Subcutaneous administration achieved endpoints in Phase 1 trial and support evaluation of an intravenous trial

Malvern, PA, June 18, 2013 — PhaseBio Pharmaceuticals, a clinical-stage biopharmaceutical company focused on diabetes and cardiovascular diseases, today announced the successful completion of a Phase 1 trial of Vasomera™ (PB1046), the first once-weekly investigational, VPAC2 selective receptor agonist for the treatment of cardiopulmonary diseases. This multi-center, randomized, double-blind, placebo-controlled trial demonstrated the safety, tolerability and pharmacokinetic (PK)/pharmacodynamic (PD) response of single ascending subcutaneous (SC) doses of Vasomera in 40 patients. Trial results showed PD activity that was supportive of a once-weekly dosing regimen that could allow for chronic use in a home setting.

“Vasomera offers a unique combination of activities that not only treats the symptoms, but potentially alters the underlying pathophysiology of cardiopulmonary diseases,” said Chris Prior, Ph.D., chief executive officer, PhaseBio. “We are pleased with the progress of this program. The completion of this trial not only represents an important milestone for Vasomera, but also provides validation of our elastin-like polypeptide technology platform with three distinct clinical product candidates in development.”

In this Phase 1 trial, Vasomera was generally well tolerated with no clinically relevant cardiovascular safety signals identified. The Company plans to submit the full data set to an upcoming major medical meeting.

Initiation of Phase 1 Trial with Vasomera Intravenous (IV) Administration

Based on the clinical results of the Phase 1 trial evaluating SC Vasomera, PhaseBio has initiated a second Phase 1 trial to evaluate the safety, tolerability and PK/PD response of single ascending doses of short-term IV-infused Vasomera. IV administration of Vasomera would enable use in an acute hospital setting, with the goal of preserving or improving hemodynamic function in heart failure and reducing the incidence of re-hospitalization.

The trial is expected to enroll up to 32 patients and will evaluate the acute impact of Vasomera on hemodynamic function using echocardiographic analyses. It will also provide support for the development of Vasomera for treatment of acute heart failure as well as pulmonary arterial hypertension (PAH). The trial is expected to complete in the third quarter of 2013.

About Vasomera

VIP is a neuropeptide with diverse cardiovascular effects.  Its actions are mediated through stimulation of the G protein-coupled receptors VPAC1 and VPAC2. VIP has been shown to be deficient in patients with various types of cardiopulmonary diseases. Historically, clinical development of VIP as a pharmaceutical product has been hampered by the rapid inactivation and clearance of the native peptide from circulation. Native VIP has been shown to have a half-life of less than two minutes. Using PhaseBio’s proprietary elastin-like polypeptide (ELP) technology fused to VIP, the Company created Vasomera, an in vivo-stable, VPAC2 selective receptor, long-acting form of VIP. The Company has demonstrated, through multiple nonclinical studies, the positive effects of Vasomera in models with induced heart failure and pulmonary arterial hypertension.  Additionally, literature supports the demonstration of positive effects of VIP in models with cystic fibrosis.

About PhaseBio

PhaseBio is a clinical-stage biopharmaceutical company developing novel drugs to treat diabetes, metabolic and cardiovascular diseases. The Company’s proprietary platform technology uses elastin-like polypeptides (ELPs) to control the half-life, bioavailability and physical characteristics of the molecule for ease of administration. The resulting drug products are tuned for a specific rate of absorption, thereby, potentially increasing efficacy and reducing side effects. The Company’s lead development candidates are PB1023, a once-weekly GLP-1 analogue for type 2 diabetes; PE0139, a novel ultra long acting basal insulin ELP fusion; and Vasomera, a weekly vasoactive intestinal peptide (VIP) agonist for acute and chronic heart failure and pulmonary arterial hypertension. PhaseBio is privately owned with headquarters and research laboratories in Malvern, Pennsylvania.