MEI Pharma reports top-line results from Pracinostat Phase II study in patients with high-risk MDS

MEI Pharma, Inc. (Nasdaq: MEIP), an oncology company focused on the clinical development of novel therapies for cancer, today announced top-line data from a randomized Phase II clinical study of its investigational drug candidate Pracinostat in combination with azacitidine in patients with previously untreated intermediate-2 or high-risk myelodysplastic syndrome (MDS). The double-blind, placebo-controlled study enrolled a total of 102 patients, randomized one-to-one, at 19 sites in the U.S.

According to the top-line data, the combination of Pracinostat and azacitidine showed no difference in the rate of complete remission (CR), the study's primary endpoint, compared to azacitidine alone. Data from event-driven endpoints, including duration of response, event and progression free survival and overall survival, are immature and will require longer follow-up in order to achieve meaningful conclusions. There were no new or unexpected toxicities observed in the study. Fatigue, gastrointestinal toxicities and myelosuppresion occurred more frequently in the combination group and resulted in a higher rate of drug discontinuations compared to azacitidine alone. The Company expects to present full results of the study at a scientific meeting later this year.

"Our goal when we initiated this study was to build on prior data and rigorously assess the clinical benefit of Pracinostat in combination with azacitidine in MDS," said Daniel P. Gold, Ph.D., President and Chief Executive Officer of MEI Pharma. "While we are disappointed with these top-line response data, we are diligently analyzing the entire data set as well as subsets from this study. Specifically, we are trying to fully assess the impacts of discontinuations on clinically important efficacy outcomes, including duration of response, event and progression free survival and overall survival. These findings will be important to inform the future development path for Pracinostat."

At the American Society of Hematology (ASH) Annual Meeting In December 2014, the company reported significant clinical activity from 33 evaluable patients in an open-label, single-arm Phase II study of Pracinostat and azacitidine in elderly patients with newly diagnosed acute myeloid leukemia (AML). Further follow-up indicates that the response rate and overall survival of these patients continued to increase. To date, 12 patients have been on study for more than six months, including five who have surpassed one year. Data from all 50 patients enrolled in this study have been submitted for presentation at the European Hematology Association (EHA) Annual Congress in June 2015.

"AML represents another important component of our Pracinostat development strategy," continued Dr. Gold. "We remain encouraged by the durable responses and long-term tolerability observed in our ongoing Phase II study and will continue to monitor these patients closely to get a better estimate of the survival benefit. However, we do not intend to initiate any further studies of Pracinostat and azacitidine until we have gained a more complete understanding of the totality of clinical data surrounding the combination. We expect to be in a position to share more information regarding these findings and future development plans for Pracinostat later this year."

SOURCE MEI Pharma, Inc.