Isis Ends Program, Still Has Options For Rheumatoid Arthritis Drug

Xconomy San Diego — 

Wall Street showed little reaction today after Carlsbad, CA-based Isis Pharmaceuticals (NASDAQ: ISIS) said it would halt development of its antisense drug ISIS-CRPRx for treating rheumatoid arthritis. Isis shares lost 58 cents, or slightly less than 2 percent, in regular trading today, closing at $28.65 a share.

Isis said data from a mid-stage trial of the same drug for treating atrial fibrillation (an irregular heartbeat) is expected in the first half of 2014, and Isis would continue to test the drug in other diseases.

In a statement today, Isis reported results of a mid-stage clinical trial of 51 rheumatoid arthritis patients who had chronically elevated levels of C-reactive protein (CRP), which is strongly associated with numerous inflammatory and cardiovascular diseases. Isis said its treatment reduced CRP levels by as much as 67 percent, but the overall improvements in rheumatoid arthritis symptoms were not statistically significant in comparison to a placebo group.

The company statement quotes Richard Geary, an Isis senior vice president of development, as saying, “We are pleased with the consistency of CRP lowering across all of our clinical studies, but we are disappointed that we did not see a greater impact on RA [rheumatoid arthritis] symptoms in these patients.”

Isis said study patients who were treated with the Isis drug “achieved substantial, dose-dependent reductions in CRP early in treatment [and] that were prolonged through the treatment process,” as well as improvements in the symptoms of rheumatoid arthritis. The improvements correlated with reductions in CRP, but were not sufficiently greater than improvements observed in the placebo groups to justify further development of the drug for rheumatoid arthritis, Isis said.

The treatment uses Isis’s proprietary “antisense” technology, which is intended to prevent a mutated gene from producing disease-causing proteins by binding to messenger RNA molecules during protein synthesis.