Vepoloxamer Does Not Meet Primary Endpoint in Phase III Study in Patients With Sickle Cell Disease

In the phase III EPIC (Evaluation of Purified Poloxamer 188 [MST-188] In Crisis) study, vepoloxamer, an investigational therapy for sickle cell disease (SCD), did not reduce the mean duration of vaso-occlusive crisis (VOC; the study’s primary endpoint) compared with placebo (82 hours vs. 78 hours, respectively; p=0.09).

There also were no statistically significant differences in secondary endpoints, including the rate of re-hospitalization for VOC and occurrence of acute chest syndrome, according to a press release from Mast Therapeutics, Inc., the drug’s manufacturer.

Vepoloxamer appeared to be well tolerated in this patient population, with no statistically significant differences in treatment-related adverse events between vepoloxamer and placebo. No deaths occurred during the study.

EPIC was a randomized, double-blind, two-arm, placebo-controlled trial that assessed outcomes in 388 patients with SCD (4-46 years of age) who were hospitalized for acute pain and required treatment with parenteral opioid analgesia. The mean patient age was 15 years, and most patients (71%) were <18 years old. Many patients (61%) were concurrently receiving hydroxyurea.

Patients were randomized to receive placebo or vepoloxamer 100 mg/kg administered intravenously as a one-hour infusion, followed by continuous maintenance infusion (30 mg/kg/hour) for at least 12 hours (up to 48 hours) or placebo.

In a statement to ASH Clinical News, a representative from Mast Therapeutics, Inc., said, “While it is disappointing that vepoloxamer was not shown to be effective in this study, we have confidence that the study was well performed and represents the best contemporaneous dataset documenting VOC in SCD. We are confident the data will provide important insights into mechanisms of injury and more complete information on a well characterized, international cohort of patients on the natural history of disease and course of VOC. We firmly believe the dataset would be useful in future interventional trial design.”

Source: Mast Therapeutics press release, September 20, 2016.