PhaseBio Raises $23M to Continue Clinical Development of Polymer-Fused Diabetes Drugs

PhaseBio Pharmaceuticals raised $23 million in a third tranche of its Series B round of financing, taking the total raised to $48.4 million. The funds will be used to support Phase IIb clinical development of the firm’s GLP-1 analogue Glymera against type 2 diabetes, as well as complete a Phase I/IIa clinical trial evaluating the long-acting basal insulin Insumera, and carry out a Phase I clinical study with the firm’s first-in-class VPAC2 selective agonist, Vasomera, in patients with stage 1 and 2 essential hypertension. Additional preclinical work will also be undertaken to support clinical development of Vasomera for treating acute and chronic heart failure and pulmonary hypertension.

PhaseBio is exploiting its elastin-like polymer (ELP) technology to develop new and improved drugs against endocrine, metabolic, and cardiovascular disease, which can be more easily administered and demonstrate improved stability, bioavailability, and activity. ELPs are derived from a five amino acid motif found in elastin. The technology has been primarily exploited to generate ELP-fused proteins and peptides that retain therapeutic activity, but demonstrate much better solubility, greater stability, and longer half-life due to the ELP domain. Modifying the sequence of the individual ELP subunits and polymer length provides the means to further optimize the physical and chemical properties of each ELP-fusion protein.

The ELP technology has also been adapted as a carrier for small molecule drugs. In this case multiple copies of hydrophobic drug molecules are attached to the ELP, which triggers self-assembly of the resulting ELP-drug conjugate into well-defined nanoparticles. PhaseBio claims that in comparison with naked drug molecules, ELP-based drug nanoparticle formulations demonstrate much higher solubility, improved bioavailability, circulation time, and efficacy.

PhaseBio’s lead product, Glymera, is recombinant GLP-1 ELP fusion drug in development as a potentially once-weekly treatment for type 2 diabetes that the firm claims doesn’t cause the nausea associated with other GLP-1 analogs. Insumera is a fully mature insulin molecule (B and A chains) genetically fused to the ELP polymer. Vasomera is the firm’s ELP-fused Vasoactive Intestinal Peptide (VIP) analogue, which is in development initially for the treatment of hypertension.

The genetic fusion proteins are generated in PhaseBio’s E. coli expression system. However, the firm claims yeast and mammalian systems can also be used in cases where post-translational modifications to the protein are required.