Rigel initiates two Phase IIb rheumatoid arthritis trials

The first new Phase IIb clinical trial (Taski 2) will evaluate RA patients receiving 100mg of R788 PO bid (orally, twice daily) or 150mg PO qd (orally, once daily), compared with those receiving placebo in a multi-center, randomized, double blind, placebo controlled, parallel dose study of R788 in patients who have failed to respond to methotrexate. The company expects to enroll approximately 420 patients in this clinical trial each of whom will continue to receive a stable dose of methotrexate throughout the course of the six month clinical trial.

The second Phase IIb clinical trial (Taski 3) will evaluate a group of RA patients receiving 100mg of R788 PO bid compared with a group receiving placebo in a multi-center, randomized, double blind, placebo controlled, parallel dose study of R788 in patients who have failed at least one marketed biologic agent. The class of biologic agents generally includes anti-TNF injectables commonly used to treat RA, but could include other therapies as well.

The company expects to enroll approximately 195 patients in the Taski 3 clinical trial, each of whom will receive R788 or placebo over a three month treatment period. During this clinical trial, enrolled patients may continue on their stable dose of methotrexate or other (non-biologic) therapies.

The primary objectives for both Taski 2 and Taski 3 are to measure the efficacy of R788 as determined by ACR20 (American College of Rheumatology responder rates showing a minimum of 20% improvement in RA symptoms and pain) scores at six months and three months, respectively.

The two clinical trials will be conducted concurrently at a number of clinical research centers throughout the US, Latin America, and Europe in order to evaluate the efficacy of R788 compared to placebo in distinct rheumatoid arthritis (RA) patient groups. Results of the clinical trials are expected to be available in late 2009.