case involved at least one visit to the 3PL site where the productcustomer combination was served. Furthermore, we conducted in-depth interviews with middleand upper-level managers in charge of the whole site or the specific FP service within the site. To reduce observer bias [START_REF] Voss | Case research in operations management[END_REF] and simultaneously enhance the creative potential of the study [START_REF] Eisenhardt | Building Theories from Case Study Research[END_REF]), 70% of the in-depth interviews were conducted by two investigators. Additional primary data were collected through shorter interviews with 3PL executives in charge of business development in the industries from which the cases had been selected. Finally, primary information obtained from manager interviews and site visits were supplemented with secondary data from archival documents collected before and after the visit, such as responses to requests for quotation and internal presentations.

1. The exact number of product-customer combinations that the 3PL provides FP services is not available. This is because, within the 3PL organization, FP services often go under the same labels as other contract manufacturing services that do not involve execution of PDAs. During our preliminary check of the 3PL's FP services in Europe, the 3PL informed us about 32 cases that, in the company's opinion, were relevant to our research. After careful examination, however, we ascertained that only 18 out of these 32 cases were undoubtedly cases of FP. Data analysis consisted of two steps, namely within-case analysis and cross-case analysis. Following [START_REF] Eisenhardt | Building Theories from Case Study Research[END_REF] suggestions, within-case analysis involved writing detailed descriptions of the selected cases in order to become intimately familiar with each case as a stand-alone entity. Additionally, open and axial coding techniques [START_REF] Strauss | Qualitative analysis for social scientists[END_REF] were used to reduce qualitative data and identify the main themes and variables relevant to the research questions. In the subsequent phase of cross-case analysis, we compared and classified the selected cases according to the related supply chain configurations before and after FP service implementation and according to the resource-sharing profile observed in each case. Moreover, variable-oriented comparisons were made through comparative matrices to highlight patterns. The insights generated from cross-case analysis were finally submitted to the criticism of informants and other 3PL executives in order to check the correctness of our interpretation and discuss generalisability of our findings.

Results

Form postponement services and their value propositions

The data from this research indicate that a 3PL may provide different types of FP service, which have the potential to create value for the 3PL's customer through different mechanisms. The empirical evidence on the FP services supplied in the selected cases and on the value delivered to the 3PL customer is summarised in Table 2. Moreover, pictorial representations of the offered FP services are provided in Figures 1234.

Insert Table 2 A first type of FP service comprises those situations in which the service provider takes on responsibility for creating product variants that the 3PL's customer used to produce upstream in the supply chain. Stated otherwise, this type of FP service applies to existing PDAs, which create product variants for geographical markets that the 3PL's customers were already serving. Accordingly, we refer to this type of FP service as an existing-PDA FP service. The 3PL's customers may take advantage of this type of FP service to improve their operational and financial performance in supplying their existing geographical markets, as shown by cases 1-4.

In case 2, an originally forecast-driven PDA ends up being carried out on a to-order basis (Figure 1). Accordingly, this existing-PDA FP service may be classified in Forza et al.'s (2008) terms as a from-forecast-to-order-driven-PDA FP service. A fundamental benefit, in this case, is that the FP service enables order-driven execution of PDAs without excessive increase of delivery lead-time. The manufacturer no longer incurs the risks and associated costs of inaccurately forecasting the demand mix relative to the varieties created by the postponed PDA. Furthermore, the increase of delivery lead-time due to elimination of finished goods speculative stock is alleviated as compared to the situation in which the PDA were performed on a to-order basis at a site farther away from the target markets. Case 2 also indicates financial benefits of this FP service, as the manufacturer need not invest in setting up a facility to create varieties based on customer orders close to the target markets. Finally, there are other financial and operational advantages, such as reduced overhead and increased volume flexibility, that are contingent on the specific organisational approach adopted by the 3PL to provide the service and are, therefore, discussed in Section 4.2.

Insert Figure In cases 1 and 4, an originally forecast-driven PDA continues to be carried out on a toforecast basis after FP service implementation (Figure 2). Accordingly, this existing-PDA FP service may be classified in Forza et al.'s (2008) terms as a remaining-forecast-driven-PDA FP service. A fundamental benefit, in this case, is that the FP service enables the manufacturer to reduce finished goods inventory-holding and shortage costs without sacrificing on-hand availability of end-products. The postponed PDA is performed close to the target markets and, hence, the forecast window associated with this activity is shorter and the related forecast is more accurate. Furthermore, lead-times in responding to unanticipated market requirements are shorter. Common to both case 1 and case 4 is also the financial benefit of reduced investment in fixed assets, as compared to the situation in which the manufacturer itself sets up a facility to carry out the PDA close to the target markets. Finally, other financial and operational advantages of this FP service, such as the reduced transport costs and lower overhead observed in either case 1 or case 4, depend on the specific PDA to which the service is applied or the specific organisational approach adopted by the 3PL to supply the service.

Insert Figure 2 In case 3, finally, an originally order-driven PDA continues to be executed on a to-order basis after FP service implementation (Figure 3). Accordingly, this existing-PDA FP service may be classified in Forza et al.'s (2008) terms as a remaining-order-driven-PDA FP service. A fundamental benefit, in this case, is that the FP service enables the manufacturer to improve customer service through greater order specification flexibility. The manufacturer's customers have more time to make their decisions on the product feature(s) added by the postponed PDA without time and cost performance being worsened, as the PDA is carried out later in the order fulfilment process. Case 3 also indicates financial benefits of this FP service, as the manufacturer need not invest in setting up a facility to perform the PDA close to the target markets. Finally, there are other financial and operational advantages, such as reduced overhead and distribution costs, that are contingent on the specific organisational approach adopted by the 3PL to provide this FP service.

Insert Figure 3 When we analyse the FP services supplied in cases 5-7, however, a different value-creating mechanism emerges. In all these cases, the fundamental benefit of the provided service is to enable the 3PL's customer to enter and profitably serve new geographical markets. Supplying such new markets requires creating new product variants, but the 3PL's customer could not profitably make these varieties in-house. It might be too costly for the 3PL's customer to ensure service levels in line with incumbents by creating these varieties at its factory, while the investment needed to set up a facility to perform the PDA close to the target markets might be excessively high (see case 7). Alternatively, the 3PL's customer might be a service company or a fabless company that would not find it advantageous to set up a facility and develop manufacturing competences to carry out the PDA in-house (see cases 5 and 6). In any case, the 3PL's network of facilities enables the 3PL's customer to create the product variants needed to address the new target markets in a profitable manner. Not only is the initial investment minimised, but also operational performance is improved by virtue of the product variants being created close to the target markets. Additionally, further benefits, such as the reduced overhead and operating costs observed in cases 6 and 7, arise from the specific organisational approach adopted by the 3PL to provide the service.

In cases 5-7, in short, the FP service applies to a PDA that the 3PL's customer could not profitably carry out, and results in the 3PL performing the PDA in the distribution channel, close to the new target markets (Figure 4). Accordingly, we refer to this type of FP service as a PDAenabling FP service. Involving a new PDA, rather than an existing one, this type of FP service cannot be mapped onto the FP types defined by [START_REF] Forza | Form postponement effects on operational performance: a typological theory[END_REF].

Insert Figure 4 Based on the cross-case analysis, the following observation concerning FP services and their value propositions can be made: Observation 1. FP services have the potential to create value for the 3PL's customer either by improving operational and financial performance in serving existing geographical markets (existing-PDA FP services) or by enabling entry into new geographical markets (PDA-enabling FP services).

While our empirical inquiry has focused on the mechanisms through which FP services can create value for the company buying the service, it is important to acknowledge the possible drawbacks of using FP services from the 3PL's customer perspective. When a PDA is moved into the distribution channel, processing costs may increase because labour and equipment required by the postponed activity need to be duplicated at multiple distribution sites. Additional costs are also incurred to pack and unpack the semi-finished products shipped from the manufacturing plant to the distribution sites where finished product variants are created. Furthermore, if the postponed PDA is carried out in the distribution channel on a to-order basis, processing costs may rise due to the loss of manufacturing scale economies at the postponed activity or because of the need for keeping excess capacity at distribution sites to enable quick response to demand peaks. Use of an FP service may also lead to higher quality assurance costs, if the level of training and experience of the people responsible for PDA execution in the distribution channel is lower than at the manufacturing plant. Other possible disadvantages of FP services include higher finished goods distribution costs and longer delivery lead-times. When the postponed PDA is carried out in the distribution channel on a to-order basis, logistics scale economies are lost, owing to direct deliveries to customers, and the work content of the order fulfilment process increases, as end-products are no longer available on-hand. Interestingly, some of the abovementioned drawbacks of using FP services can be mitigated if 3PLs succeed in supplying such services through appropriate organisational solutions, as we will discussed hereinafter.

Form postponement service organisational approaches, effects on customer value and implementation challenges

The data from this research indicate that different organisational approaches may be used to provide an FP service to a given product-customer combination, with different effects on the value delivered to the 3PL's customer. The empirical evidence on the organisational solutions adopted in the selected cases, their impact on customer value and the associated challenges for the 3PL is summarised in Table 3. Pictorial representations of the adopted organisational solutions are also provided in Figure 5.

Insert Table 3 Insert Figure 5 One fundamental approach to supplying an FP service to a given product-customer combination is to use resources dedicated to that combination: namely, an ad-hoc facility. This ad-hoc approach is illustrated by cases 1, 4 and 5, in which all, or almost all, the resources employed to provide the service are dedicated to a single product-customer combination.

The alternative approach to supplying an FP service consists of using a platform, defined as a collection of resources systematically shared by a set of product-customer combinations. This platform approach is common to cases 2, 3, 6 and 7. When we compare these cases, however, different solutions emerge under the same "platform" label. In cases 2 and 3, resources are shared within a single facility among different product families of the same customer and, therefore, we refer to such a solution as a multi-product platform. Resource-sharing occurs within a single facility in case 6 as well, but involves different customers with similar products. Accordingly, such a solution will hereafter be labelled as a multi-customer platform. In case 7, finally, resources are also shared between distinct facilities located in close proximity to each other and, hence, we refer to such a solution as a campus-style platform.

The data collected in this study also indicate that in the supplying of an FP service, the platform approach has the potential to create more value for the 3PL's customer than the ad-hoc approach. All the cases in which the ad-hoc approach is adopted exhibit problems of capacity underutilisation, especially where demand fluctuations are wider because of strong seasonal peaks (cases 4 and 5). Conversely, capacity utilisation increases in all cases in which the platform approach is used, even where promotions lead to high demand variability (case 6). This is because fixed assets are systematically shared among multiple product-customer combinations. Consequently, fewer resources are needed to serve each of these combinations and, hence, unit processing costs are lower.

Besides increasing fixed asset productivity, the platform approach tends to reduce dependence on temporary labour without sacrificing volume flexibility. All the cases in which an ad-hoc facility is used exhibit heavy reliance on temporary labour as a means of coping with demand peaks that are often strong and unpredictable. In case 5, for example, sometimes the 3PL has to quadruple production volume from one week to the next because of a promotion. However, the 3PL does not receive any prior information from its customer, who is concerned about possible dissemination of confidential promotion-related information among competitors. Heavy dependence on temporary labour may limit responsiveness, as this type of workforce may be difficult to find in the local market, especially at certain times of year such as just before Christmas (case 5). Additionally, strong dependence on temporary labour may lead to higher costs because of production losses owing to worker inexperience (case 5) and because of the need for multiple checks in the production lines to assure quality (case 1). On the contrary, the cases in which the platform approach is adopted show a lower dependence on temporary labour even though the postponed PDA is always labour-intensive and demand variability is sometimes high. In case 6, for example, requirements for additional workforce at a given product-customer combination are usually met through sharing of permanent staff with the other product-customer combinations served by the platform. In this case, the 3PL hires temporary workers only in July, when demand peaks for the product-customer combinations served by the platform overlap. Notably, not only is volume flexibility preserved, but may even improve, especially when longer training is needed to perform the PDA (case 6) and temporary workers are more difficult to find in the local market (case 2). This is because momentary excess capacity at one productcustomer combination can be quickly diverted to another product-customer combination where capacity is insufficient, without the need for additional training.

Finally, using the platform approach in the provision of an FP service may increase customer value by reducing costs in the distribution of the product variants created by the postponed PDA. In cases 2, 3 and 7, distribution costs are lower because the product-customer combinations served by each of these platforms have partially overlapping delivery points and are distributed by the same 3PL. As product-customer combinations with overlapping delivery points are served within the same facility or group of facilities located close to each other, loading points overlap as well. Consequently, shipments of finished goods may be consolidated, if the company in charge of distribution is the same.

Integrating the above arguments concerning platform approach advantages in terms of fixed asset utilisation, dependence on temporary labour, volume flexibility, and distribution costs, we make the following observation:

Observation 2. In the supplying of an FP service, the platform approach has the potential to create more value for the 3PL's customer than the ad-hoc approach.

This observation focuses on the potential benefits of the platform approach. Many factors, however, influence both the possibility and the cost of systematically sharing resources among a given set of product-customer combinations without impairing responsiveness. The data from this research indicate a number of factors that enable or hinder resource-sharing among productcustomer combinations served within the same facility or the same group of facilities located close to each other. Implementing such enabling factors and minimising such hindrance factors represent just as many challenges that a 3PL will face in applying the platform approach. As witnessed by case 1, in which only a few resources such as general site management, licences, security service and other auxiliary services are shared, bringing different product-customer combinations together is not sufficient to create a platform and enjoy its potential benefits.

One factor hindering platform approach implementation is heterogeneity of workforce training requirements, which increases the cost of sharing direct labour. In cases 1, 2 and 3, in which significantly different product types are processed within the same facility, cross-training of workers is too costly. Consequently, either VAS operators are not shared at all (case 1), or sharing only occurs when complex PDA operators are employed to carry out simpler PDAs (cases 2 and 3). Conversely, in case 7, workers are systematically shared among most productcustomer combinations. A few combinations, however, require such different training from the rest, owing to their product complexity or regulations, that they need a dedicated workforce. In case 6, finally, the workforce is shared among all product-customer combinations, but due to partially different processes and procedures, training requirements are not exactly the same for all combinations and, therefore, some cross-training is needed. Case 6 shows that even when customers with similar products are brought together, sharing of workforce may not be free.

A second hindrance factor in platform approach implementation is heterogeneity of equipment requirements, which increases the cost of sharing equipment and, at times, of indirect labour such as maintenance technicians. Cases 1, 2, 3 and 7 all exhibit some product-specific equipment, such as an antistatic floor for PoS terminals in case 3 or controlled-temperature storage containers for clinical trials in case 7, which would be too costly to use for the other products served within the same facility or campus. Furthermore, because of equipment specificity, clinical trials in case 7 require dedicated maintenance operators. Conversely, in case 6, in which the facility serves customers with similar products, the clean room where medication labelling and display building take place are shared without limitations.

Another factor that hinders resource-sharing among product-customer combinations is similarity of their target markets, meaning that the product-customer combinations are in direct When different product-customer combinations are in direct competition, it may be impossible not only to share workforce or equipment, but even to serve these combinations under the same roof, owing to confidentiality issues (cases 4 and 5). Furthermore, demand patterns for these combinations tend to overlap. When product-customer combinations face demand peaks and valleys simultaneously, opportunities for resource-sharing are slim, regardless of confidentiality issues, because capacity must be held at peak demand for each combination in order to ensure high responsiveness. Unsurprisingly, in cases 6 and 7, which exhibit high levels of resource-sharing, at least main customers are not direct competitors and demand patterns are, for the most part, complementary. This makes it possible for the 3PL to systematically share resources and, therefore, reduce the total capacity required without impairing the ability to match supply with demand and, hence, without delivery delays. Notably, there is less chance that direct competition and overlapping of demand patterns are a problem when different product types of the same customer are brought together, as witnessed by cases 2 and 3.

A fourth factor that negatively affects resource-sharing is heterogeneity of IT systems. Using different IT systems for different product-customer combinations not only prevents sharing of IT resources (case 1), but also may lead to duplication of IT staff. In case 6, for example, there are two people responsible for IT management, each trained in working with one of the two main systems in use at the facility. Different IT systems also make it more difficult to share processes and procedures, thereby hindering sharing of workforce (cases 6 and 7). The problem of heterogeneity of IT systems is more likely to arise when the same facility or campus serves different customers, as different customers may have different systems and may want the 3PL to use their system. Conversely, IT resources are more likely to be shared when different product types of the same customer are brought together, as shown by cases 2 and 3.

Another factor that influences the possibility of sharing resources among product-customer combinations brought together within the same facility or campus is the inclusion of distribution in the service supplied by the 3PL. In cases 2, 3 and 7, the 3PL provides all product-customer combinations a global service including distribution. Consequently, the company in charge of distribution is the same for all product-customer combinations and, whenever delivery points overlap, transport network is shared. On the contrary, in cases 1, 5 and 6, the 3PL does not provide distribution. Therefore, even when different product-customer combinations served within the same facility have overlapping delivery points, opportunities for sharing of trucks are lost because the carriers taking charge of finished goods transport are different.

A final challenge in platform approach implementation is to establish appropriate coordination mechanisms to re-allocate resources among product-customer combinations. Resource-sharing gives rise to reciprocal interdependence among different product-customer combinations. Therefore, mutual adjustment, defined as the transmission of new information during the process of action [START_REF] Thompson | Organizations in action[END_REF], is likely to be needed to manage such dependencies. In case 6, for example, there is one supervisor for each customer served at the facility, and each supervisor communicates with the operations manager whenever workloads for the corresponding customer are lower or higher than expected. The operations manager then adjusts the number of people assigned to each product-customer combination, diverting workers from the customers with temporary excessive capacity to the customers with insufficient capacity. In this case, sharing of workforce cannot rely on the establishment of a common schedule for the interdependent product-customer combinations, as different 3PL customers have different planning routines and transmit orders at different times during the day. Even when 13 resource-sharing involves different products of the same customer and the same IT system is used for all these products, differences in planning routines may hinder aggregate planning (cases 2 and 3) and, therefore, the need for lateral relations and mutual adjustment arises.

Integrating the above arguments concerning challenges facing a 3PL in implementation of the platform approach, we make the following observation.

Observation 3. The use of the platform approach to serve a given set of product-customer combinations is enabled by:

similarity of workforce training requirements among the product-customer combinations (3a), -similarity of equipment requirements among the product-customer combinations (3b), -similarity of IT systems among the product-customer combinations (3c), -dissimilarity of target markets among the product-customer combinations, meaning that the combinations are not in direct competition and have complementary demand patterns (3d), -provision of a distribution-included service to the product-customer combinations (3e), -reliance on coordination by mutual adjustment among the productcustomer combinations (3f).

Discussion and conclusions

The present study contributes to a better understanding of the potential benefits of 3PL-provided FP services by developing a framework that links FP service type, FP service value for the 3PL's customer, FP service organisational approach, and resource-sharing enablers (Figure 6). Insert Figure 6 This framework distinguishes different types of FP service, which have the potential to create value for the 3PL's customer through different mechanisms. On the one hand, existing-PDA FP services may enable the 3PL's customer to improve its operational and financial performance in serving geographical markets that the 3PL's customer was already supplying. In this case, the FP service does not necessarily lead to market advantages for the company buying the service. This is because, for instance, the 3PL's customer may decide not to translate its lower inventory-related costs to lower prices so as to increase sales. On the other hand, PDAenabling FP services are always aimed at producing market advantages, rather than cost savings, by making it possible for the 3PL's customer to enter and profitably serve new geographical markets.

Such a distinction extends previous research findings on the types of FP strategies and their performance implications for the company implementing FP. The extant FP literature focuses on FP strategies that concern existing PDAs and lead to improved operational performance [START_REF] Forza | Form postponement effects on operational performance: a typological theory[END_REF]. Market advantages, if any, are just a second-order outcome of the operational benefits produced by these FP strategies. Our results indicate a different type of FP strategy, which concerns new, rather than existing PDAs and which has the potential to improve company performance by producing direct market advantages, rather than by enhancing operational performance. Pragmatically, such a distinction has important implications for both 3PLs offering FP services and their potential customers. As regards 3PLs, they need to be ready to engage with not only logistics or supply chain directors, but also marketing directors if the main benefit of the offered FP service is to create market advantages rather than cost advantages. Likewise, potential customers should regard 3PL-provided FP services not only as a means of reducing costs, but also as a possible way to increase sales. Small and medium-sized companies, in particular, could find support for their strategies of market internationalisation and expansion. The 3PL's network could be crucial, in this case, in order to postpone the creation of the varieties targeted to the new markets to a point closer to the markets themselves. This means that smaller companies, who have been reported as using 3PL services to a lesser extent than large companies (e.g., [START_REF] Murphy | Third-party logistics usage: an assessment of propositions based on previous research[END_REF]Poist 1998, Hong et al. 2004), might look at 3PL service offerings with greater attention in the future.

Our findings also highlight the importance of the choice of the organisational solution with which an FP service will be provided. This is because through the choice of the FP service organisational approach, a 3PL has the possibility of increasing the value of an FP strategy, as compared to the situation in which the manufacturer implements FP in-house. By leveraging its serving of multiple customers, the 3PL can resort to organisational solutions, such as the multicustomer platform or the campus-style platform, which are not viable for individual manufacturers, and these solutions may mitigate a number of possible FP disadvantages. A major drawback of FP strategies, for example, is the increase in processing costs due to the loss of manufacturing scale economies and the need for excess capacity [START_REF] Yang | Postponement: an inter-organizational perspective[END_REF][START_REF] Harrison | Implications of form postponement to manufacturing: a cross case comparison[END_REF][START_REF] Forza | Form postponement effects on operational performance: a typological theory[END_REF]. By allowing use of the same capacity for a variety of customers, a multi-customer or campus-style platform decreases the total capacity required and, therefore, alleviates the negative effect of FP on processing costs. Other possible disadvantages of FP include higher transport costs, owing to direct deliveries to customers and the subsequent loss of logistics scale economies (Yang et al. 2005b[START_REF] Forza | Form postponement effects on operational performance: a typological theory[END_REF], and higher quality assurance costs when the postponed PDA is performed in the distribution channel [START_REF] Lee | Effective inventory and service management through product and process redesign[END_REF]Billington 1994, Forza et al. 2008). Again, the platform approach, if viable, can mitigate these FP drawbacks by reducing dependence on temporary labour without sacrificing volume flexibility and by enabling consolidation of finished goods shipments for a variety of customers.

The potential advantages of the platform approach appear particularly appealing as markets become more turbulent and 3PL customers are less willing to pay for committed capacity. Continuing downward pressure on prices is a major trend in the 3PL industry (e.g., [START_REF] Lieb | The North American third party logistics industry in 2004: the provider CEO perspective[END_REF], as also witnessed by most of our cases. As long as product-customer combinations face sufficiently high and stable demands, this challenge can be overcome while using the adhoc approach: for example, through automation or process improvement. When environmental turbulence increases, however, enhancing efficiency is more likely to require sharing of resources among multiple product-customer combinations in order to increase flexibility while decreasing the total capacity required. Nowadays, therefore, the platform approach no longer appears as a solution for serving only small customers who do not have scales that justify ad-hoc facilities. On the contrary, today the platform approach may also be crucial in increasing the value delivered to those large customers that have been traditionally served through ad-hoc facilities.

Our results, finally, indicate a number of challenges that face a 3PL in the supplying of an FP service through the platform approach. The possibility and cost of systematically sharing resources among a given set of product-customer combinations depend on the 3PL's ability to Variability of resource requirements may be a major obstacle to implementation of FP platforms, especially for large 3PLs serving many different product-customer combinations. Creating FP platforms may require coping with such a massive variability, for instance through appropriate location decisions. This means that besides traditional criteria for location problems, a 3PL should also consider resource-sharing enablers when deciding where a given productcustomer combination will be served. This also means that organisational barriers within a 3PL organisation may have to be overcome in order to create platforms. For example, a 3PL could create an FP platform by bringing together, within the same facility, product-customer combinations that belong to different industries, and as such are under the responsibility of different business units within the 3PL organisation, but have complementary demand patterns and similar resource requirements. Besides trying to cope with resource requirement variability, the 3PL should also strive to reduce such variability, seeking opportunities for increasing commonalities between the PDAs that are carried out, the machines that are used, the IT systems that are employed, etc. This could require, for instance, an increasing involvement of the 3PL in the design of the product families to which an FP service is to be provided.

The difficulty of reducing, or at least coping with, variability of resource requirements may eventually undermine the profitability of the concept of 3PL supplying FP services. The qualitative research approach adopted in this exploratory research, however, has not allowed us to investigate the conditions of economic viability of FP services from the 3PL perspective. Future research should address this issue, and this would require examining the relationships among the resource-sharing enablers identified in this study. There could be trade-offs, for instance, between increasing similarity of training and equipment requirements on the one hand, and reducing direct competition and overlapping of demand patterns on the other. Future studies could therefore be devoted to identifying which mixes of product-customer combinations, in terms of demand pattern characteristics, PDA characteristics, etc., are more advantageous to bring together in order to implement FP service platforms. In the pursuit of these research opportunities, we believe that our framework can assist by working as a conceptual model that guides the development of more detailed quantitative models (see [START_REF] Mitroff | On managing science in the systems age: two schemas for the study of science as a whole systems phenomenon[END_REF]) capable of assessing the economic viability of different types of FP services in many different specific contexts. Such quantitative models would help 3PLs to understand the profitability of FP services as compared to other commonly provided services, thus supporting definition of 3PL service offering.

By showing that a 3PL may be crucial in enabling another company to implement FP or has the possibility of increasing the value of FP as compared to the situation in which the other company implements FP in-house, this study adds to past research findings in the area of interorganisational FP. In our empirical inquiry, however, we have only got data from the 3PL, and this is another limitation of the present study. Future research would definitely benefit from collecting data from 3PL customers as well. This would allow, for example, in-depth investigation of the challenges and drawbacks of using FP services from a 3PL's customer perspective, which investigation was out of the scope of our research. The same printer may be localised by adding different components, such as power supply cables, manuals, stickers, etc., according to the country/market of destination. Further, customer-specific components, such as retailer-specific labels, may be added.

Program manager interviews (2) Facility visits (2) Archival documents 3 Electronics 2620 Hardware and software configuration of point-of-sale terminals A generic point-of-sale (PoS) terminal may be customconfigured (e.g., memory upgrade, Ethernet card to be included, software installation and firmware upgrade) just prior to dispatch of the finished product to the customer.

Program manager interviews (2)

Facility visits (2) Archival documents 4Personal care 2023 Co-packing of personal-care products

The same personal-care product may be packed together with different gifts according to the promotion conception.

Contract packing manager interviews (2) Facility visit Archival documents 5

Telecommunications 6120 Kitting of phone packs Different phone packs may be created by putting together, in a transparent box, different mobile phone handsets, subscriber identity module cards, marketing leaflets, promotional materials, etc. according to the promotion conception (average components per kit: 15). 2. FP services provided in the selected cases and value delivered to the 3PL's customer.

Business unit director interview

Case FP service

Value to the customer Explanation 2 Existing-PDA Improved operational and financial performance in serving existing geographical markets

The risks and associated costs of producing the wrong mix of printer variants are eliminated, as the customer no longer holds speculative stock of finished goods. Close-to-the-market specification of goods guarantees short delivery lead-times (1 day) and enhances responsiveness to varying demand in different countries, especially when launching or phasing out models. Fixed asset investment is reduced. Overhead decrease and volume flexibility increases because of one-stop-shop for all FP services provided to the customer.

1 Existing-PDA Improved operational and financial performance in serving existing geographical markets Speculative stock of high-value products is reduced while preserving on-hand availability of finished goods, as calculators are packed at a time closer to the moment of customer purchase and, hence, demand mix uncertainty is lower. Rework costs of leftover stock decrease, as the risk of overestimating a county's demand is lower. Lead-times in responding to unanticipated market requirements are shortened without using faster modes of transport. Investment in fixed assets is reduced. Overhead decrease due to resource-sharing among multiple product-customer combinations.

4

Existing-PDA

Improved operational and financial performance in serving existing geographical markets

The undifferentiated personal-care product is held in a location closer to the customer and is co-packed at a time closer to the promotional launch. As the promotion conception and sales forecast generation occur closer to the time when market demand is observed, there is less speculative stock and rework costs of leftover decrease. Lead-times in responding to unanticipated market conditions are shortened without use of faster modes of transport. Indirect operating costs decrease because of reduction in factory complexity. Investment in fixed asset is lower. Transport costs are reduced, as the undifferentiated product being shipped from the factory to the distribution centre is less bulky.

3 Existing-PDA

Improved operational and financial performance in serving existing geographical markets

PoS terminals are configured in a location closer to the market. Therefore, the customers can fully specify the product they need at a time closer to product delivery, when they have more information about the product features that will maximise their utility. Further, time and cost performance are not impaired by late order specification. Investment in fixed assets is reduced. Overhead decrease and capacity utilisation increases because of one-stop-shop for all FP services provided to the customer.

Distribution costs are lower due to overlapping of delivery points for different product families of the same customer.

PDAenabling Entry into a new geographical market

Serving the new market requires carrying out kitting activities to create different phone packs according to the promotion conception. However, the 3PL's customer would not carry out manufacturing activities in-house because of its focus on the development and commercialisation of mobile telecommunications services. Phone packs are built in a location close to the market and, hence, at a time close to the promotional launch. Consequently, inventory-holding costs are low and reaction time on market demand is fast. Investment in fixed assets is reduced.

PDAenabling Entry into a new geographical market

Serving the new market requires building different displays of OTC medicines for pharmacies according to the promotion conception. However, the 3PL's customer is a fabless company focused on the development and commercialisation of OTC products and would not carry out such activity in-house. As displays are built in a location close to the market, inventoryholding costs are low and lead-times in responding to unanticipated market conditions are short. Fixed asset investment is reduced. Overhead and operating costs are low due to resource-sharing among multiple product-customer combinations.

PDAenabling

Entry into new geographical markets

Serving the new markets in Europe requires adding different labels and literature to the medication according to the country of destination. The 3PL's customer, however, is a small US-based biotech company and could not profitably create these product variants at its laboratories, owing to the high risks and associated costs of keeping speculative inventory of finished goods. Likewise, the company could not set up a facility to create these variants in Europe because of its scale. Close-to-the-market labelling and packaging based upon market demand lead to little inventory waste, low rework costs and great responsiveness to specific country trends or regulatory change. Overhead, processing costs and distribution costs are low due to resourcesharing among multiple product-customer combinations. The 3PL handles certified translation of labels and provides a single point of contact for component approval in each country, thus simplifying the process for the customer. 3

Multi-product platform The facility currently serves two product families of the same customer: case 2 and case 3. In the future, the facility will serve a third product family of the same customer-business printerswhich require performance of localisation and technical configuration activities

Higher capacity utilisation and shared overhead Office and social areas, IT system, workforce, administrative staff, licences and other services are shared with all the other PCCs a served at the facility Reduced distribution costs The 3PL also provides distribution services and delivery points partially overlap among the PCCs a served at the facility. Therefore, small shipments dispatched directly to the customers are consolidated (Heterogeneity of training requirements) (configuration of PoS terminals-case 3-requires highly skilled workers, while kitting of consumer printers-case 2-does not. Due to the high costs of cross training, VAS operators for case 3 can be employed for case 2, but not vice versa.

More sharing of workforce is expected with the coming of business printers) (Heterogeneity of equipment requirements) (VAS equipment and areas not shared, as configuration of PoS terminals needs to be done in a semi-clean environment with safety regulations) Coordination by mutual adjustment Coordination by aggregate planning is hindered by the fact that the 3PL has 5 days of visibility over the customer's delivery schedule for PoS terminals, but only 1 day for consumer printers 6

Multi-customer platform

The facility provides logistics services to seven customers operating in the pharmaceutical industry and value-added services to three of them. However, a PDA is carried out for case 6 alone

Higher capacity utilisation and shared overhead Facility, equipment, workforce, part of the administrative staff, licences and other services are shared with all the other PCCs a at the facility Higher volume flexibility Workforce for a single customer can be increased up to 50% from one day to the next through sharing of permanent staff Reduced dependence on temporary labour All workers are permanent employees, except in July. This is the only period in which demand peaks for the PCCs a served at the facility overlap.

Demand patterns are for the most part complementary, as the customers serve different markets: hospitals and pharmacies (Heterogeneity of IT systems) (the IT system used for case 6 is customer's property and is common to only two PCCs a at the facility. Figure 5. Organisational approaches adopted in the selected cases to provide FP services.

Figure 6. The proposed framework linking FP service type, customer value, organisational approach and resource-sharing enablers. • PDA performed by the manufacturer at a factory on a to-forecast basis

• PDA performed by the 3PL in the distribution channel based on the order-driven master production schedule created by the manufacturer a For the sake of drawing simplicity and without any loss of generality, the figure assumes that before FP service provision, the 3PL was responsible for finished goods distribution activities.

Material decoupling point

Activities performed by the 3PL

a For the sake of drawing simplicity and without any loss of generality, the figure assumes that before FP service provision, the 3PL was responsible for finished goods distribution activities.

Material decoupling point Activities performed by the 3PL

To-Order

To-Order a For the sake of drawing simplicity and without any loss of generality, the figure assumes that before FP service provision, the 3PL was responsible for finished goods distribution activities Activities performed by the 3PL a For the sake of drawing simplicity and without any loss of generality, the figure assumes that before FP service provision, the 3PL was responsible for finished goods distribution activities.

  Dipartimento di Tecnica e Gestione dei sistemi industriali, Università di Padova, Stradella S.Nicola 3, 36100 Vicenza, Italy Zaragoza Logistics Center, Avenida Gómez Laguna 25, 50009 Zaragoza, Spain

  (2005) link higher levels of FP application to tighter contract restrictions on the magnitude and

  or have overlapping demand patterns.

  within the same facility or group of facilities, product-customer combinations with complementary demand patterns and with similar resource requirements.

  and experience to this research, as well as to the other members of the joint research project that involved this company, the Massachusetts Institute of Technology and the Zaragoza Logistics Center. In particular, the authors would like to thank C. Forza and F. Salvador for the suggestions and support given throughout this research project.

  labels and literature (27 country variants / 24 languages) are added to four strengths of one medication, which is to arrive at the 3PL's facility without label and blank carton.

  ) resource-sharing (dis)advantages Resource-sharing enablers (obstacles)

Figure 1 .

 1 Figure captionsFigure 1. Existing-PDA (from-forecast-to-order-driven-PDA) FP service.

Figure 2 .

 2 Figure 2. Existing-PDA (remaining-forecast-driven-PDA) FP service.

Figure 3 .

 3 Figure 3. Existing-PDA (remaining-order-driven-PDA) FP service.

Figure 4 .

 4 Figure 4. PDA-enabling FP service.

Figure 1 .

 1 Figure 1. Existing-PDA (from-forecast-to-order-driven-PDA) FP service.

Figure 2 .a

 2 Figure 2. Existing-PDA (remaining-forecast-driven-PDA) FP service.

Figure 3 .a

 3 Figure 3. Existing-PDA (remaining-order-driven-PDA) FP service.

FigureFigure 5 .Figure 6 .

 56 Figure 4. PDA-enabling FP service.

Table 1 .

 1 Description of the selected cases and data sources.

	Case	Industry	ISIC	PDA(s) performed by the 3PL	PDA(s) description	Main data sources
			code	in the distribution channel
	1	Electronics	2817	Kitting of calculators	The same calculator may be packed together with different or	Contract operations manager
					optional components, such as manuals, cables, marketing	interviews (2)
					leaflets etc., according to the country/market of destination	Facility visits (2)
					(from 6 to 20 components per kit). Different possible types of packaging, such as cardboard boxes, pizza-style boxes or	Archival documents
					clamshells, may be used.
	2	Electronics	2620	Kitting of consumer printers

  Three different, either customer-owned or 3PL-owned, IT systems are used at the facility, with subsequent duplication of IT staff) (Heterogeneity of training requirements) (though products are similar, cross-training of workforce is needed because of different processes and procedures among the PCCs a served at the facility. IT staff is cross-trained as well, owing to the use of different IT systems)

				(Distribution not included in the service)
				(distribution provided by two small transport companies operating in the local
				market)
				Coordination by mutual adjustment
				Need for mutual adjustments between the supervisors in charge of each
				customer's operations, as the customers have different planning routines and
				place delivery orders on a daily basis but at different points in time
	7	Campus-style platform	Higher capacity utilisation and shared overhead	(Heterogeneity of training and equipment requirements and IT systems)
		35 customers in the	Inbound/storage/outbound areas, VAS areas, office	(Clinical trial customers have a few dedicated resources-storage/outbound areas,
		pharmaceuticals, medical	and social areas, material handling and VAS	equipment, workforce, part of the administrative staff, licences, customer
		devices and hospitals	equipment, workforce, IT system, administrative	service-due to specific regulations and laws that are different from normal
		industries are served in three	staff, licences and other services are shared among	pharmaceuticals. Likewise, another PCC a has a few dedicated resources-
		facilities close to each other.	different PCCs a served within the campus	inbound/storage/outbound areas, VAS area and equipment, workforce-because
		The customers are provided both logistics and value-added services. PDAs are carried out for case 7 and another PCC a requiring assembly of different surgical kits	Reduced dependence on temporary labour All workers are permanent employees Reduced distribution costs The 3PL also provides distribution services and consolidates small shipments, thanks to partial overlapping of delivery points among the PCCs a	customer-specific IT system, processes and procedures, and training are needed in order to work with a very large amount of stock-keeping units-7500 possible end items) Coordination by mutual adjustment Mutual adjustments between resource planners of different customer are needed, as the customers have different planning routines

a Product-customer combination.

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  For the sake of drawing simplicity and without any loss of generality, the figure assumes that before FP service provision, the 3PL was responsible for finished goods distribution activities.

			International Journal of Production Research
				Manufacturing and distribution cumulative lead time Manufacturing and distribution cumulative lead time
	SUPPLY CHAIN CONFIGURATION BEFORE FP SERVICE a SUPPLY CHAIN CONFIGURATION BEFORE FP SERVICE a	To-Forecast To-Forecast	DP DP DP	To-Order To-Order
	• PDA performed by the manufacturer	PDA PDA
	at a factory
	on a to-forecast basis			time time
	created by the manufacturer in the distribution channel based on the order-driven master production schedule o r • PDA performed by the 3PL F SUPPLY CHAIN CONFIGURATION AFTER FP SERVICE SUPPLY CHAIN CONFIGURATION AFTER FP SERVICE	To-Forecast To-Forecast	PDA PDA DP DP DP	To-Order To-Order	time time
	Key: Key: Key:	PDA PDA PDA DP DP DP DP	P Product Differentiation Activity (PDA) Product Differentiation Activity (PDA) Product Differentiation Activity (PDA) e r e Material decoupling point Material decoupling point Material decoupling point	Non-PDA Non-PDA Non-PDA Activities performed by the 3PL Activities performed by the 3PL Activities performed by the 3PL	Activity lead time Activity lead time Activity lead time
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://mc.manuscriptcentral.com/tprs Email: ijpr@lboro.ac.uk a

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			International Journal of Production Research
				Manufacturing and distribution cumulative lead time Manufacturing and distribution cumulative lead time
	SUPPLY CHAIN CONFIGURATION BEFORE FP SERVICE a SUPPLY CHAIN CONFIGURATION BEFORE FP SERVICE a	To-Forecast To-Forecast		DP DP DP	To-Order To-Order
	• PDA performed by the manufacturer • PDA performed by the manufacturer	PDA PDA
	at a factory at a factory
	on a to-forecast basis on a to-forecast basis				time time
	SUPPLY CHAIN CONFIGURATION AFTER FP SERVICE • PDA performed by the 3PL SUPPLY CHAIN CONFIGURATION AFTER FP SERVICE • PDA performed by the 3PL F in the distribution channel in the distribution channel o based on the forecast-driven master production schedule based on the forecast-driven master production schedule r created by the manufacturer created by the manufacturer	To-Forecast To-Forecast	PDA PDA	DP DP DP	To-Order To-Order	time time
							Activity lead time Activity lead time Activity lead time
	Key: Key: Key:	PDA PDA PDA DP DP DP DP	P Product Differentiation Activity (PDA) Product Differentiation Activity (PDA) Product Differentiation Activity (PDA) e r e Material decoupling point Material decoupling point	Non-PDA Non-PDA Non-PDA Activities performed by the 3PL Activities performed by the 3PL
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http://mc.manuscriptcentral.com/tprs Email: ijpr@lboro.ac.ukInternational Journal of Production Research

Acknowledgements

This paper benefited from the many insightful comments made by two anonymous reviewers. The author is also grateful to the numerous managers of a third-party logistics provider who

 3. Organisational approaches adopted in the selected cases to provide FP services, effects on customer value, and implementation challenges.

Case

Organisational approach (Lack of) resource-sharing (dis)advantages Resource-sharing enablers (obstacles) 5

Ad-hoc

The facility is dedicated to case 4 (Capacity underutilisation) (8 assembly lines, but only 2 of them are used out of peak periods) (Dependence on temporary labour) (up to 100 temporary workers in peak periods.

Lower productivity due to learning curves. Temporary labour sometimes difficult to find) (Customers serving the same market) (the customer would not allow resource-sharing with direct competitors, owing to confidential information related to promotions) (Distribution not included in the service) (distribution provided by another 3PL operating in the local market) 4

Ad-hoc The facility is dedicated to case 5

(Capacity underutilisation) (7 assembly lines, but only 3 of them are used out of peak periods) (Dependence on temporary labour) (up to 250 temporary workers in peak periods) (Customers serving the same market) (the customer would not allow resource-sharing with direct competitors, owing to confidential information related to promotions)

1

Ad-hoc

The facility is divided in six compartments for six customers operating mainly in the semiconductor industry. They are provided both logistics and valueadded services, but PDAs are performed for case 1 alone Shared overhead Part of the office and social areas, part of the administrative staff, licences and other services are shared with all the other PCCs a at the facility (Capacity underutilisation) (unused capacity in quarters 1 and 4) (Dependence on temporary labour) (kitting subcontracted to a sheltered workshop guaranteeing up to 100 operators in peak periods. Need for multiple quality checks in kitting lines) (Loss of potential savings in distribution costs) (lost opportunities for shipment consolidation despite partial overlapping of delivery points) (Heterogeneity of IT systems) (the IT system used for case 1 is customer's property and is different from those used for the other PCCs a served at the facility) (Heterogeneity of training and equipment requirements) (no VAS operators are shared with the other PCCs a served at the facility, owing to different training requirements and high costs of cross-training. Sealing machines are specific to kitting activities and cannot be shared with the other PCCs a served at the facility) (Distribution not included in the service) (the customer performs all distribution management on its own and decides which transport to take from which 3PL)

2 Multi-product platform The facility currently serves two product families of the same customer: case 2 and case 3. In the future, the facility will serve a third product family of the same customer-business printerswhich require performance of localisation and technical configuration activities

Shared overhead

Office and social areas, IT system, administrative staff, licences and other services are shared with all the other PCCs a served at the facility Higher volume flexibility and reduced dependence on temporary labour Easier up-and down-scaling of personnel resources through sharing of permanent staff Reduced distribution costs Small direct-to-customer shipments are consolidated thanks to 3PL-provided distribution and partial overlapping of PCCs' delivery points (Heterogeneity of training requirements) (configuration of PoS terminals-case 3-requires highly skilled workers, while kitting of consumer printers-case 2-does not. Due to the high costs of cross training, VAS operators for case 3 can be employed for case 2, but not vice versa.

More sharing of workforce is expected with the coming of business printers) (Heterogeneity of equipment requirements) (VAS equipment and areas not shared, as configuration of PoS terminals needs to be done in a semi-clean environment with safety regulations) Coordination by mutual adjustment Coordination by aggregate planning is hindered by the fact that the 3PL has 5 days of visibility over the customer's delivery schedule for PoS terminals, but only 1 day for consumer printers (continued)


Volker Kaechele

Markus Moehler

Manfred P Lutz

Goetz Wichert

Miriam Eisele

Jochen Klaus

Peter R Galle

Guido Adler

Thomas Seufferlein
email: thomas.seufferlein@medizin.uni-halle.de

• Goetz Von Wichert

Thomas Seuverlein

G Von Wichert

A phase I/II study of oxaliplatin and paclitaxel in patients with non-resectable cancer of the oesophagus and adenocarcinoma of the gastro-oesophageal junction: a study of the Arbeitsgemeinschaft Internistische Onkologie

Keywords: Oxaliplatin, Paclitaxel, Cancer of the gastro-oesophageal junction, Oesophageal cancer, Chemotherapy

ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Introduction

Carcinoma of the upper gastrointestinal tract represents a major health problem worldwide [START_REF] Kamangar | Patterns of cancer incidence, mortality and prevalence across Wve continents: deWning priorities to reduce cancer disparities in diVerent geographical regions of the world[END_REF][START_REF] Cameron | Symptomatic gastro-oesophageal reXux as a risk factor for oesophageal adenocarcinoma[END_REF]. About 90% of all patients diagnosed with oesophageal cancer will die as a consequence of this disease. Besides the predominantly late diagnosis, another reason for this poor prognosis of this tumour is the limited eVectiveness of systemic therapy.

Even if there is no established standard chemotherapy regimen, cisplatin-containing combination therapies are accepted as a standard of care. Oxaliplatin is a third-generation platinum compound with a favourable toxicity proWle as compared to cisplatin [START_REF] Cunningham | Capecitabine and oxaliplatin for advanced esophagogastric cancer[END_REF][START_REF] Al-Batran | Phase III trial in metastatic gastroesophageal adenocarcinoma with Xuorouracil, leucovorin plus either oxaliplatin or cisplatin: a study of the AIO[END_REF].

Taxanes, microtubule-stabilising agents initially isolated from the PaciWc yew, have been extensively studied in gastro-oesophageal cancer. Paclitaxel and Docetaxel demonstrated encouraging activity in single and combination therapy [START_REF] Ilson | Paclitaxel given by a weekly 1-h infusion in advanced oesophageal cancer[END_REF][START_REF] El-Rayes | A phase II study of carboplatin and paclitaxel in oesophageal cancer[END_REF][START_REF] Lorenzen | Split-dose docetaxel, cisplatin and leucovorin/Xuorouracil as Wrst-line therapy in advanced gastric cancer and adenocarcinoma of the gastroesophageal junction: results of a phase II trial[END_REF][START_REF] Van Cutsem | Phase III study of docetaxel and cisplatin plus Xuorouracil compared with cisplatin and Xuorouracil as Wrst-line therapy for advanced gastric cancer: a report of the V325 Study Group[END_REF].

123

Oxaliplatin is a potent inhibitor of Survivin, which enhances paclitaxel-induced apoptosis and mitotic catastrophe in colon and gastric cancer cell lines. These Wndings made the combination of these two drugs an attractive option for clinical trials [START_REF] Fujie | Oxaliplatin, a potent inhibitor of survivin, enhances paclitaxel-induced apoptosis and mitotic catastrophe in colon cancer cells[END_REF][START_REF] Gu | Low-dose oxaliplatin enhances the antitumor eYcacy of paclitaxel in human gastric cancer cell lines[END_REF].

This phase I/II study was conducted to assess the eYcacy and tolerability of paclitaxel and oxaliplatin in patients with non-resectable cancer of the oesophagus and/ or adenocarcinoma of the gastro-oesophageal junction. The treatment regimen was adapted from a phase II study by Petrasch in which paclitaxel 90 mg/m 2 was followed by cisplatin 50 mg/m 2 resulting in an overall remission rate of 40% (8/20) including 15% (3/20) clinically complete responses with a favourable toxicity proWle [START_REF] Petrasch | Chemotherapy with cisplatin and paclitaxel in patients with locally advanced, recurrent or metastatic oesophageal cancer[END_REF]. By substituting oxaliplatin for cisplatin we aimed at obtaining an even better tolerability.

Methods

Patients

Patients with non-resectable cancer of the oesophagus and adenocarcinoma of the gastro-oesophageal junction were eligible for this study. A measurable lesion according to the RECIST criteria was required [START_REF] Therasse | New guidelines to evaluate the response to treatment in solid tumours: European Organization for Research and Treatment of Cancer, National Cancer Institute of the United States, National Cancer Institute of Canada[END_REF]. Prior surgery and/or radiochemotherapy was allowed as well as one prior chemotherapy in a neoadjuvant or adjuvant setting that did not contain oxaliplatin and/or taxanes. This chemotherapy had to be terminated at least 6 months prior to enrolment into the study. This paper focusses on the subgroup of 26 chemotherapy-naive patients (84% of the whole study population). The remaining Wve patients had previously received systemic chemotherapy. An ECOG performance status of •2 was mandatory as well as adequate bone marrow, kidney and liver function.

Chemotherapy schedules and treatment evaluation

Oxaliplatin 85 mg/m 2 was administered over 2 h followed by paclitaxel 90 mg/m 2 over 3 h both on day 1. Treatment was administered fortnightly.

All patients were assessed for toxicity during the study period according to the National Cancer Institute Common Toxicity Criteria (NCI-CTC). Oxaliplatin-related peripheral neuropathy was described on a scale from 1 to 4 adapted from the classiWcation of Wasserman et al. [START_REF] Wassermann | Combination of oxaliplatin plus irinotecan in patients with gastrointestinal tumours: results of two independent phase I studies with pharmacokinetics[END_REF].

According to the study protocol an evaluation of tumour response was mandatory every 6 weeks. For locally advanced cancer a further evaluation regarding secondary resectability was obligatory after 12 weeks. Response and overall survival were assessed using an intent-to-treat analysis.

Statistical considerations

The response rate was the primary end point of this phase I/II trial. Chemotherapy-naive and pre-treated patients were analysed separately. A Chi-square test was utilised.

For chemotherapy-naive patients a sample size of 38 patients, who were assessable for response evaluation, was calculated to reject an initial hypothesis (H0) of a response rate •30% with an alpha error of 0.1.

For the calculation of the sample size the programme, nQuery Advisor Release 3.0 (Statistical Solutions Ltd., Cork, Ireland, 1999), was used.

An interim analysis after inclusion of 25 chemo-naive patients revealed that the response rates were too low to reject the H0 hypothesis. Subsequently, recruitment was stopped prematurely.

Results

Between November 2002 and May 2005 31 patients were enrolled into the study at the two participating centres (University hospitals of Ulm and Mainz in Germany). A total of 64 cycles was administered to 26 chemotherapynaive patients. The patient demographic data and characteristics are summarised in Table 1. Patients with CNS metastasis, uncontrolled heart disease and/or clinical evidence of pre-existing peripheral neuropathy were excluded.

Toxicity

Of the 26 chemo-naive patients, 23 (88%) were evaluable for toxicity; 3 patients could not be evaluated owing to early withdrawal of consent or early dropout for reasons other than toxicity prior to, or during, the Wrst cycle of treatment. The majority of toxic eVects were grade 1/2, whereas grade 3/4 toxicity was rare. Events leading to hospitalisation occurred in Wve patients; one patient had two hospitalisations. Three patients required endoscopic intervention because of an increase in dysphagia (n = 3). Other causes were ileus owing to peritoneal carcinosis (n = 1), hypercalcemia (n = 1) and pneumonia (n = 1).

Haematological toxicity

Haematological toxicity was rare. Overall 13% of patients (n = 3) experienced grade 3/4 neutropenia. Febrile neutropenia was not observed. One patient had grade 3 thrombopenia.

123

Non-haematological toxicity

No grade 4 non-haematological toxicity was encountered; 87% (n = 20) encountered neurosensory toxicity ¸grade 1, but only 13% (n = 3) had grade 3 neurosensory toxicity leading to a dose reduction of oxaliplatin. One patient had a hypersensitivity grade 2 shortly after infusion of paclitaxel during the third treatment cycle. There was only grade 1/2 gastrointestinal toxicity that included diarrhoea grade 1 in 17%, nausea in 22%, emesis in 9% and mucositis in 9% of the patients. These Wndings are summarised in Table 2.

Treatment eYcacy

Response

The overall conWrmed response rate for all treatment-naive patients (n = 26) by the intention-to-treat analysis was 15% with four patients having a conWrmed partial response. Together with 15 patients who achieved stable disease during the initial restaging the disease control rate was 73%. This included two patients enrolled who did not undergo radiological response evaluation, because they exited the study early for reasons other than tumour progression: one patient exited the study during the Wrst treatment cycle owing to early withdrawal of consent; one patient was excluded owing to surgery of symptomatic bone metastasis that was already prevalent at the time of entering the trial.

Time to progression

Twenty-four patients were included for the calculation of TTP. Two patients who changed to another treatment regimen (deWnitive radio-chemotherapy) without progress during the investigational treatment were excluded from 3) with a 1-year progression-free survival rate of 13%.

Overall survival

The median OS for chemotherapy-naive patients was 12.3 months (range 1.5-66) with 1-year survival rate of 50%. Table 2 provides an overview. Information on the second-line treatment was available for 24 patients (92%); 10 patients (42%) did not receive further systemic treatment after discontinuation of the study, whilst 4 patients had radio-chemotherapy and 10 patients had chemotherapy alone.

Discussion

This study was conducted to assess the eYcacy and tolerability of paclitaxel and oxaliplatin in patients with nonresectable cancer of the oesophagus and/or adenocarcinoma of the gastro-oesophageal junction. The primary goal of the study to reject the initial hypothesis (H0) of a response rate •30% was not met.

Oxaliplatin was given at a dose of 85 mg/m 2 fortnightly which is commonly used within the FOLFOX4-regimen in colorectal cancer or the FLO-regimen in gastric cancer [START_REF] Al-Batran | Phase III trial in metastatic gastroesophageal adenocarcinoma with Xuorouracil, leucovorin plus either oxaliplatin or cisplatin: a study of the AIO[END_REF][START_REF] André | Multicenter phase II study of bimonthly high-dose leucovorin, Xuorouracil infusion, and oxaliplatin for metastatic colorectal cancer resistant to the same leucovorin and Xuorouracil regimen[END_REF]. The oxaliplatin dose administered compared well to other oxaliplatin/taxane-containing doublets for the treatment of oesophago-gastric cancer. A phase II trial by Richards used 130 mg/m 2 oxaliplatin together with Docetaxel 60 mg/m 2 on day 1 of a 3-week treatment cycle in patients with advanced gastric cancer and/or adenocarcinoma of the gastro-oesophageal junction [START_REF] Richards | Phase II trial of docetaxel and oxaliplatin in patients with advanced gastric cancer and/or adenocarcinoma of the gastroesophageal junction[END_REF]; 36% had a partial response and 40% of the patients in this trial had at least stable disease 6 months after entry into the study. Median PFS and OS were 4.3 and 8.5 months, respectively; 70% had grade 3/4 neutropenia.

In oesophageal cancer the use of paclitaxel was investigated in diVerent platinum-containing doublets: in a phase I study in metastatic oesophageal cancer paclitaxel was administered weekly as a 1-h infusion at a dose of 100 mg/ m 2 followed by a 1-h infusion of carboplatin targeting an AUC of 2-5 mg £ min/ml. Of 37 patients evaluable for response, 1 complete response and 19 partial responses accounted for an overall response rate of 54% [START_REF] Polee | A phase I and pharmacokinetic study of weekly paclitaxel and carboplatin in patients with metastatic esophageal cancer[END_REF]. In a phase II study for patients with resectable squamous cell carcinoma of the oesophagus, paclitaxel 180 mg/m 2 and cisplatin 60 mg/m 2 were given fortnightly with a similar response rate of 59%; a grade 3/4 neutropenia occurred in 71% of patients. With a median OS of 9 months for all patients this excellent response rate did not lead to an improved OS [START_REF] Polee | Phase II study of neo-adjuvant chemotherapy with paclitaxel and cisplatin given every 2 weeks for patients with a resectable squamous cell carcinoma of the esophagus[END_REF]. One reason for the inferior response rate in our trial was that we examined a lower dose of paclitaxel (90 mg/m 2 every 2 weeks as compared to 175 mg/m 2 every 3 weeks or 135 mg/m 2 every 2 weeks), although we used an equivalent dose of oxaliplatin.

The drug combination of paclitaxel and oxaliplatin was used in Wrst-line treatment of patients with advanced NSCLC and ovarian cancer (paclitaxel 175 mg/m 2 and oxaliplatin 130 mg/m 2 given every 21 days), in both tumours with impressive response rates [START_REF] Winegarden | A phase II study of oxaliplatin and paclitaxel in patients with advanced non-small-cell lung cancer[END_REF][START_REF] Viens | A phase II study of a paclitaxel and oxaliplatin combination in platinumsensitive recurrent advanced ovarian cancer patients[END_REF]. In advanced gastric cancer, a phase II trial added leucovorin 400 mg/m 2 and 5-FU 2,400 mg/ m 2 to paclitaxel 135 mg/m 2 and oxaliplatin 85 mg/m 2 given fortnightly; 12 out of 21 patients with measurable lesions had a treatment response. In 30% of the patients, neutropenia grade 3/4 occurred [START_REF] Lin | A phase II study of 5-Xuorouracil/leucovorin in combination with paclitaxel and oxaliplatin as Wrst-line treatment for patients with advanced gastric cancer[END_REF].

Our study protocol diVers from other recently published trials that yielded response rates higher than 40% [START_REF] Cunningham | Capecitabine and oxaliplatin for advanced esophagogastric cancer[END_REF][START_REF] Al-Batran | Phase III trial in metastatic gastroesophageal adenocarcinoma with Xuorouracil, leucovorin plus either oxaliplatin or cisplatin: a study of the AIO[END_REF][START_REF] Lorenzen | Split-dose docetaxel, cisplatin and leucovorin/Xuorouracil as Wrst-line therapy in advanced gastric cancer and adenocarcinoma of the gastroesophageal junction: results of a phase II trial[END_REF][START_REF] Van Cutsem | Phase III study of docetaxel and cisplatin plus Xuorouracil compared with cisplatin and Xuorouracil as Wrst-line therapy for advanced gastric cancer: a report of the V325 Study Group[END_REF] owing to the lack of a Xuoropyrimidine compound, which might be a reason for the lower response rate observed here. We used a sequence of oxaliplatin followed by paclitaxel as compared to the reverse sequence applied in the other trials [START_REF] Winegarden | A phase II study of oxaliplatin and paclitaxel in patients with advanced non-small-cell lung cancer[END_REF][START_REF] Viens | A phase II study of a paclitaxel and oxaliplatin combination in platinumsensitive recurrent advanced ovarian cancer patients[END_REF]. Pre-clinical data published shortly after the end of our recruitment period revealed that in human cancer cell lines the sequence of paclitaxel followed by oxaliplatin showed synergistic eVects on apoptosis, whereas the opposite sequence potentially yielded antagonistic eVects [START_REF] Tanaka | In vitro schedule-dependent interaction between paclitaxel and oxaliplatin in human cancer cell lines[END_REF]. In contrast, a recently published phase I study provided a favourable pharmacokinetic proWle for the sequence used in our study regimen [START_REF] Bekaii-Saab | A phase I and pharmacokinetic study of weekly oxaliplatin followed by paclitaxel[END_REF].

Conclusions

Taken together, in a palliative setting when response rate is not paramount, our treatment protocol achieved a satisfactory disease control rate. The mTTP of 4.5 months observed in this trial and the mOS of 12.3 months are also comparable to other but often more toxic regimens. However, a second-line treatment which was administered in 58% of patients might have inXuenced this parameter. However, the response rate observed does not qualify our treatment regimen for a neoadjuvant setting. Thus, our results suggest that this regimen with oxaliplatin and paclitaxel is a very well tolerable palliative treatment option for patients with non-resectable advanced cancer of the oesophagus and the gastro-oesophageal junction.

ConXict of interest statement

The authors declare that they have no competing interests.

  19 (73%) (conWrmed PR + SD 58%, n = 15) PD 7 (27%) Median TTP (n = 24) 4.5 months Median OS 12.3 months 123 the TTP analysis. The median TTP was 4.5 months (range 0.8-19.

Table 1

 1 Characteristics of chemo-naive patients (n = 26)

	Characteristic	Number of patients	%
	Sex
	Male	23	88
	Female	3	12
	Age (years)
	Median	59.5
	Range	46-81
	ECOG performance status
	0	7	2 7
	1	1 6	6 1
	2	3	1 2
	Tumour stage (UICC)
	III	3	12
	IV	23	88
	Tumour localisation
	Oesophagus	21	81
	Mid-part	12	46
	Lower part	9	35
	Gastro-oesophageal junction	5	19
	Tumour histology
	Squamous cell carcinoma	19	73
	Adenocarcinoma	7	27
	Table 2 Toxicity and eYcacy of the treatment	Toxicity NCI grade 2/3/4 (n = 23)	Grade 2 (%)	Grade 3 (%)	Grade 4 (%)


Error estimates based on equilibrated residuals for domain decomposition methods

Ivana Pultarova

Error estimates based on equilibrated residuals for domain decomposition methods

List of authors:

I. Pultarová 1
During numerical solution of partial differential equations by some iterative method preconditioned by domain decomposition, a good error indicator could help us to decide whether the error of a current approximation to the solution is sufficiently low or not on a particular subdomain. If we use domain decomposition methods balanced by constraints [START_REF] Mandel | Multispace and Multilevel BDDC[END_REF], we can then decrease or increase the number of coarse degrees of freedom on these subdomains. We derive our error estimates from the equilibrated residual strategy which is described in [START_REF] Ainsworth | A Posteriori Error Estimation in Finite Element Analysis[END_REF] and further developed e.g. in [START_REF] Vejchodský | Guaranteed and locally computable a posteriori error estimate[END_REF]. In our contribution we discuss how this can be applied to domain decomposition methods without much additional effort.

In classical applications, fluxes over all element edges of a finite element solution are calculated and smoothed in some sense on every patch of elements which share a single vertex. Then the energy norm of the error is computed from solutions of Neumann problems on elements. In our approach we exploit this basic idea, but there are two main differences. First, instead of patches of elements we use subdomains and moreover, only interface unknowns are calculated with. Second, we can compute the estimates in every iteration, it means that we do not need the exact solution of an underlying linear system.

Instead of a posteriori error estimates, this method rather yields suggestions of residual partitioning for iterative methods preconditioned by a domain decomposition method.

Department of Mathematics, Facuty of Civil Engineering, Czech Technical University in Prague 1