Array BioPharma (ARRY) announced late Thursday that its rheumatoid arthritis drug candidate ARRY-162 was no more effective than a placebo in a mid-stage study. The disappointing results caused the developer's shares to drop nearly 30 percent in premarket trading on Friday.
The 12-week study involved 201 patients with RA that had an inadequate response to the standard treatment, methotrexate. Preliminary analysis of the trial data showed that none of the three groups treated with Array's drug candidate achieved a statistically significant response rate compared with the placebo group.
According to Array's statement, the study's placebo response rates were higher than expected for this patient population and showed regional differences. Trial data showed that patients in South America had substantially higher placebo response rates than those in Eastern Europe. "While we are disappointed in the overall efficacy outcome, we were pleased with the confirmation of the favorable safety profile and are continuing to evaluate the regional results," said Kevin Koch, president and chief scientific officer. Complete results of the study will be presented at a medical conference next year.