TECHNICAL FIELD OF THE INVENTION

Aspects and embodiments of the present invention relate to the treatment of neurological disorders such as for example, Alzheimer's disease and Parkinson's disease. Particularly, certain embodiments relate to GIP/GLP-1 co-agonist peptides for use in the treatment of these two neurological disorders. Also included in the present invention are inter alia pharmaceutical compositions comprising the GIP/GLP-1 co-agonist peptides, together with methods of treating such disorders as well as other subject matter.

BACKGROUND TO THE INVENTION

Alzheimer's disease (AD) is a chronic neurodegenerative disorder for which there is at present no cure. Currently prescribed medication only temporarily relieves some of the symptoms. The main hallmarks of the disease are disorientation, loss of memory, loss of neurons and synapses in the brain, the accumulation of beta-amyloid protein in the brain (amyloid plaques), and intracellular aggregation of hyperphosphorylated tau protein (tangles) (LaFerla and Oddo, 2005; Blennow et al., 2006).

Parkinson's disease (PD) is also a chronic neurodegenerative disease for which currently only delaying medication is available. The main hallmarks are tremor, rigor, and a loss of ability to move, the degeneration of neurons in the basal brain (substantia nigra) and the loss of release of the neurotransmitter, dopamine (Shen, 2010).

Type 2 diabetes (T2DM) has been identified as a risk factor for AD and PD (Holscher, 2014), indicating that insulin signalling impairment may be a factor in initiating or accelerating the development of AD. Epidemiological studies found a clear correlation between T2DM and the risk of developing AD or other neurodegenerative disorders at a later stage (Luchsinger et al., 2004; Ristow, 2004; Ohara et al., 2011). It was also shown that insulin signalling in the brain is desensitized in AD patients. Recent studies demonstrated that brains of AD patients had increased levels of inactivated phosphorylated insulin receptors and IRS-1 second messengers, which are both indicative of insulin desensitization (Moloney et al., 2010; Bomfim et al., 2012; Talbot et al., 2012). In PD, insulin signalling was also found to be impaired and linked to disease progression (Morris et al., 2011; Cereda et al., 2012). Glucagon-like peptide (GLP-1) is an endogenous 30-amino acid peptide incretin hormone (Baggio and Drucker, 2007). GLP-1 receptor stimulation enhances beta-cell proliferation in the pancreas by activating stem cell proliferation, facilitates glucose-dependent insulin secretion and lowers blood glucose in patients with T2DM (Lovshin and Drucker, 2009). Three GLP-1 analogues are currently on the market as a treatment for diabetes, exendin-4 (Byetta®, Bydureon®), lixisenatide (Lyxumia®) and liraglutide (Victoza®) (Campbell and Drucker, 2013; Elkinson and Keating, 2013).

Glucose-dependent insulinotropic peptide (GIP), also known as gastric inhibitory polypeptide, is a 42-amino acid incretin hormone which activates pancreatic islets to enhance insulin secretion and to help reduce postprandial hyperglycaemia, similar to GLP-1 (Gault et al., 2003). GIP is a member of the secretin/glucagon family of neuroregulatory polypeptides which also include the growth hormone releasing factor. It is expressed in pancreatic alpha cells, endocrine cells, and also in neurons in the brain (Nyberg et al., 2007; Campbell and Drucker, 2013). GIP has also been shown to promote pancreatic beta-cell growth, differentiation, proliferation and cell survival, documenting its growth-hormone properties (Gault et al., 2003). Therefore, research is on-going to develop GIP as a therapeutic tool for T2DM treatment (Irwin et al., 2006). There are currently no GIP analogues authorised for the treatment of T2DM.

Dual agonist peptides which target more than one receptor are being considered for the treatment of T2DM. Several GIP/GLP-1 co-agonist peptides are currently in development for the treatment of T2D. However, there are currently no GIP/GLP-1 dual receptor agonists authorised for use to treat T2DM.

Recent investigations of the neuroproperties of GLP-1 and GIP have indicated that these peptides may play a role in preventing neurodegenerative hallmarks in several mouse models of Alzheimer's disease (AD) and also in animal models of Parkinson's disease (PD).

Insulin as well as the incretins not only have growth-factor like properties in the brain, but also modulate synaptic activity (Holscher, 2014). Synapses are the contacts between neurons, and they are important for memory formation and information processing in the brain. Direct injection of GLP-1 or long-lasting GLP-1 analogues into the brain markedly enhanced long-term potentiation of synaptic transmission (LTP) in the hippocampus, a brain area that is involved in memory formation. LTP is considered a cellular correlate of memory formation (Bliss and Collingridge, 1993). The GLP-1 analogue, liraglutide, has been shown to upregulate LTP in the rat brain (McClean et al., 2010).

In addition, GLP-1 analogues were able to prevent the impairment of LTP that was induced by beta-amyloid fragments (Gault and Holscher, 2008a; McClean et al., 2011; Gengler et al., 2012; Han et al., 2013). This impairment of LTP by amyloid protein may be the mechanism by which amyloid causes memory loss (Cleary et al., 2005). A study testing liraglutide in an APP/PS1 mouse model of AD showed that the drug can prevent the impairment in memory formation and synaptic plasticity, the reduction of total numbers of synapses, normalise stem cell proliferation and neurogenesis in the dentate gyrus, reduce the inflammation response, and furthermore reduce amyloid plaque load in the cortex and total amyloid levels in the brain (McClean et al., 2011). In another study, liraglutide also had protective and regenerative effects in very old transgenic mice, demonstrating that even at an advanced stage of disease progression, memory can be improved and plaque load be reduced to some degree (McClean and Holscher, 2014).

Based on these findings in animal models, a pilot clinical trial in Alzheimer's patients has been conducted. The finding was that the GLP-1 analogue liraglutide protected the disease-induced degeneration of brain activity and energy utilization. This demonstrates that the drug enters the brain and protects neurons from the damaging effects of Alzheimer's while keeping neurons active and functional (Gejl et al., 2016). A phase II clinical trial of liraglutide in AD patients has started (NCT01843075).

Furthermore, one prior art study has investigated the effects of the GLP-1 receptor agonist exendin-4 in the 6-hydroxydopamine model of PD. After the lesion was induced, rats were treated with exendin-4 and a protection of motor activity was observed. Histological analysis showed that exendin-4 significantly increased the number of both tyrosine hydroxylase- and vesicular monoamine transporter 2-positive neurons in the substantia nigra (Bertilsson et al., 2008). In a second study, two rodent models of PD, 6-hydroxydopamine (6-OHDA) and lipopolysaccharide (LPS), were used to test the effects of exendin-4. Motor control was much improved in the drug group, and striatal tissue concentrations of dopamine were markedly higher. In addition, exendin-4 reversed the loss of extracellular DA in the striatum (Harkavyi et al., 2008). When testing the GLP-1 receptor agonists liraglutide and lixisenatide in the MPTP mouse model of Parkinson's disease, it was found that both drugs showed good effects in preventing the motor impairment, chronic inflammation in the brain, and loss of dopaminergic neurons induced by the toxin MPTP (Liu et al., 2015).

Based on these studies, a clinical trial of exendin-4 in PD patients had been initiated. This study reported that in several motor assessments and in a cognitive test, patients had improved, and the improvements were maintained even after the drug had been discontinued for 12 months (Aviles-Olmos et al., 2013; Aviles-Olmos et al., 2014). A phase II clinical trial in Parkinson's patients testing the drug liraglutide has started (NCT02953665).

Studies have also been carried out to determine whether GIP or GIP analogues have an effect in AD. It has been found that GIP analogues can prevent the LTP impairment that beta-amyloid fragments induce on synaptic transmission in the brain (Gault and Holscher, 2008b). In a GIP receptor-deletion mouse strain, LTP was also impaired, and paired-pulse facilitation was reduced, indicating that the release of synaptic vesicles is reduced (Faivre et al., 2011). The long-lasting GIP analogue D-Ala2-GIP also had neuroprotective effects in an APP/PS1 mouse model of AD. In 12 months old mice, synaptic plasticity in area CA1 of the hippocampus and spatial memory formation was impaired in APP/PS1 mice but was unimpaired in D-Ala2-GIP treated APP/PS1 mice. In addition, the amyloid plaque load was much reduced, showing impressive effects in reducing the main hallmarks of AD (Faivre and Holscher, 2013b).

In aged 19 month old AD mice, the drug was still able to reverse some of the AD symptoms such as synapse loss (Faivre and Holscher, 2013a). In a longitudinal study, oxidative stress and the inflammation response in the brain was much reduced in APP/PS1 mice (Duffy and Holscher, 2013). This suggests that these analogues have neuroprotective properties in AD and protect synapses from the detrimental effects of beta-amyloid.

In the MPTP mouse model of Parkinson's disease, the GIP analogue D-Ala2-GIP was protective and prevented the impairment of motor activity, the loss of dopaminergic neurons, loss of synapses and the chronic inflammation response induced by MPTP (Li et al., 2015). When testing a novel dual GLP-1/GIP dual agonist in this mouse model, it was found that it showed good protective effects (Ji et al., 2015). However, that particular molecule was not as effective as GLP-1 analogues.

There remains a need to identify treatments for neurological disorders such as for example the neurodegenerative diseases, Alzheimer's disease and Parkinson's disease.

It is an aim of certain embodiments of the present invention to at least partly mitigate the problems associated with the prior art.

It is an aim of certain embodiments of the present invention to provide a therapeutic peptide for use in the treatment and/or prevention of a neurodegenerative disorder such as for example Alzheimer's disease and/or Parkinson's disease.

It is an aim of certain embodiments of the present invention to provide novel GIP/GLP-1 dual agonist peptides which have superior efficacy as compared to the best in class GLP-1 mono agonist liraglutide, for use in the treatment and/or prevention of Alzheimer's or Parkinson's disease.

It is an aim of certain embodiments of the present invention to provide GIP/GLP-1 dual agonist peptides which have superior properties as compared to a GIP mono agonist. Examples of superior properties include for example a greater decrease in beta-amyloid plaque load and/or reduction of motor skill impairment.

It is an aim of certain embodiments of the present invention to provide novel GIP/GLP-1 dual agonist peptides for use in the treatment and/or prevention of a neurodegenerative disorder such as for example Alzheimer's disease and/or Parkinson's disease.

SUMMARY OF THE INVENTION

In one aspect of the present invention, there is provided a GIP/GLP-1 co-agonist peptide or a pharmaceutically acceptable salt or solvate thereof for use in the treatment and/or prophylaxis of a neurological disorder, wherein the co-agonist peptide is represented by the general formula 1:

(I)(SEQ. ID. No. 1)Tyr-Aib-Glu-Gly-Thr-Phe-Thr-Ser-Asp-Tyr-Ser-Ile-Tyr-Leu-Asp-Lys-Gln-Ala-Ala-Aib-Glu-Phe-Val-Xaa24-Trp-Leu-Leu-Ala-Gly-Y1-Y2-R2wherein Xaa24is selected from Asn and Cys;Y1 is selected from absent or an extension comprising at least eight amino acid molecules;Y2 is selected from:

(SEQ. ID. No 2)Lys-Lys-Lys-Lys-Lys;(SEQ. ID. No. 3)Lys-Lys-Lys-Lys-Lys-Lys(SEQ. ID. No 4)Arg-Arg-Gln-Arg-Arg-Lys-Lys-Arg-Gly-Tyr;and(SEQ. ID. No 5)Lys-Arg-Arg-Gln-Arg-Arg-Lys-Lys-Arg-Gly-Tyr;R2is selected from —NH2 or —OH, or a derivative or a pharmaceutically acceptable salt or solvate of the peptide or the derivative.

In certain embodiments, Y2 is Lys-Lys-Lys-Lys-Lys or Lys-Lys-Lys-Lys-Lys-Lys.

In certain embodiments, Y2 is Arg-Arg-Gln-Arg-Arg-Lys-Lys-Arg-Gly-Tyr or Lys-Arg-Arg-Gln-Arg-Arg-Lys-Lys-Arg-Gly-Tyr.

In certain embodiments, Xaa24is Cys. In certain embodiments, Xaa24is Asn.

In certain embodiments, Y1 is an extension comprising at least 10 amino acids e.g. at least 11 amino acids.

In certain embodiments, Y1 is selected from:

(SEQ. ID. No. 6)Gly-Pro-Ser-Ser-Gly-Ala-Pro-Pro-Pro-Ser;(SEQ. ID. No. 7)Gly-Pro-Ser-Ser-Gly-Ala-Pro-Pro-Pro-Ser-Lys;(SEQ. ID. No. 8)Gly-Pro-Ser-Ser-Gly-Ala-Pro-Pro-Pro-Ser-Cys;(SEQ. ID. No. 9)Pro-Ser-Ser-Gly-Ala-Pro-Pro-Pro-Ser;(SEQ. ID. No. 10)Pro-Ser-Ser-Gly-Ala-Pro-Pro-Ser;
and absent.

Aptly, Y1 is Gly-Pro-Ser-Ser-Gly-Ala-Pro-Pro-Pro-Ser (SEQ. ID. No. 6). In certain embodiments, Y1 is Gly-Pro-Ser-Ser-Gly-Ala-Pro-Pro-Pro-Ser-Cys (SEQ. ID. No 8). In an alternative embodiment, Y1 is Gly-Pro-Ser-Ser-Gly-Ala-Pro-Pro-Pro-Ser-Lys (SEQ. ID. No. 7).

In certain embodiments, the peptide comprises a hydrophilic moiety covalently linked to an amino acid. In certain embodiments, the peptide comprises a hydrophilic moiety covalently linked to an amino acid at position 24.

In certain embodiments, the peptide comprises a hydrophilic moiety covalently linked to an amino acid at position 39 or 40, when Y1 is an extension comprising at least 10 amino acids or at least 11 amino acids.

In certain embodiments, Xaa39or Xaa40is Cys and the peptide comprises a hydrophilic moiety covalently linked to Cys(39) or Cys(40).

In certain embodiments, Xaa24is Cys and the peptide comprises a hydrophilic moiety covalently linked to Cys(24).

In certain embodiments, the hydrophilic moiety is a water-soluble polymer.

In certain embodiments, the water-soluble polymer is a polyethylene glycol moiety and optionally is a polyethylene glycol moiety having a molecular weight of between about 20,000 Daltons and about 60,000 Daltons. In certain embodiments, the peptide is conjugated with a lipophilic substituent.

In certain embodiments, the lipophilic substituent comprises a hydrocarbon chain having 8 to 24 carbon (C) atoms. In certain embodiments, the lipophilic substituent comprises an acyl group.

In certain embodiments, the lipophilic substituent is a fatty acid molecule. Aptly, the fatty acid molecule is selected from a C-8 octanoyl group, a C-10 decanoyl group, a C-12 lauroyl group, a C-14 myristoyl group, a C-16 palmitoyl group, a C-18 stearoyl group and a C-20 acyl group.

In certain embodiments, the lipophilic substituent is attached to an amino acid at the carboxyl-terminus of the peptide. In certain embodiments, the lipophilic substituent is attached to an amino acid at position 40. Aptly, the lipophilic substituent is covalently bonded to a side chain of an amino acid of the peptide.

In certain embodiments, the peptide comprises a spacer which conjugates the lipophilic substituent to an amino acid residue. Aptly, the spacer is a residue from a naturally occurring or unnatural amino acid, wherein the spacer comprises a residue of Gly, Pro, Ala, Val, Leu, Ile, Met, Cys, Phe, Tyr, Trp, His, Lys, Arg, Gin, Asn, α-Glu, γ-Glu, ε-Lys, Asp, Ser, Thr, Gaba, Aib, β-aminohexonyl, 7-aminoheptanoyl, 8-aminooctanoyl, 9-aminononanoyl, 10-aminodecanoyl or 8-amino-3,6-dioxaoctanoyl.

In certain embodiments, the spacer is γ-Glu. In certain embodiments, the spacer is a dipeptide, optionally wherein the spacer comprises two negatively charged amino acids and further optionally wherein the spacer is γ-Glu-γ-Glu.

In certain embodiments, the peptide further comprises one or more conservative substitutions.

In certain embodiments, the peptide comprises the amino acid sequence of:

(SEQ. ID. No. 11)YXEGTFTSDYSIYLDKQAAXEFVNWLLAGGPSSGAPPPSKKKKKK-NH2
wherein X=aminoisobutyric acid.

In certain embodiments, the peptide consists essentially of the amino acid sequence of:

(SEQ. ID. No. 11)YXEGTFTSDYSIYLDKQAAXEFVNWLLAGGPSSGAPPPSKKKKKK-NH2
wherein X=aminoisobutyric acid.

In certain embodiments, the peptide comprises the amino acid sequence of:

(SEQ. ID. No. 12)YXEGTFTSDYSIYLDKQAAXEFVNWLLAGGPSSGAPPPSKRRQRRKKRGY-NH2
wherein X=aminoisobutyric acid.

Aptly, the peptide consists essentially of the amino acid sequence of:

(SEQ. ID. No. 12)YXEGTFTSDYSIYLDKQAAXEFVNWLLAGGPSSGAPPPSKRRQRRKKRGY-NH2
wherein X=aminoisobutyric acid.

In a further aspect of the present invention, there is provided a peptide as described herein for use in the treatment and/or prophylaxis of a neurological disorder.

In a further aspect of the present invention, there is provided a peptide as described herein for use in the treatment of a neurological disorder which is caused by or associated with beta-amyloid protein plaque deposition in an area of the patient. In certain embodiments, the beta-amyloid plaque deposition is in the brain of the patient.

In a further aspect of the present invention, there is provided a peptide as described herein for use in the treatment and/or prophylaxis of a neurological disorder caused by, or associated with, dysfunction of long-term potentiation of synaptic transmission.

In a further aspect of the present invention, there is provided a peptide as described herein is for use in the treatment and/or prophylaxis of a neurological disorder caused by, or associated with, inflammation.

In a further aspect of the present invention, there is provided a peptide as described herein for use in the treatment of a neurological disorder associated with motor impairment.

In a further aspect of the present invention, there is provided a peptide as described herein for use in the treatment and/or prophylaxis of a neurological disorder affecting cognitive function, e.g. dementia, stroke, schizophrenia and/or bipolar disorder.

In certain embodiments, the disorder is cerebral ischemia associated with stroke.

In certain embodiments, the peptide is for use in the treatment and/or prophylaxis of a disorder selected from post-traumatic stress disorder, epilepsy, Tourette's syndrome, and hallucinations; and dysfunctional cognitive processes, optionally selected from attention, calculation, memory, judgment, insight, learning and reasoning.

In certain embodiments, the peptide is for use in the treatment and/or prophylaxis of a neurodegenerative disorder e.g. Alzheimer's disease, Parkinson's disease, Amyotrophic Lateral Sclerosis, peripheral neuropathy, Huntington's disease and Creutzfeldt-Jacob disease.

Aptly, the neurological disorder is multiple sclerosis.

In certain embodiments, the peptide is for use in the treatment and/or prophylaxis of a neurological disorder selected from clinical or pre-clinical Alzheimer's disease, prodromal Alzheimer's disease, and clinical or preclinical amyloid angiopathy (CAA).

Aptly, the peptide is for use in the treatment and/or prophylaxis of clinical Alzheimer's disease.

In a further aspect of the present invention, there is provided a peptide as described herein for use in the treatment and/or prophylaxis of Parkinson's disease.

Also provided is a method of treating and/or preventing a neurological disorder as described herein, the method comprising administering a pharmaceutically effective amount of a GIP/GLP-1 co-agonist peptide as described herein to a subject in need thereof.

In a further aspect of the present invention, there is provided a method of treating and/or preventing a neurological disorder comprising administering to a patient in need thereof a pharmaceutical composition comprising a GIP/GLP-1 co-agonist peptide, or a derivative or a pharmaceutically acceptable salt or solvate of the peptide or the derivative,wherein said co-agonist peptide is represented by the general Formula I:

(I)(SEQ. ID. No. 1)Tyr-Aib-Glu-Gly-Thr-Phe-Thr-Ser-Asp-Tyr-Ser-Ile-Tyr-Leu-Asp-Lys-Gln-Ala-Ala-Aib-Glu-Phe-Val-Xaa24-Trp-Leu-Leu-Ala-Gly-Y1-Y2-R2wherein Xaa24is selected from Asn and Cys;Y1 is selected from absent or an extension comprising at least eight amino acid molecules;Y2 is selected from:

(SEQ. ID. No 2)Lys-Lys-Lys-Lys-Lys;(SEQ. ID. No. 3)Lys-Lys-Lys-Lys-Lys-Lys(SEQ. ID. No 4)Arg-Arg-Gln-Arg-Arg-Lys-Lys-Arg-Gly-Tyr;and(SEQ. ID. No 5)Lys-Arg-Arg-Gln-Arg-Arg-Lys-Lys-Arg-Gly-Tyr;R2is selected from —NH2 or —OH, or a derivative or a pharmaceutically acceptable salt or solvate of the peptide or the derivative.

Aptly, the peptide is as described herein.

In certain embodiments, the neurological disorder is selected from post-traumatic stress disorder, epilepsy, Tourette's syndrome, and hallucinations; and dysfunctional cognitive processes, optionally selected from attention, calculation, memory, judgment, insight, learning and reasoning.

In certain embodiments, the neurological disorder is a neurodegenerative disorder. Aptly, the neurodegenerative disorder is selected from Alzheimer's Disease, Parkinson's Disease, Huntington's disease, Amyotrophic Lateral Sclerosis, peripheral neuropathy, and Creutzfeldt-Jacob disease.

In certain embodiments, the neurological disorder is a neurological disorder selected from clinical or pre-clinical Alzheimer's disease, prodromal Alzheimer's disease, and clinical or preclinical amyloid angiopathy (CAA). APTLY, the neurological disorder is clinical Alzheimer's Disease.

In a further aspect of the present invention, there is provided a peptide for use in the treatment and/or prophylaxis of clinical Alzheimer's Disease, the peptide consisting of the following sequence:

(SEQ. ID. No. 11)YXEGTFTSDYSIYLDKQAAXEFVNWLLAGGPSSGAPPPSKKKKKK-NH2
wherein X=aminoisobutyric acid.

In a further aspect of the present invention, there is provided a peptide for use in the treatment and/or prophylaxis of clinical Alzheimer's Disease, the peptide consisting of the following sequence:

(SEQ. ID. No. 12)YXEGTFTSDYSIYLDKQAAXEFVNWLLAGGPSSGAPPPSKRRQRRKKRGY-NH2
wherein X=aminoisobutyric acid.

In one embodiment, the peptide comprises or consists of the following amino acid sequence:

(SEQ. ID. No. 11)YXEGTFTSDYSIYLDKQAAXEFVNWLLAGGPSSGAPPPSKKKKKK-NH2
X=aminoisobutyric acid

This peptide is referred to herein as “DA4” and has an amino acid sequence as set forth in SEQ. ID. No. 11.

In one embodiment, the peptide comprises or consists of the following amino acid sequence:

(SEQ. ID. No. 12)YXEGTFTSDYSIYLDKQAAXEFVNWLLAGGPSSGAPPPSKRRQRRKKRGY-NH2
X=aminoisobutyric acid

This peptide is referred to herein as “DA5” and has an amino acid sequence as set forth in SEQ. ID. No. 12.

The ability to cross the blood-brain barrier may have utility in the treatment of neurodegenerative disorders. Without being bound by theory, it is considered that the peptides of certain embodiments of the present invention are able to cross the blood-brain barrier. Furthermore, the peptides of certain embodiments cross the blood-brain barrier at an enhanced rate as compared to known GIP/GLP-1 co-agonist peptides.

It is noted that there can be many difficulties in transmission of a peptide across the blood brain barrier. A number of different mechanisms for enhancing access across the blood-brain barrier have been considered, one of which is the modification of peptide sequences. However, whilst a number of peptide modifications are known to potentially assist in crossing the blood-brain barrier, their in vivo behaviour is difficult to predict. Their addition to a peptide or protein molecule may be ineffective or lead to inactivation of the peptide or protein e.g. by protein degradation processes, incorrect peptide folding patterns and/or a change in receptor binding properties of the peptide.

Aptly, the peptide is for use in the treatment and/or prevention of Alzheimer's disease or Parkinson's disease.

Also provided herein is a pharmaceutical composition which comprises GIP/GLP-1 receptor co-agonist peptides as described herein and a pharmaceutically acceptable carrier for use in the treatment and/or prophylaxis of a neurological disorder as described herein. Further provided in the present disclosure is a kit including such a pharmaceutical composition.

