Lexicon Releases data for Rheumatoid Arthritis study

THE WOODLANDS, Texas - Lexicon Pharmaceuticals, Inc. (Nasdaq: LXRX) has released top-line results from a recently completed Phase 2a study of LX2931 in patients with rheumatoid arthritis (RA). LX2931 is an orally-delivered, small molecule drug candidate that inhibits sphingosine-1-phosphate (S1P) lyase, an enzyme important for modulating the immune system by controlling S1P levels in lymphoid tissues. The trial was the first test of this new anti-inflammatory mechanism of action in patients and was designed to obtain safety and tolerability information and signals of efficacy.

Results from the 12-week, randomized, double-blind, placebo-controlled study in 208 patients with RA demonstrated that all three doses tested, 70 mg, 110 mg, and 150 mg given once per day, were well tolerated over the 12-week treatment period. Taken together, the data also suggested that patients treated with 150 mg once daily of LX2931 showed an improvement in the primary efficacy endpoint, the percentage of patients achieving an American College of Rheumatology 20 (ACR20) response at week 12 (60% versus 49% for placebo). Patients treated with 70 mg or 110 mg once daily did not indicate improvement in the ACR20 at week 12 (44% and 41% response rates, respectively) relative to placebo. Adverse events for all three LX2931 dose groups were predominantly mild-to-moderate, with frequencies similar to the placebo group.

"We believe the preliminary signal of efficacy and the favorable safety profile observed in this trial supports further study of additional higher doses of LX2931 as an orally-delivered treatment for rheumatoid arthritis," said Dr. Arthur T. Sands, President and CEO of Lexicon. "While we were disappointed by the unusually high placebo effect in this trial, we are encouraged by the excellent overall safety profile observed in the first test of this new mechanism of action in patients with RA."

The company intends to begin discussions with potential pharmaceutical partners to pursue further development of LX2931 in rheumatoid arthritis.