PhaseBio Reports Positive Effects of PB1046 Therapy in PAH Patient in Case Study

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by Vanessa Pataia |

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PB1046 case study

The biopharmaceutical PhaseBio announced positive results from a case study involving a patient with pulmonary arterial hypertension (PAH) who received treatment with PB1046, a new therapy using the company’s proprietary technology platform.

PB1046 is a therapy created from a combination of two other compounds: vasoactive intestinal peptide (VIP) and PhaseBio’s elastin-like polypeptide (ELP) biopolymer.

Human VIP is a neurohormone — a hormone produced by nerve cells — that relaxes the muscles surrounding the blood vessels and allows them to dilate, which helps to increase blood flow. When injected into circulation in the body, normal VIP is degraded within minutes. However, when combined with ELP, as in PB1046, it is stable for up to 120 hours. 

Apart from inducing vasodilation, or the widening of blood vessels, PB1046 also is expected to stop the abnormal restructuring of blood vessels that occurs in people with PAH.

Clinical trials have shown that PB1046 is stable for a long time in blood circulation, allowing it to slowly be absorbed by the body over several days. These features make it possible for this medication to be injected under the skin (subcutaneously) only once per week.

The case report was presented by PhaseBio at the 14th Pulmonary Vascular Research Institute (PVRI) World Congress, held Jan. 30 through Feb. 2 in Lima, Peru.

The patient was part of a Phase 1b/2a pilot study assessing PB1046’s multi-dose safety and pharmacokinetics — how the human body processes the therapy. The study included three people with PAH who had hemodynamic monitors — the CardioMEMS HF system — permanently implanted in their pulmonary arteries.

The CardioMEMS HF system takes continuous measurements of a person’s heart rate, and the systolic and diastolic blood pressures of the pulmonary artery, which are known as hemodynamic parameters. This system allowed an investigation into the effects of taking weekly PB1046 injections, for eight weeks, on the hemodynamic parameters of the three participants. 

Previous results showed that the tested PB1046 doses had a favorable safety profile. The injections were well-tolerated by the three patients, who reported only some redness around the injection area, and no serious adverse events related to the medication.

The patient now described in the case report received an extended PB1046 treatment for a total of 18 months, given the continued improvements seen in his hemodynamic parameters.

These improvements included a decrease in mean blood pressure of the pulmonary artery, and lower resistance to blood flow in the lungs. The treatment also increased the patient’s stroke volume — the amount of blood the heart pumps out to the body in one heartbeat — and his cardiac output, or the amount of blood pumped by the heart in one minute, without raising his heart rate. This means that the heart did not have to work harder in order to increase the circulation of blood in the body.

Additionally, these positive effects were maintained for up to three months after the patient took the last dose of PB1046, the researchers said.

“We were pleased to see sustained positive long-term effects in an adult patient with PAH who had been treated with PB1046,” Raymond Benza, MD, cardiologist at the Allegheny Health Network, said in a press release

“We believe these data validate the continued evaluation of PB1046 in the ongoing Phase 2b clinical trial and underscore its potential to be a once-weekly treatment for PAH,” Benza said.

Thus far, PB1046 has been given to more than 70 patients with hypertension or a history of cardiovascular disease in three Phase 1/2 clinical trials conducted in the U.S. There have been no drug-related serious adverse events reported.

A Conversation With Rare Disease Advocates