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WALTHAM, Mass., July 6, 2016 – Syndax Pharmaceuticals, Inc. (Nasdaq:SNDX), a clinical stage biopharmaceutical company focused on developing entinostat in multiple cancer indications, today announced that it has entered into an exclusive worldwide license agreement with UCB for UCB6352, an IND-ready anti-CSF-1R monoclonal antibody, which is expected to begin clinical trials in 2016.

WALTHAM, Mass., March 2, 2016 – Syndax Pharmaceuticals, Inc., a clinical stage biopharmaceutical company focused on developing entinostat in multiple cancer indications, announced today that it has priced its initial public offering of 4,400,000 shares of its common stock at a public offering price of $12.00 per share, for an aggregate offering of $52.8 million, before underwriting discounts, commissions and expenses. In addition, Syndax has granted the underwriters a 30-day option to purchase up to 660,000 additional shares of common stock at the initial offering price to cover overallotments, if any. All of the common stock is being offered by Syndax. The common stock will begin trading on The NASDAQ Global Select Market on March 3, 2016 under the trading symbol "SNDX." The offering is expected to close on March 8, 2016, subject to customary closing conditions.

Darmstadt, Germany, New York, US and Waltham, Mass., US, January 4, 2016 – Merck KGaA, Darmstadt, Germany, Pfizer and Syndax Pharmaceuticals, Inc. announced today that they have entered into a collaboration agreement to evaluate avelumab*, an investigational, fully human anti-PD-L1 IgG1 monoclonal antibody, in combination with Syndax’s entinostat, an investigational oral, small molecule that targets immune regulatory cells (myeloid-derived suppressor cells and regulatory Tcells), in patients with heavily pre-treated, recurrent ovarian cancer. Avelumab is currently under clinical investigation across a broad range of tumor types by the alliance between Merck KGaA, Darmstadt, Germany, and Pfizer. This is an exclusive agreement between the alliance and Syndax to study the combination of these two investigational agents in ovarian cancer. Syndax will be responsible for conducting the Phase Ib/II clinical trial in ovarian cancer.

WALTHAM, Mass., December 1, 2015 – -- Syndax Pharmaceuticals, Inc., a clinical stage biopharmaceutical company focused on developing entinostat as a combination therapy in multiple cancer indications, announced today the initiation of the entinostat clinical program in Japan by its partner Kyowa Hakko Kirin, Co., Ltd. Entinostat, an oral, small molecule drug candidate that targets both cancer cells and immune regulatory cells, is being developed by Syndax as an immuno-oncology therapeutic and evaluated as a treatment for advanced hormone receptor positive (HR+) breast cancer in an ongoing Phase 3 clinical trial (designated E2112) in the United States. In September 2013, entinostat was granted breakthrough therapy designation by the U.S. Food and Drug Administration in advanced HR+ breast cancer following positive results from the Phase 2b clinical trial, ENCORE-301.

WALTHAM, Mass., August 26, 2015 – Syndax Pharmaceuticals, Inc., a clinical-stage biopharmaceutical company focused on developing entinostat as a combination therapy in
multiple cancer indications, announced today that it has entered into a clinical collaboration with Genentech, a member of the Roche Group, to evaluate the safety, tolerability and preliminary
efficacy of Syndax’s entinostat, an oral small molecule that targets immune regulatory cells (myeloid-derived suppressor cells (MDSCs) and regulatory T cells (Tregs)), in combination with
Genentech’s atezolizumab (MPDL3280A), a fully humanized monoclonal antibody targeting protein programmed cell death ligand 1 (PD-L1), in patients with triple-negative breast cancer.
Triple-negative breast cancer is estimated to account for 10-20% of all diagnosed breast cancers and is characterized by a lack of expression of estrogen receptor (ER-), progesterone
receptor (PR-) and HER2 (HER2-) on the breast cancer cells.

WALTHAM, Mass., August 24, 2015 – Syndax Pharmaceuticals, Inc., a clinical stage biopharmaceutical company developing entinostat as a combination therapy in multiple cancer
indications, announced today that it has completed an $80 million Series C financing. The financing was led by Fidelity Management & Research Company and Delos Capital Fund LP
with participation from EcoR1 Capital, OrbiMed, Jennison Associates (on behalf of certain clients), Tavistock Life Sciences, Arrowpoint Partners, Cormorant Asset Management, BioMed
Ventures and undisclosed top-tier mutual funds, as well as existing investors Domain Associates, MPM Capital, RusnanoMedInvest (RMI) and Forward Ventures.

WALTHAM, Mass. and KENILWORTH, N.J., March 31, 2015 – Syndax Pharmaceuticals, Inc., and Merck (NYSE:MRK), known as MSD outside the United States and Canada, announced today that they have entered into a clinical trial collaboration to evaluate the safety and efficacy of combining Syndax’s entinostat, an investigational epigenetic therapy, with Merck’s KEYTRUDA® (pembrolizumab), the first anti-PD-1 therapy approved in the United States. The Phase 1b/2 study will evaluate this novel combination regimen in patients with either advanced non-small cell lung cancer (NSCLC) or melanoma. The study is expected to begin enrolling patients in the second half of 2015.

Tokyo, Japan, January 8, 2015 and Waltham, Mass., January 7, 2015 --- Kyowa Hakko Kirin Co., Ltd., (Headquarters: Chiyoda-ku, Tokyo; president and CEO: Nobuo Hanai, "Kyowa Hakko Kirin") and Syndax Pharmaceuticals, Inc., (Waltham, Mass.; president and CEO: Arlene M. Morris, “Syndax”) today jointly announced that the companies have entered into a license agreement for the exclusive rights to develop and commercialize entinostat in Japan and Korea. Entinostat is a Class I selective histone deacetylase (HDAC) inhibitor being developed by Syndax in the United States and Europe in combination with hormone therapy for advanced breast cancer and immune therapy combinations in solid tumors.