MEI's second go at cancer R&D flunks a Phase II MDS trial

MEI Pharma's ($MEIP) lead candidate failed to meet its primary goal in a Phase II study on myelodysplastic syndrome, a rare bone marrow disorder that often develops after cancer treatment, sending the biotech trawling for a positive spin on the data.

The company, formerly Marshall Edwards, tested a combination of its own pracinostat with Celgene's ($CELG) Vidaza in a placebo-controlled Phase II trial on 102 MDS sufferers. The addition of pracinostat made no difference in the rate of complete remission, the study's primary endpoint, compared with the older drug alone, MEI said, and the data on secondary goals aren't yet mature. On the safety side, fatigue, gastrointestinal toxicities and myelosuppresion were more common in the pracinostat arm and led to more frequent study dropouts, the company said.

The news sent MEI's shares down more than 60% on Monday morning.

Despite the failure, MEI isn't giving up on the effort, planning to unveil full results from the study at a scientific meeting this year and combing the results for silver linings. In the meantime, the company is holding off on any plans to start additional studies.

"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," CEO Daniel Gold said in a statement. "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."

And even if pracinostat comes up short in MDS, the company believes its drug may have a future in acute myeloid leukemia (AML). At December's American Society of Hematology meeting, MEI reported early signs of positive results among 33 evaluable patients in a Phase II AML trial, and rates of response and survival have improved ever since, the company said. MEI plans to present data from all 50 enrolled patients at the European Hematology Association meeting in June.

Pracinostat is MEI's second chance at oncology development after the 2010 failure of phenoxodiol, an ovarian cancer treatment, tanked its share value and spurred an overhaul. The company regrouped with the help of some private investors in 2012 and in-licensed pracinostat, an HDAC inhibitor, from Singapore's S*Bio.

- read the results