Shares of Chimerix plunged 40 percent Monday after the Durham drug maker announced that its experimental anti-viral, brincidofovir, failed to prevent viral infections in high-risk patients.
The company’s shares closed at a new all-time low of $4.55 Monday after the company said it was halting two other clinical trials based on the disappointing drug trial results. Chimerix stock had climbed as high as $57.43 in August before the company was beset by complications with its once-promising anti-viral.
The latest setback comes two months after Chimerix reported that patients taking brincidofovir in the clinical trial died at higher rates than those taking a placebo. The drug did not cause the deaths, but it also did not help the patients.
In its most recent announcement, Chimerix said on Saturday that brincidofovir did not prevent infection of cytomegalovirus in the 24th week of treatment of patients with bone-marrow transplants. The announcement was made in Honolulu, Hawaii, at the combined annual meetings of the Center for International Blood and marrow Transplant Research and the American Society of Blood and Marrow Transplantation.
The clinical trial, called Suppress, involved 452 cell transplant patients at high risk for cytomegalovirus, a common virus that’s harmless to healthy people but potentially lethal to people with compromised immune systems.
Chimerix, which employed 130 people in December, said brincidofovir worked through the first 14 weeks of treatment, but then lost effectiveness. The company said the failure appears to be connected to the use of corticosteroids and other immune suppressing therapies for the prevention of graft versus host disease, a condition in which the transplanted cells attack the patient’s cells and organs.
No longer viable
Brincidofovir was touted as a treatment that could destroy fatal viruses, including potentially Ebola disease, without the crippling side-effects of current treatments.
Chimerix said that even though brincidofovir did not deliver on its promise in the Suppress trial, neither did it produce the dreaded side effects, which would typically include bone marrow toxicity and kidney toxicity.
In December, Chimerix halted patient enrollment in its Surpass and Sustain clinical trials for the prevention of cytomegalovirus in kidney transplant patients until it could assess the failed Suppress clinical trail. As a result of this weekend’s developments, Chimerix said it closed both the Surpass and Sustain clinical trials, but plans to continue other research.
In research note, William Blair analyst Y. Katherine Xu said the oral formulation of brincidofovir is not longer viable for preventing viral infections.
Chimerix is assessing its next steps with brincidofovir, including developing an an intravenous formulation. The company said the antiviral is protected by patents until 2034.