[caption id="attachment_9277" align="aligncenter" width="747"] Press Release[/caption]

Transformational Transaction Provides Key Program in First-Line Acute Myeloid Leukemia with Fast Track and Orphan Drug Designations and Potential Utility as a Platform Technology?

Phase II Randomized Data Presented at?ASCO?2019 Demonstrated Compelling Complete Response Rates, Event-Free Survival, and Overall Survival in Combination with Standard Chemo Compared to Standard Chemo Alone

???????Company Plans to Initiate Phase 3 Registrational Trial in mid-2020 ? Conference Call at?8:30 a.m. ET?Today

DURHAM, N.C.,?July 31, 2019?(GLOBE NEWSWIRE) --?Chimerix?(NASDAQ: CMRX), today announced the completion of an exclusive worldwide license of CX-01 from?Cantex Pharmaceuticals, Inc.Chimerix?intends to move quickly into Phase 3 development of CX-01 for the treatment of Acute Myeloid Leukemia (AML) in the first-line setting. CX-01 has received Fast Track and Orphan Drug Designations from the?U.S. Food and Drug Administration?for the treatment of AML. ?We are pleased to have made such rapid progress in repositioning the company and transforming our pipeline with this important cancer therapy. We are excited to advance this promising product candidate in AML as it has shown compelling activity across multiple endpoints in first-line patients as opposed to later lines of therapy where most of the recent advances in this disease area have occurred. With more than 21,000 new cases of AML diagnosed annually in the U.S. alone and a five-year survival rate of less than 30%, the patient need is clear. CX-01?s mechanism of action, targeting multiple proteins involved in protecting and supporting the growth of cancer cells, provides opportunities for potential development across a range of hematologic malignancies,? stated?Mike Sherman, Chief Executive Officer of?Chimerix. ?This transaction exemplifies our commitment to pursuing and accelerating programs where we can quickly address unmet patient needs with a meaningful clinical benefit.? ?While several new agents have been recently approved for AML, a backbone of cytotoxic chemotherapy continues to be necessary for treatment with curative intent. If our results are confirmed, combining CX-01 with chemotherapy has the potential to have a significant impact on the outcomes of patients suffering from one of the most challenging hematologic malignancies,? said?Paul Shami, MD, clinical investigator at?Huntsman Cancer Institute?and Professor of Medicine at the?University of Utah. CX-01 is a new chemical entity derived from unfractionated heparin with very low anticoagulant activity. ?CX-01 targets key protein pathways important for AML blast cell migration to the bone marrow and retention of these cells in the marrow where they are protected from chemotherapy. CX-01 also binds with proteins involved in chemotherapy resistance and the delay in platelet recovery after chemotherapy. Together, these activities are understood to sensitize AML blasts to chemotherapy and improve clinical responses. These mechanisms of action support the potential for development in myelodysplastic syndrome, multiple myeloma, and lymphomas. In a recently completed Phase II study, 75 patients over 60 years of age with newly diagnosed AML were ?randomized 1:1:1 to one of two doses of CX-01 (0.125 mg/kg/hr or 0.250 mg/kg/hr) plus standard 7+3 chemotherapy (7 days of cytarabine, 3 days of anthracycline) or to the control arm of standard 7+3 chemotherapy alone. Data presented at the 2019?ASCO?conference indicated an advantage across multiple endpoints for patients treated with 0.25 mg/kg/hr CX-01. In the evaluable patient population, results of the 0.25 mg/kg/hr CX-01 arm compared favorably to the control arm: complete response rate (complete response or complete response without complete hematologic recovery) of 89% vs. 58% (p=0.03), median event-free survival of 23.4 months vs. 9.0 months (p=0.011), and median overall survival which had not yet been reached in the CX-01 arm vs. 11.2 months (p=0.042). These data were consistent with a single arm pilot study of first line therapy in patients with AML (n=12), including a complete response rate of 92%. CX-01 was well tolerated with adverse events similar across all treatment arms.? The most common serious adverse event was febrile neutropenia with three cases in each CX-01 treatment group and one case in the control group. Stephen Marcus, M.D., CEO of Cantex, stated, ?We are very pleased to be partnering with?Chimerix?and their world-class scientists. We believe that?Chimerix?management?s track record in developing novel cancer therapeutics makes?Chimerix?the perfect partner to aggressively advance the development of CX-01 for the treatment of AML and other hematologic malignancies.? Transaction Terms Under the terms of the agreement,?Chimerix?has exclusive worldwide rights to develop and commercialize CX-01.?Chimerix?will make an upfront payment of?$30 million?to Cantex. In addition,?Chimerix?has issued 10 million shares of?Chimerix?common stock to Cantex. Cantex is eligible for regulatory and commercial milestones of up to?$587.5 million, and tiered royalties starting at 10%.