Drug repurposing for rare: progress and opportunities for the rare disease community.

Repurposing is one of the key opportunities to address the unmet rare diseases therapeutic need. Based on cases of drug repurposing in small population conditions, and previous work in drug repurposing, we analyzed the most important lessons learned, such as the sharing of clinical observations, reaching out to regulatory scientific advice at an early stage, and public-private collaboration. In addition, current upcoming trends in the field of drug repurposing in rare diseases were analyzed, including the role these trends could play in the rare diseases' ecosystem. Specifically, we cover the opportunities of innovation platforms, the use of real-world data, the use of artificial intelligence, regulatory initiatives in repurposing, and patient engagement throughout the repurposing project. The outcomes from these emerging activities will help progress the field of drug repurposing for the benefit of patients, public health and medicines development.

Half-life prolongation of therapeutic proteins by conjugation to ATIII-binding pentasaccharides: a first-in-human study of CarboCarrier® insulin.

AIM: Conjugation to antithrombin III ATIII-binding pentasaccharides has been proposed as a novel method to extend the half-life of therapeutic proteins. We aim to validate this technological concept in man by performing a first-in-human study using CarboCarrier® insulin (SCH 900948) as an example. A rising single dose phase 1 study was performed assessing safety, tolerability, pharmacokinetics and relative bioactivity of CarboCarrier® insulin. Safety, tolerability and pharmacokinetics (PK) of single doses of CarboCarrier® insulin in healthy volunteers were explored, and the dose-response relationship and relative bioactivity of CarboCarrier® insulin in subjects with type 2 diabetes were investigated. METHODS: After an overnight fast, subjects were randomized to a treatment sequence. PK and pharmacodynamic (glucose, insulin and C-peptide) samples were obtained for up to 72 h post-dose. Effects of CarboCarrier® insulin were compared with those of NPH-insulin. RESULTS: CarboCarrier® insulin was safe and well-tolerated and no consistent pattern of adverse events occurred. CarboCarrier® insulin exposure (Cmax and AUC) increased proportionally with dose. The mean terminal elimination half-life ranged between 3.11 and 5.28 h. All CarboCarrier® insulin dose groups showed decreases in the mean change from baseline of plasma glucose concentrations compared with the placebo group. CONCLUSIONS: CarboCarrier® insulin is pharmacologically active showing features of insulin action in man. The elimination half-life of the molecule was clearly extended compared with endogenous insulin, indicating that conjugation to ATIII-binding pentasaccharides is a viable approach to extend the half-life of therapeutic proteins in humans. This is an important step towards validation of the CarboCarrier® technology by making use of CarboCarrier® insulin as an example.

Synthetic heparin derivatives as new anticoagulant drugs.

The journey towards a detailed mechanistic understanding of the anticoagulant action of heparin has resulted in synthetic mimetics with improved pharmacodynamic profiles. Inspired by the ternary complex formation of heparin with antithrombin III and thrombin, the active pentasaccharide fondaparinux has been succeeded by several clinical candidates, such as SR123781, that have tailor-made factor Xa and thrombin inhibitory activities combined with less aspecific binding (e.g. binding to platelet factor 4 involved in thrombocytopenia). Novel compounds with both antithrombin III-mediated inhibition of factor Xa and direct thrombin inhibition are emerging. Org42675 is one such compound, balancing dual inhibition of factor Xa and thrombin in one anticoagulant drug, with excellent pharmacokinetic properties and strong inhibitory activity toward clot-bound thrombin.

Synthesis and Evaluation of a Series of Long-Acting Glucagon-Like Peptide-1 (GLP-1) Pentasaccharide Conjugates for the Treatment of Type†2 Diabetes.

The present study details the development of a family of novel D-Ala(8) glucagon-like peptide-1 (GLP-1) peptide conjugates by site specific conjugation to an antithrombin III (ATIII) binding carrier pentasaccharide through tetraethylene glycol linkers. All conjugates were found to possess potent insulin-releasing activity. Peptides with short linkers (<25 atoms) conjugated at Lys(34) and Lys(37) displayed strong GLP-1 receptor (GLP-1-R) binding affinity. All D-Ala(8) GLP-1 conjugates exhibited prominent glucose-lowering action. Biological activity of the Lys(37) short-linker peptide was evident up to 72 h post-injection. In agreement, the pharmacokinetic profile of this conjugate (t1/2 , 11 h) was superior to that of the GLP-1-R agonist, exenatide. Once-daily injection of the Lys(37) short-linker peptide in ob/ob mice for 21 days significantly decreased food intake and improved HbA1c and glucose tolerance. Islet size was decreased, with no discernible change in islet number. The beneficial effects of the Lys(37) short-linker peptide were similar to or better than either exenatide or liraglutide, another GLP-1-R agonist. In conclusion, GLP-1 peptides conjugated to an ATIII binding carrier pentasaccharide have a substantially prolonged bioactive profile compatible for possible once-weekly treatment of type 2 diabetes in humans.

From heparin to EP217609: the long way to a new pentasaccharide-based neutralisable anticoagulant with an unprecedented pharmacological profile.

The elucidation of the structure of the antithrombin binding sequence in heparin has given a large impulse to the rational design of heparin related drugs. De novo chemical synthesis of the corresponding pentasaccharide as well as simplified analogues has provided very specific, antithrombin-mediated inhibitors of factor Xa with various pharmacokinetic profiles. Fondaparinux and idraparinux are examples of such compounds that have found clinical application as antithrombotics. Because of the very specific binding to antithrombin the pharmacokinetics of pentasaccharides can be predicted and transferred to other molecules covalently bound to them. The new chemical entities thus obtained display a wide array of antithrombotic activities, giving improved heparin molecules as well as new anticoagulants, devoid of the undesired side effects of heparin and with unprecedented pharmacological profiles. In this context, a direct thrombin inhibitor was covalently coupled to a pentasaccharide by an inert spacer. This compound, EP42675 exerts antithrombin mediated anti-factor Xa activity together with direct thrombin inhibiting capacity. It displays favourable pharmacokinetics as imposed by the pentasaccharide. EP42675 was further modified by the introduction of a biotin moiety in its structure. The new entity obtained, EP217609 exerts the same pharmacological profile as EP42675 and it can be instantaneously neutralised by injection of avidin. Due to this unprecedented mechanism of anticoagulant activity and its ability to be neutralised, EP217609 deserves to be investigated in clinical settings where direct thrombin inhibition is required.

A versatile approach towards regioselective platinated DNA sequences.

Undesired N(7) platination of 2'-deoxyguanosine residues at predetermined sites in an oligodeoxynucleotide (ODN) sequence is prevented by applying the sterically demanding diphenylcarbamoyl (DPC) as an O(6)-protecting group. The presence of a base-labile oxalyl linker between the immobilized 3'-nucleotide and controlled pore glass (CPG) allows cleavage of the protected ODN from the support and leaves DPC protection unaffected. This method provides an ODN with specifically blocked guanine-N(7) sites for platination. In the hexanucleotides prepared in this study, 5'-GGBGGT-3'(for B=T, C and A), a platinum GG adduct is introduced at G4,G5. These site-specific platinated hexamers were isolated in a yield of 65 %, and were fully characterized by using reversed-phase HPLC (high performance liquid chromotography), LCMS (liquid chromatography-mass spectrometry), MALDI-TOF MS (matrix-assisted laser desorption/ionization time-of-flight mass spectrometry), PAGE (polyacrylamide gel electrophoresis) and Maxam-Gilbert sequencing analysis.