Ambit Biosciences Provides Regulatory Update Following FDA Meeting Regarding Quizartinib; Says Company May Have to Run Another Trial

Ambit Biosciences (Nasdaq: AMBI), abiopharmaceutical company focused on discovery and development of drugstargeting unmet needs in oncology, autoimmune and inflammatory disease,today announced a regulatory update after receiving feedback from the U.S.Food and Drug Administration (FDA) on the development of quizartinib(AC220), the Company's lead drug candidate, for the treatment ofrelapsed/refractory acute myeloid leukemia (AML). Based on feedback from the FDA, the Company continues to move forward withits baseline plan to conduct a randomized, controlled Phase 3 clinical trialin relapsed/refractory FLT3-ITD positive AML patients with an overallsurvival endpoint as the basis for the potential initial approval ofquizartinib. The Company is continuing to work with the FDA to refine theappropriate starting dose for the Phase 3 trial. The Company has been in dialogue with the FDA related to acceptance of anovel surrogate endpoint that could support accelerated approval based uponthe results of the Company's Phase 2 and Phase 2b trials. The FDA informedthe Company it does not agree that complete remission with incompletehematologic recovery (CRi) represents a surrogate endpoint reasonably likelyto predict clinical benefit. Based on the FDA's current position, theCompany does not plan at this time to submit a NDA for accelerated approvalof quizartinib based on the Phase 2 and 2b clinical trial data. "We remain committed to moving quizartinib through its late stagedevelopment as expeditiously as possible, given the limited treatmentoptions for FLT3 ITD positive AML patients who have relapsed or who arerefractory to prior treatments. We will continue to work with the clinicalcommunity and the FDA to achieve this goal," said Michael A. Martino,President and CEO of Ambit. "We believe that our data demonstrates theclinical value and benefit of quizartinib for patients in an area of clearand high unmet medical need. We look forward to presenting our data at ASHnext week and anticipate a high level of clinical enthusiasm." Data from quizartinib studies will be presented at the ASH 55(th) AnnualMeeting at the Ernest Morial Convention Center in New Orleans, LA onDecember 9, 2013. Oral Presentations: Results of Phase 2 Randomized, Open-Label, Study of Lower Doses ofQuizartinib in Subjects with FLT3-ITD Positive Relapsed Acute MyeloidLeukemia (AML): The purpose of this study is to assess the efficacy andsafety of lower doses of quizartinib in the treatment of patients 18-yearsor older with relapsed/refractory FLT3 ITD positive AML to further improvethe benefit:risk assessment of quizartinib. The data will be presented byDr. Jorge Cortes at 3:00 pm CT on Monday, December 9, in the La NouvelleBallroom C. Quizartinib Can Be Safely Combined With ConventionalChemotherapy In Older Patients With Newly Diagnosed Acute Myeloid Leukemia:Experience From The AML Pilot Trial: This is the first presentation ofquizartinib use in combination with chemotherapy in newly diagnosed olderAML patients, testing the feasibility and dose which could be givensequentially following conventional chemotherapy in patients over the age of60 years. The data will be presented by Dr. Alan Burnett at 5:15 pm CT onMonday, December 9, in the La Nouvelle Ballroom C. Results of Phase 1 Studyof Quizartinib In Combination with Induction and Consolidation Chemotherapyin Younger Patients with Newly Diagnosed Acute Myeloid Leukemia: This doseescalation study is the first to report data on quizartinib in combinationwith standard induction and consolidation chemotherapy in patients betweenthe ages of 18 to 60-years with newly diagnosed AML, regardless of FLT3status. The data will be presented by Dr. Jessica Altman at 5:30 pm CT onMonday, December 9, in the La Nouvelle Ballroom C. A Phase I Study ofQuizartinib in Combination with Cytarabine and Etoposide inRelapsed/Refractory Childhood ALL and AML: A Therapeutic Advances inChildhood Leukemia & Lymphoma Study: This was the first clinical trial usingquizartinib in children between the ages of 1 month and 21-years withrelapsed/refractory AML or MLL-rearranged ALL. The data will be presented byDr. Todd Cooper at 5:45 pm CT on Monday, December 9, in the La NouvelleBallroom C. Poster presentations from the investigators from The Sidney KimmelComprehensive Cancer Center, Johns Hopkins Hospital: Activities Of Commonly Used Tyrosine Kinase Inhibitors Against Wild Typec-KIT And Potential Impact On Normal Hematopoiesis. Session Name: MolecularPharmacology, Drug Resistance: Poster III. Presentation on Monday, December9, 2013 from 6:00 - 8:00 pm in Hall E. The Combination Of FLT3 InhibitionAnd Hypomethylation Confers Synergistic Antileukemic Effects On FLT3-ITDPositive AML Cell Lines And Primary Cells: Session Name: Acute MyeloidLeukemia: Therapy, excluding Transplantation: Poster III. Presentation onMonday, December 9, 2013 from 6:00 - 8:00 pm in Hall E. The abstracts can be accessed on the ASH website at http://hematology.org. Conference Call and Webcast A conference call to discuss the FDA response will be hosted by the Ambitmanagement team webcast live tomorrow morning, Wednesday, December 4, 2013,at 9:00 am ET or 6:00 am PT and can be accessed by dialing 877-280-4954.Please specify that you would like to join the "Ambit Biosciences FDA UpdateConference Call" and reference conference passcode 75822572. If you areunable to listen to the live webcast, a teleconference replay will beavailable through Wednesday, December 11, 2013. Interested parties canaccess the replay by dialing 888-286-8010 and entering the conferencepasscode 13352784. The conference call webcast is accessible through the "Investors & Media"section of the Ambit website at http://www.ambitbio.com. An online replaywill be available following the initial broadcast until Thursday, December19, 2013. Please visit Ambit's website several minutes prior to the startof the broadcast to ensure adequate time for any software download that maybe necessary. About Ambit Biosciences Ambit is a biopharmaceutical company focused on the discovery, developmentand commercialization of drugs to treat unmet medical needs in oncology,autoimmune and inflammatory diseases by inhibiting kinases that areimportant drivers for those diseases. Ambit's lead drug candidate,quizartinib (AC220), is a once-daily, orally-administered potent andselective, inhibitor of FMS-like tyrosine kinase-3 (FLT3) and is currentlyunder clinical development in patients with relapsed/refractory AML and innewly diagnosed AML patients in combination with chemotherapy as well asmaintenance following a hematopoietic stem cell transplantation (HSCT). Inaddition to quizartinib, Ambit's clinical pipeline includes AC410, an oralJAK2 inhibitor, and CEP-32496, a BRAF inhibitor licensed to TevaPharmaceutical Industries Ltd. Ambit's preclinical portfolio includes aproprietary CSF1R inhibitor program. Forward-Looking Statements Statements contained in this press release regarding matters that are nothistorical facts are "forward-looking statements" within the meaning of thePrivate Securities Litigation Reform Act of 1995, including statementsassociated with Ambit's expectations regarding future development andtherapeutic potential of quizartinib and Ambit's other drug candidates,progress and timing of Ambit's drug development programs, including thesubmission of regulatory filings and planned discussions with regulatorybodies, plans regarding future clinical trials of quizartinib, including thestarting dose for the Phase 3 clinical trial, and Ambit's other drugcandidates, the progress and expected timing of clinical trials includingthe timing of initiation of the Phase 3 clinical trial, the presentation ofdata from clinical trials, the clinical benefits to be derived fromquizartinib and Ambit's other drug candidates and the regulatory approvalpath for quizartinib. Because such statements are subject to risks anduncertainties, actual results may differ materially from those expressed orimplied by such forward-looking statements. Words such as "plans,""expects," "anticipates," "hopes", "may," "will," "goal," "potential" andsimilar expressions are intended to identify forward-looking statements.These forward-looking statements are based upon Ambit's current expectationsand involve assumptions that may never materialize or may prove to beincorrect. Actual results and the timing of events could differ materiallyfrom those anticipated in such forward-looking statements as a result ofvarious risks and uncertainties, which include, without limitation, risksassociated with the process of discovering, developing and commercializingdrugs that are safe and effective for use as human therapeutics, and in theendeavor of building a business around such drugs. These and other risksconcerning Ambit's programs are described in additional detail in Ambit'sSEC filings. All forward-looking statements contained in this press releasespeak only as of the date on which they were made. Ambit undertakes noobligation to update such statements to reflect events that occur orcircumstances that exist after the date on which they were made.