Chimerix Provides Clinical Development Update

Chimerix, Inc. CMRX, a biopharmaceutical company developing novel, oral antivirals in areas of high unmet medical need, today provided an update on the clinical development of its investigational broad-spectrum antiviral, brincidofovir, for the prevention of cytomegalovirus (CMV) and the treatment of adenovirus infection. Brincidofovir for CMV As announced earlier this summer, the SUPPRESS trial evaluating brincidofovir for the prevention of clinically significant CMV infection in those who have recently undergone hematopoietic cell transplant (HCT), or bone marrow transplant, is fully enrolled, meeting its target of 450 patients. In addition to evaluating the primary endpoint of preventing CMV, this study also includes secondary endpoints for the prevention of clinically relevant infections with other DNA viruses that often coexist in immunocompromised patients, such as adenovirus, Epstein-Barr virus (EBV) and BK virus. Chimerix anticipates reporting topline results from SUPPRESS in early 2016. If positive, the results of this placebo-controlled Phase 3 trial will provide the basis for the anticipated regulatory filing of brincidofovir for the prevention of CMV. There is currently no approved therapy for the prevention of CMV in HCT recipients, which is associated with significant morbidity in this patient population. Brincidofovir for Adenovirus Chimerix recently announced the completed enrollment of more than 200 patients in AdVise, the open-label trial of brincidofovir for the treatment of disseminated or localized adenovirus infection in patients at increased risk of rapid progression to disseminated disease. In recent discussions with the Food and Drug Administration (FDA), the FDA has recommended that the initial New Drug Application for brincidofovir be reviewed for efficacy based only on data from SUPPRESS. Chimerix will continue to prepare data from the AdVise trial, including its historical matched controls, to review with the FDA to determine the regulatory pathway for the treatment of adenovirus. With no approved treatment, short-term mortality rates for adenovirus have been reported as high as 80 percent in patients with disseminated disease. "As we look ahead to the results of the SUPPRESS trial, we are working closely with the FDA as we prepare the regulatory submission of brincidofovir for CMV," said M. Michelle Berrey, M.D., M.P.H., President and CEO of Chimerix. "Brincidofovir has the potential to be the first product indicated for the prevention of CMV in HCT recipients, which would be paradigm-changing in managing HCT patients after transplant. We also remain committed to continuing our groundbreaking work studying brincidofovir for the treatment of adenovirus and we look forward to determining an appropriate regulatory pathway to potentially bring a much-needed treatment option to a fragile patient population." Brincidofovir in Kidney Transplants The planned Phase 3 SUSTAIN and SURPASS trials of brincidofovir for the prevention of CMV in kidney transplant patients are scheduled to initiate enrollment in the second half of 2015. SUSTAIN will evaluate 750 patients who are CMV seronegative (R-) who receive a CMV positive (D+) kidney. SURPASS will evaluate 520 CMV seropositive (R+) kidney transplant recipients. CMV is a significant cause of morbidity in kidney transplant patients. While graft survival has improved, ten-year graft survival rates are still lower than 50 percent. In addition, approximately one fifth of kidney transplant recipients have BK viremia in the first year post-transplant; BK viremia-associated disease results in graft loss in more than two thirds of affected patients. Together, SURPASS and SUSTAIN provide an opportunity to demonstrate the ability of brincidofovir to prevent CMV disease versus the current standard of care, as well as show a potential positive impact of brincidofovir on BK virus and improved graft function. About Hematopoietic Cell Transplantation More than 70,000 hematopoietic cell transplants are performed each year worldwide, most frequently to treat patients with certain cancers of the blood and bone marrow, or to address genetic diseases. Due to chemotherapy and the immune suppression associated with HCT, patients are highly susceptible to viral, bacterial and fungal infections. These complications are a significant cause of morbidity and mortality in the months following the transplant, and too often the high risk of infection in the first year after transplant results in patients and their families deciding not to undergo a potentially curative transplant. About Cytomegalovirus Cytomegalovirus is a member of the herpesvirus family and remains a significant cause of viral infections in transplant recipients. A majority of adults in the U.S. have evidence of a prior infection with CMV which establishes a dormant or latent infection that cannot be cleared; most individuals have an immune system that is able to prevent CMV from reactivating and causing disease. In individuals with weakened immune systems - such as transplant recipients - CMV commonly reactivates during the first weeks following the transplant, leading to infection of the lungs or other organ system and increasing the risk of other viral, bacterial and fungal infections. No therapies are approved for the prevention of CMV in HCT recipients because of known toxicities associated with available CMV antivirals, including bone marrow suppression and renal impairment.