The drug, R788, is currently being evaluated in immune thrombocytopenic purpura (ITP), rheumatoid arthritis (RA) and lymphoma patients.
Rigel said that based on these initial results, it has submitted an amended protocol to the FDA to expand this trial to allow for a greater range of dose regimens and to continue to treat those patients that are responding beyond 90 days. The company expects to receive final results from the study by the end of 2007.
Rigel Pharmaceuticals also reported that patients had begun enrollment in another phase II trial to evaluate the safety and efficacy of R788 for the treatment of B-cell lymphoma. Approximately 80% of patients with non-Hodgkin's lymphoma have the B-cell variety. Research has shown that R788 effectively interrupts the growth of B-cells and signaling proteins that contribute to the survival of these tumors.
The primary efficacy endpoint will be overall response rate according to standard criteria. Secondary efficacy, safety and pharmacodynamic endpoints, as well as the role of syk activation in predicting responses, will also be measured. Depending on enrollment, results of the clinical trial are expected in 2008.