MEI Pharma, Inc. announced that an independent Safety Review Committee completed its pre-specified review of the first cohort of six evaluable patients in a Phase Ib, open-label, dose-escalation study of the Company's investigational drug candidate ME-401, a potent and selective oral PI3K delta inhibitor, in relapsed/refractory chronic lymphocytic leukemia (CLL) and follicular lymphoma. Based on its review of the safety and efficacy data, the Safety Review Committee declared a minimum biologically effective dose (mBED) for ME-401 at the starting dose of 60 mg and recommended escalation to a 120 mg dose cohort. According to the study protocol, the mBED is defined as a dose that is safe and achieves a response in at least three of six patients. Response assessments are based on criteria of the International Workshop on Chronic Lymphocytic Leukemia for patients with CLL or the Lugano Classification for patients with follicular lymphoma. Response is initially assessed after 8 weeks of therapy. To date, all six patients have been on study for a minimum of 10 weeks (range, 10-28 weeks). There have been no reports of ALT/AST elevations, colitis or pneumonitis, events commonly reported with other drugs in this class. One patient in the study experienced grade 3 neutropenia that was considered related to study drug. All other adverse events reported were grades 1 or 2. No patients have discontinued due to adverse events. Full data will be submitted for presentation at an upcoming scientific meeting.