[Updated 2/22/16, 11:43 am. See below. ] Chimerix is shutting down two late-stage trials for a drug meant to prevent infections in kidney transplant patients, a decision that follows the drug’s recent Phase 3 failure in people who have received stem cell transplants.
Durham, NC-based Chimerix (NASDAQ: [[ticker:CMRX]]) announced over the weekend that it would close the trials after reporting detailed results of the failed Phase 3 trial during the tandem meetings of the Center for International Blood & Marrow Transplant Research and the American Society for Blood and Marrow Transplantation. The company now plans to reassess the drug in new Phase 2 studies of its pill, known as brincidofovir, and meet with the FDA to determine the next steps.
When Chimerix initially announced in December that the brincidofovir had failed, the company said that in the 24 weeks following a stem cell transplant, the drug reduced infections from cytomegalovirus (CMV), a virus that can take advantage of patients with compromised immune systems. But those infections returned. Once off of the Chimerix drug, patients showed a higher rate of CMV infection in the weeks afterward compared to the group that received a placebo, the company reported.
Chimerix said over the weekend that the drug’s failure appears to be associated with higher use of corticosteroids and other immune system-suppressing therapies to treat graft versus host disease, a sometimes fatal complication that can develop when newly transplanted donor cells attack the body of a transplant recipient. Chimerix said that use of immune-suppressing drugs to prevent graft versus host disease is known to increase the risk of infections, including CMV infections, after a patient stops taking antiviral drugs.
One sign of graft versus host disease is diarrhea, which is also a known side effect of the Chimerix drug. In an earlier study, Chimerix developed a safety plan to monitor and manage diarrhea by temporarily stopping treatment with the drug when it occurred. The problem continued to occur in Chimerix’s Phase 3 trial, as patients on its drug had more frequent diarrhea than those on placebo.
[The following four paragraphs were added to include details from the conference call.] On a Monday morning conference call to explain the clinical trial results, CEO Michelle Berrey said that at some of the clinical trial sites, the diarrhea was presumed to be graft versus host disease and was treated with corticosteroids, rather
