Acorda Therapeutics Inc. announced that it has increased the frequency of blood cell count monitoring for participants to weekly in its Phase 3 program of tozadenant for Parkinson’s disease. The company took this action in response to cases of agranulocytosis, possibly drug-related, and in some cases associated with sepsis and death. Agranulocytosis is the absence of white blood cells, which fight infection.
The news caused Acorda's shares to plummet about 38 percent. The company also paused new enrollment in the long-term safety studies, pending further discussion with the independent Data Safety Monitoring Board (DSMB) and the U.S. Food and Drug Administration (FDA).
The Phase 3 program includes an ongoing pivotal efficacy and safety study (CL05) and two long-term safety studies (CL05 extension and CL06). Including the previously conducted Phase 2b study, approximately 890 patients have been exposed to tozadenant and 234 have been exposed to placebo. This corresponds to approximately 300 patient years of tozadenant exposure and 75 patient-years of placebo. There have been seven cases of sepsis, all in the tozadenant groups, five of which were fatal, the company said. Four of the sepsis cases were associated with agranulocytosis, two had no white blood cell counts available at the time of the event, and one had a high white blood cell count.
“We have taken these steps in the best interests of the safety of patients in the tozadenant studies, which is our top priority,” said Ron Cohen, M.D., Acorda's president and CEO. “Contingent on further input from the DSMB and FDA, we continue to expect to report efficacy and safety results of the double-blind Phase 3 study in the first quarter of 2018.”