Combined Company WellFunded to Generate Data from Multiple Phase 2 Studies

Paul A. Friedman, M.D. Named Chairman and Chief Executive Officer of Combined Company

Companies to Host Conference Call and Webcast Today, April 14, at 8:30 AM ET

LEXINGTON, Mass. & FORT WASHINGTON, Pa.–(BUSINESS WIRE)–Synta Pharmaceuticals Corp. (“Synta”) (NASDAQ:SNTA) and Madrigal Pharmaceuticals, Inc., a privatelyheld company (“Madrigal”), today announced that they have entered into a definitive merger agreement (the “Merger”) under which Madrigal will merge with a wholly-owned subsidiary of Synta in an allstock transaction. The Merger will create a company focused on the development of novel small-molecule drugs addressing major unmet needs in cardiovascular-metabolic diseases and nonalcoholic steatohepatitis (NASH). Madrigal’s lead compound, MGL-3196, is a Phase 2ready once-daily, oral, liver-directed selective thyroid hormone receptorß (THRß) agonist for the treatment of NASH and heterozygous and homozygous familial hypercholesterolemia (HeFH, HoFH). Upon closing of the transaction, the combined company will be named Madrigal Pharmaceuticals, and Paul A. Friedman, M.D. will become Chairman and Chief Executive Officer.

Under the terms of the merger agreement, Synta will acquire all outstanding shares of Madrigal in exchange for approximately 253.9 million newly issued shares of Synta common stock. Upon completion of the proposed acquisition, it is anticipated that existing Synta shareholders will own 36.0% of the combined company and Madrigal shareholders will own 64.0% of the combined company. The transaction has been approved by the boards of directors of both companies and the shareholders of Madrigal. The merger is expected to close by the end of the third quarter of 2016, subject to customary closing conditions, including approval of the merger by the shareholders of Synta.

An investor syndicate that includes Bay City Capital, Fred Craves, Ph.D., Founder of Bay City Capital, and SQN LLC, a corporation held by Dr. Friedman and Rebecca Taub, M.D., has committed to invest up to $9 million in Madrigal prior to the closing of the Merger. The combined company intends to use these proceeds, in addition to Synta’s cash balance at the closing of the merger, to fund the development of MGL-3196 through Phase 2 clinical studies in NASH, HeFH and HoFH.

“Following an extensive review of strategic alternatives, Synta’s Board of Directors believes that a merger with Madrigal Pharmaceuticals offers shareholders the most compelling opportunity for enhancing long-term value,” said Keith R. Gollust, Chairman of Synta. “Madrigal’s lead compound, MGL-3196, is a selective THRß agonist with a unique lipid lowering profile that has been validated through early clinical and preclinical studies. The combined company will be well capitalized with a lead program that offers both a potentially substantial commercial opportunity in NASH, and an efficient clinical development plan with commercial potential in genetic lipid disorders.”

“MGL-3196 is designed to specifically target thyroid hormone beta receptors in the liver involved in metabolism and cholesterol regulation, and avoid side effects associated with thyroid hormone receptor activation outside the liver,” said Dr. Taub, Founder and Chief Executive Officer of Madrigal. “As a result, and because of MGL-3196’s observed high liver uptake and high ß-selectivity, it has a favorable safety profile and did not show adverse findings observed in chronic animal toxicology studies with a prior thyroid agonist. Madrigal has designed Phase 2 clinical programs to establish proof of concepts in both NASH and FH with data readouts for each program anticipated throughout 2017.”

MTS Health Partners, L.P. and ROTH Capital Partners, LLC served as financial advisors, and Mintz, Levin, Cohn, Ferris, Glovsky and Popeo, P.C. served as legal counsel to Synta and Stradling Yocca Carlson & Rauth, P.C. served as legal counsel to Madrigal with respect to the transaction.

Management and Organization

Effective with the signing of the merger agreement, Dr. Friedman has stepped down from Synta’s Board of Directors and will join Madrigal as an executive. Pursuant to the merger agreement, Dr. Friedman, the former Chief Executive Officer of Incyte Pharmaceuticals, will become Chairman and Chief Executive Officer of the combined company. Dr. Taub will assume the newly created role of Chief Medical Officer, Executive Vice President, Research & Development, following the closing of the Merger. Additionally, Marc Schneebaum, the current Chief Financial Officer of Synta, will continue as the Chief Financial Officer of the combined company. The board of directors of the combined company will be comprised of seven directors, including five directors of Madrigal: Dr. Friedman (Chairman); Dr. Taub; Fred Craves, Ph.D.; and two additional directors who will be designated, and one current director of Synta: Keith Gollust. There will also be one additional independent director to be agreed upon by Synta and Madrigal. The corporate headquarters will be located in the Philadelphia area.

About MGL-3196

MGL-3196 is an orally administered, small-molecule ßselective THR agonist being developed for nonalcoholic steatohepatitis (NASH) and heterozygous and homozygous familial hypercholesterolemia (FH) to lower LDL cholesterol, triglyceride levels and Lp(a). It was designed to specifically target receptors in the liver involved in metabolism and cholesterol regulation, and avoid side effects associated with thyroid hormone receptor activation outside the liver, including those mediated by THRα receptors. MGL-3196 is a potent regulator of hepatic triglyceride metabolism and cholesterol metabolism. In two week studies in humans MGL-3196 has been shown to reduce lipids: 30% for LDL cholesterol; 28% for non-high density lipoprotein (HDL) cholesterol; 24% for Apolipoprotein B, and up to 60% reduction in triglycerides. NASH in humans is a condition in which thyroid receptorß activity is diminished. MGL-3196 reduces lipotoxicity associated with NASH and in NASH preclinical models, MGL-3196 potently reduces hepatic triglycerides and markers of inflammation and fibrosis. MGL-3196, inlicensed from Roche Pharmaceuticals, has completed single, multi-ascending dose and drug interaction studies in humans in which the compound demonstrated a favorable safety profile at all doses tested.

Conference Call and Webcast

Synta and Madrigal will host a conference call and webcast slide presentation at 8:30 AM ET today to discuss the Merger. The conference call and presentation can be accessed by logging on to the “Investors” section of the Synta Pharmaceuticals website, www.syntapharma.com, prior to the event.