Mirati Presents Clinical Response Results of Mocetinostat in Combination with Azacitidine as a Treatment for MDS

SAN DIEGO, Dec. 9, 2013 /PRNewswire/ -- Mirati Therapeutics, Inc. ("Mirati") (NASDAQ: MRTX) today presented data at the 2013 American Society of Hematology (ASH) Annual Meeting demonstrating promising clinical response rates in patients with myelodysplastic syndromes (MDS) patients treated with mocetinostat in combination with azacitidine.  Separately, Mirati announced that it has dosed the first patients in its Phase 2 dose confirmation trial of mocetinostat in combination with azacitidine for the treatment of MDS.

In an analysis of an open-label, Phase 1/2 trial of 66 patients with MDS or acute myeloid leukemia (AML), researchers analyzed a subset of 22 patients with Intermediate and High Risk disease and baseline bone marrow blasts of 5 to 20 percent at screening, representing a population of patients with RAEB-1 or RAEB-2, a type of MDS that is associated with poor clinical outcomes. Of the 22 patients treated with mocetinostat plus azacitidine, 59 percent experienced an objective response. Median overall survival was 12.4 months.

"Patients diagnosed with MDS have few treatment options, and, despite the advances with the standard of care treatment of azacitidine alone, there remains an unmet medical need to improve patient outcome," said Dr. Guillermo Garcia-Manero, professor in the department of leukemia, division of cancer medicine and deputy chair of translational research, department of leukemia, division of cancer medicine (co-chair) at MD Anderson Cancer Center and the principal investigator of the study. "Building upon the experience with azacitidine, our data show that the addition of mocetinostat to azacitidine results in an encouraging objective response rate, and a randomized registration trial is the next logical step."

In the open-label dose confirmation trial that began dosing patients this month, Mirati's goal is to confirm the planned Phase 3 dose of mocetinostat in combination with full dose azacitidine to obtain additional information on clinical benefit of the combination. Data on dose confirmation will be available before the initiation of Phase 3, expected in the second half of 2014.

"The epigenetic mechanisms of mocetinostat, a histone deacetylase (HDAC) inhibitor, and hypomethylating agents such as azacitidine appear to be complementary and may result in improved outcomes for patients with MDS," noted Dr. Charles Baum, president and CEO of Mirati. "Our data support advancing our program toward the initiation of a Phase 3 registration study in 2014. We are also exploring the identification of subgroups of MDS and lymphoma patients that are likely to benefit from treatment with mocetinostat."

"The progression of mocetinostat to Phase 3 together with the advancement of the MGCD265 and MGCD516 programs should make 2014 a transformational year for Mirati," continued Dr. Baum.  

About Mocetinostat
Mocetinostat is an inhibitor of Class I HDACs currently in development for the treatment of patients with intermediate-2 and high-risk myelodysplastic syndromes (MDS). Mocetinostat has been studied in 13 clinical trials including 437 patients and the combination of mocetinostat and azacitidine showed a 93 percent disease control rate in 28 patients with MDS. Plans are underway for initiation of a Phase 3 trial of mocetinostat in combination with azacitidine in first line MDS patients in the second half of 2014. In addition, Mirati is exploring additional opportunities for mocetinostat in patients with lymphoma based on encouraging activity in early clinical studies.

About Mirati Therapeutics
Mirati Therapeutics is a targeted oncology company developing an advanced pipeline of breakthrough medicines for precisely defined patient populations. Mirati's approach combines the three most important factors in oncology drug development - drug candidates with complementary and compelling targets, creative and agile clinical development, and a highly accomplished precision medicine leadership team. The Mirati team is using its proven blueprint for developing targeted oncology medicines to advance and maximize the value of its pipeline of drug candidates, including MGCD265 and MGCD516, which are orally bioavailable, multi-targeted kinase inhibitors with distinct target profiles, and mocetinostat, an orally bio-available, spectrum-selective histone deacetylase inibitor. More information is available at www.mirati.com.

Forward-Looking Statements

Certain statements contained in this news release, other than statements of fact that are independently verifiable at the date hereof, may constitute forward-looking information and forward-looking statements (collectively "forward-looking statements" within the meaning of applicable securities laws). Such statements, based as they are on the current expectations of management of Mirati and upon what management believes to be reasonable assumptions based on information currently available to it, inherently involve numerous risks and uncertainties, known and unknown, many of which are beyond Mirati's control. Such statements can usually be identified by the use of words such as "may", "would", "believe", "intend", "plan", "anticipate", "estimate" and other similar terminology, or state that certain actions, events or results "may" or "would" be taken, occur or be achieved. Forward-looking statements in this release include, but are not limited to, statements regarding the promise of clinical responses to mocetinostat in combination with 5-azacitidine, and the timing of an initiation of a Phase 3 trial of mocetinostat.

Whether actual results and developments will conform with the expectations and predictions contained in this news release is subject to a number of risks, assumptions and uncertainties, many of which are beyond Mirati's control, and the effects of which can be difficult to predict. These risks include, but are not limited to, those inherent in drug development, market risks and uncertainties, unexpected cash requirements or changes in Mirati's business plans and other risks described in Mirati's filings with the Securities and Exchange Commission. In evaluating any forward-looking statements in this release, Mirati cautions readers not to place undue reliance on any forward-looking statements. Unless otherwise required by applicable securities laws, Mirati does not intend, nor does it undertake any obligation, to update or revise any forward-looking statements contained in this news release to reflect subsequent information, events, results or circumstances or otherwise.

SOURCE Mirati Therapeutics, Inc.