Albiglutide has been developed for the treatment of type 2 diabetes mellitus (T2DM) as an adjunct to diet and exercise, as monotherapy, or in combination with existing therapies and has been approved by the United States (US) Food and Drug Administration (FDA), the European Medicines Agency (EMA) and other regulatory agencies. This is a 26 week, open-label, single group, multicenter, extension study to Study 200952. This extension study will provide extended safety, tolerability and immunogenicity data for the albiglutide liquid drug product. This extension study will comprise 2 study periods: treatment (26 weeks) and post-treatment follow-up (8 weeks). A maximum of 300 subjects will be eligible to take part in this extension study.