US-based biopharmaceutical company Mast Therapeutics has reported top-line data from its Phase III EPIC study of vepoloxamer (MST-188) to treat patients with sickle cell disease experiencing vaso-occlusive crisis (VOC).

Vepoloxamer is a purified poloxamer 188, a nonionic, block copolymer featuring a central linear chain of hydrophobic polyoxypropylene with linear hydrophilic polyoxyethylene chains on both sides.

The Phase III EPIC study was designed as a randomised, double-blind, two-arm, placebo-controlled trial and involved 388 patients suffering from sickle cell disease who were hospitalised for acute pain typical of vaso-occlusive crisis and who required treatment with parenteral opioid analgesia.

The study failed to meet its primary efficacy endpoint of assessing the efficacy of the company’s new drug in reducing the duration of vaso-occlusive crisis, measured from the time of randomisation to the time when the patient was administered with the last dose of parenteral opioid analgesia for the treatment of vaso-occlusive crisis prior to hospital discharge.

"No significant differences were observed in the treatment group administered with vepoloxamer."

No significant differences were observed in the treatment group administered with vepoloxamer.

The study's secondary endpoints were to compare the re-hospitalisation rates for vaso-occlusive crisis within 14 days of initial hospital discharge and the occurrence of acute chest syndrome within 120 hours of randomisation between the treatment and control groups.

Mast Therapeutics CEO Brian Culley said: "We are exceedingly disappointed with these top-line results.

“While clearly not the outcome we wanted, we believe the insights and data from the largest placebo-controlled clinical trial ever completed in sickle cell disease will substantially advance the understanding of vaso-occlusive crisis and the still maturing clinical science necessary to support the development of new therapeutics for this debilitating disease.”

Culley stated that based on the topline data, the company will stall all clinical development involving vepoloxamer, which includes an interim analysis of the ongoing heart failure trial of vepoloxamer.