Rare Daily Staff

Pfizer said that the pivotal phase 3 study of its experimental sickle cell disease therapy rivipansel failed to meet its primary or key secondary efficacy endpoints.

The primary endpoint of the multicenter, randomized, double-blind, placebo-controlled, parallel-group RESET study was time to readiness-for-discharge and the key secondary efficacy endpoints were time-to-discharge, cumulative IV opioid consumption, and time to discontinuation of IV opioids. The study included patients aged six and older with sickle cell disease who were hospitalized for a vaso-occlusive crisis and required treatment with intravenous opioids.

Sickle cell disease (SCD) is a genetically caused blood disorder, characterized by acute vaso-occlusive crises (VOC) that result in debilitating pain. Worldwide, approximately 100 million people carry the SCD trait and an estimated five million live with the disease.

Treatment options for patients seeking medical care for a VOC are currently limited to symptomatic management with analgesics (including opioids and NSAIDs) and hydration, underscoring a significant need for new treatment options.

“We are disappointed with the results, as we have been working in close partnership with the SCD community to advance rivipansel as a potential treatment option for acute VOC,” said Brenda Cooperstone, senior vice president and chief development officer, Rare Disease, Pfizer Global Product Development. “We plan to share the study data at an upcoming scientific meeting as we want to ensure the learnings from this trial help inform future sickle cell programs that aim to improve care for SCD patients experiencing a VOC.”

Rivipansel is an investigational treatment for VOC in people with SCD that was in-licensed from GlycoMimetics. In 2011, GlycoMimetics and Pfizer entered into a worldwide license agreement for the development and, if approved by applicable regulatory authorities, commercialization of rivipansel. Since completion of the phase 2 clinical trial, Pfizer has been responsible for clinical development of rivipansel, including the current clinical trial.

“We recognize this is a significant setback for the SCD community, who are eagerly awaiting new treatment options, and we share in their disappointment,” said Freda Lewis-Hall, chief patient officer and executive vice president, Pfizer. “Many of us have witnessed first-hand the devastating impact of SCD on patients and their families, but we have also been moved by their incredible strength and bravery, and we will continue to support this courageous community.”

The RESET trial included 345 patients who were randomized with half to receive rivipansel and half to receive placebo, administered intravenously every 12 hours to a maximum of 15 doses. All study participants were followed for safety for 35 days after their last dose of study drug. Eligible patients who completed the RESET trial were able to enter an open-label extension study and receive rivipansel for subsequent VOC episodes over an 18-month period.

Detailed analyses of Pfizer’s late-stage study, including additional data on efficacy and safety endpoints, which are not available at this time, will be submitted for presentation at a future scientific meeting.

Photo: Brenda Cooperstone, senior vice president and chief development officer, Rare Disease, Pfizer Global Product Development

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