MEI Pharma Reports Updated Results from Phase II Study of Pracinostat and Azacitidine in Elderly Patients with Newly Diagnosed Acute Myeloid Leukemia

SAN DIEGO, June 12, 2015 /PRNewswire/ -- MEI Pharma, Inc. MEIP, an oncology company focused on the clinical development of novel therapies for cancer, announced updated results from a Phase II study of its investigational drug candidate Pracinostat in combination with azacitidine (marketed as Vidaza^®) in elderly patients with newly diagnosed acute myeloid leukemia (AML). Data from 50 patients treated at 15 centers are being presented at the European Hematology Association (EHA) Annual Congress in Vienna. A copy of the poster, entitled "Updated Results from a Phase 2 Study of Pracinostat in Combination with Azacitidine in Elderly Patients with Acute Myeloid Leukemia," is now available at www.meipharma.com.

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To date, 27 of 50 patients (54%) have achieved the primary endpoint of complete response (CR) plus complete response with incomplete blood count recovery (CRi) plus morphologic leukemia-free state (MLFS), including 16 patients (32%) who achieved a CR. The response rate from this study compares favorably with previous studies of azacitidine alone in this population¹. Most responses occur within the first two cycles and continue to improve with ongoing therapy.

Median overall survival has not yet been reached in the study, with 32 patients (64%) still being followed (range, 6-15 months). Survival of patients with intermediate-risk cytogenetic abnormalities appears greater than that for patients with high-risk cytogenetics, though neither subset of patients has reached median survival. The 60-day mortality rate, often used as a benchmark in AML clinical studies, was 10% (5 of 50).

Pracinostat in combination with azacitidine was well tolerated in this population of elderly AML patients. The most common treatment-emergent adverse events (AEs) included febrile neutropenia, thrombocytopenia, nausea and fatigue. AEs resulting in dose reductions were frequently due to disease under study. Nearly half of the patients (22 of 50) to date have received study drug beyond six months, reflecting long-term tolerability.

"The combination of Pracinostat and azacitidine continues to demonstrate compelling clinical activity in these elderly patients with newly diagnosed AML," said Daniel P. Gold, Ph.D., President and Chief Executive Officer of MEI Pharma. "While the overall survival trend in this study is encouraging, we believe that longer follow-up is needed to gain an accurate survival estimate. Ultimately, this survival estimate will be critical in determining the development path forward for this combination. We look forward to providing an update when these data mature, which we expect to occur later this year."

About Pracinostat

Pracinostat is an orally available inhibitor of a group of enzymes called histone deacetylases, or HDACs. HDACs belong to a larger set of proteins collectively known as epigenetic regulators that can alter gene expression by chemically modifying DNA or its associated chromosomal proteins. Abnormal activity of these regulators is believed to play an important role in cancer and other diseases. Pracinostat has been tested in multiple Phase I and Phase II clinical studies in advanced hematologic diseases and solid tumor indications with side effects often associated with drugs of this class, the most frequent of which is fatigue. The results of these studies also suggest that Pracinostat has potential best-in-class pharmacokinetic properties when compared to other oral HDAC inhibitors.

MEI Pharma owns exclusive worldwide rights to Pracinostat.

About AML

Acute myeloid leukemia (also known as acute myelogenous leukemia) is the most common acute leukemia affecting adults, and its incidence is expected to increase as the population ages. The American Cancer Society estimates about 20,830 new cases of AML per year in the U.S., with an average age of about 67 years. Treatment options for AML remain virtually unchanged over the past 30 years. Front line treatment consists primarily of chemotherapy, while the National Comprehensive Cancer Network (NCCN) Clinical Practice Guidelines in Oncology recommend azacitidine or decitabine (marketed as Dacogen^®) as low intensity treatment options for AML patients over the age of 60 who are unsuitable for induction chemotherapy.

About MEI Pharma

MEI Pharma, Inc. MEIP is a San Diego-based oncology company focused on the clinical development of novel therapies for cancer. The Company's portfolio of drug candidates includes Pracinostat, a potential best-in-class, oral HDAC inhibitor currently in development for the treatment of advanced hematologic diseases. The Company is also developing ME-344, a mitochondrial inhibitor currently in a Phase Ib study in combination with topotecan in patients with small cell lung or ovarian cancer who failed initial therapy. In addition, the Company expects to initiate a first-in-human study of PWT143, a highly selective PI3K delta inhibitor, in mid-2015. For more information, please visit www.meipharma.com.

Under U.S. law, a new drug cannot be marketed until it has been investigated in clinical studies and approved by the FDA as being safe and effective for the intended use. Statements included in this press release that are not historical in nature are "forward-looking statements" within the meaning of the "safe harbor" provisions of the Private Securities Litigation Reform Act of 1995. You should be aware that our actual results could differ materially from those contained in the forward-looking statements, which are based on management's current expectations and are subject to a number of risks and uncertainties, including, but not limited to, our failure to successfully commercialize our product candidates; costs and delays in the development and/or FDA approval, or the failure to obtain such approval, of our product candidates; uncertainties or differences in interpretation in clinical trial results; our inability to maintain or enter into, and the risks resulting from our dependence upon, collaboration or contractual arrangements necessary for the development, manufacture, commercialization, marketing, sales and distribution of any products; competitive factors; our inability to protect our patents or proprietary rights and obtain necessary rights to third party patents and intellectual property to operate our business; our inability to operate our business without infringing the patents and proprietary rights of others; general economic conditions; the failure of any products to gain market acceptance; our inability to obtain any additional required financing; technological changes; government regulation; changes in industry practice; and one-time events. We do not intend to update any of these factors or to publicly announce the results of any revisions to these forward-looking statements.

¹ Dombret H et al. International phase 3 study of azacitidine vs conventional care regimens in older patients with newly diagnosed AML with >30% blasts. Blood. 2015 May 18.

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SOURCE MEI Pharma, Inc.