Genetic markers implicated in fatal side effects of schizophrenia drug

Dec 20 2004

Genaissance Pharmaceuticals today announced results from its CARING (Clozapine and Agranulocytosis Relationships Investigated by Genetics) study, reporting the discovery of genetic markers that the Company believes predict who is at risk of developing clozapine-induced agranulocytosis, a life-threatening decrease of white blood cells that requires frequent blood testing of patients.

The Company said the findings may apply to other drugs that also affect white blood cell counts.

"In light of recent drug withdrawals and labeling restrictions due to rare but serious adverse drug events, these results underscore the potential of pharmacogenetics to identify individuals who are at particular risk for developing fatal adverse drug reactions," said Kevin Rakin, President and Chief Executive Officer of Genaissance. "The CARING study is a powerful, cost-effective model for understanding the contribution of genetics to other adverse drug reactions and provides strong evidence of the power of Genaissance's proprietary platform. We believe an appreciable market exists for a genetic diagnostic test for predicting which patients are at-risk for developing agranulocytosis in response to clozapine and other drugs."

"Our analyses indicate that genetic variation appears to explain a significant portion of the risk of developing clozapine-induced agranulocytosis," added Carol R. Reed, M.D., Vice President of Medical Affairs of Genaissance. "We believe the sensitivity and selectivity of these markers could support further development of a diagnostic test. Additionally, one of the associations we identified in the HLA (Human Leukocyte Antigen) complex has been previously reported to be associated with clozapine-induced agranulocytosis. Our results confirm this finding, building confidence that our novel findings will be validated in future studies."

"Clozapine has long been accepted as one of the most effective medications for treating schizophrenia but has had limited utilization due to the risk of inducing agranulocytosis," said John Kane, M.D., Chairman of the Department of Psychiatry at The Zucker Hillside Hospital, Professor of Psychiatry at Albert Einstein College of Medicine, and co-Chair of the CARING Steering Committee. "These findings have moved us one step closer to realizing an alternative approach in the prescribing of clozapine where a one-time genetic test may someday alleviate the need for continuous blood monitoring for the majority of clozapine treated patients."

Genaissance believes that these scientific findings have uncovered new clues to the underlying biological and physiologic mechanisms of drug-induced agranulocytosis and provide a starting point for elucidating a common mechanism across drugs from different classes that carry this rare but devastating side effect.

Genaissance is preparing a patent application designed to protect its novel findings and will provide further details after its anticipated filing of this application with the United States Patent and Trademark Office.

http://www.genaissance.com/