Phase 2b Trial of Pemziviptadil, Peptide Treatment for PAH, Enrolling in US

Marisa Wexler, MS avatar

by Marisa Wexler, MS |

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Enrollment is resuming for the VIP clinical trial, which is evaluating PhaseBio Pharmaceuticals‘ investigational therapy pemziviptadil (PB1046) in people with pulmonary arterial hypertension (PAH).

The trial, which is recruiting adult patients at sites across the U.S., underwent a brief pause in enrollment owing to effects of the COVID-19 pandemic.

“[We are] pleased to be resuming enrollment for VIP, our Phase 2b trial of pemziviptadil for patients with pulmonary arterial hypertension,” Jonathan P. Mow, CEO of PhaseBio, said in a press release.

Pemziviptadil is an analogue of vasoactive intestinal peptide (VIP). This peptide (small protein) is a hormone that acts to lower blood pressure, as well as reduce inflammation and fibrosis (scarring).

The VIP peptide that is normally produced in the human body degrades quickly — when injected, it is eliminated within minutes, according to PhaseBio. Pemziviptadil is a form of the peptide modified to last longer in the body, making it better suited for use as a medication. The therapy is designed to be administered by subcutaneous (under-the-skin) injection once a week.

This Phase 2b VIP trial (NCT03556020) — short for Vasoactive Intestinal Peptide in adult patients with pulmonary arterial hypertension — is evaluating pemziviptadil in up to 63 adults, ages 18 to 79, with PAH.  Information on its U.S. study locations and their contacts can be found here.

Participants will be randomized to one of two dose regimes of pemziviptadil: some will be given the minimally effective low dose (0.2 mg/kg) throughout the trial, while others will start at this dose and then receive higher doses up to a maximally tolerated dose. This maximal dose, as the name implies, is the highest that can be given without concerns for intolerable side effects.

The trial’s main goals are to evaluate the therapy’s safety, assessed by the occurrence of adverse events, as well as its effects on vital signs (e.g., blood pressure, body temperature, and heart rate) and laboratory measures. Other measures, including mean pulmonary artery pressure and assessments of physical function, will also be evaluated.

Patients who complete the trial will have the opportunity to enroll in its open-label extension study, called VIP EXTEND (NCT03795428) that runs through January 2024.

About 90% of previously enrolled patients who completed the 16-week main trial have elected to continue treatment in the extension study, PhaseBio reported in an October release.

VIP trial results are expected in the second half of 2021.

A previous Phase 1b/2a pilot study (NCT03315507) that enrolled three PAH patients showed positive safety, with no serious adverse events reported. A case report detailing data on one of these three people, presented by PhaseBio at a science conference earlier this year, showed improvements over time in measures of treatment efficacy.

Improvements reported with this patient, treated for about 18 months, included a decrease in mean blood pressure of the pulmonary artery, and lower resistance to blood flow in the lungs. These benefits were maintained for up to three months after a final treatment.

In addition to pemziviptadil, PhaseBio is also continuing clinical development of its lead product, bentracimab, designed to rapidly reverse the effects of certain other medications that prevent blood clotting. This allows for control of bleeding in people on such medications.