BOULDER, Colorado—Array BioPharma Inc announced that Phase 1b data from a 3-arm study of 28 rheumatoid arthritis (RA) patients ARRY-797 showed inhibition of C-reactive protein (CRP) levels during the first 3 weeks of dosing and a beneficial reduction in bone remodeling markers throughout treatment. There was also a trend toward lower pain scores over the 28-day course of the study. Nonetheless, the company is stopping development of ARRY-797 for RA and other chronic inflammatory diseases.

"In the 28-day RA study, ARRY-797 demonstrated a transient inhibition of the inflammatory biomarker CRP and a trend towards analgesic efficacy in the pain endpoint," said Kevin Koch, PhD, President and Chief Scientific Officer. "Since these results are similar to other p38 inhibitors evaluated in rheumatoid arthritis, these findings have led us to discontinue testing of ARRY-797 in chronic inflammatory diseases. We continue to believe that a p38 inhibitor holds promise in treating patients with cancer and sub-chronic pain."

Array has also stopped enrollment of new patients into a clinical trial of ARRY-797 in ankylosing spondylitis patients.

ARRY-797 is a potent and highly selective p38α inhibitor that decreases production of PGE2 as well as cytokines such as TNF and IL-1. p38 is a kinase target that regulates the production TNF, IL-1, and IL-6 as well as PGE2. PGE2 is an important mediator of inflammatory pain and its production is the target of NSAIDs. Many forms of acute and chronic pain have inflammatory origins, and pan-cytokine suppression may treat both the inflammation and the resulting pain. Array believes modulation of all three cytokines plus PGE2 may be more effective than inhibition of any one in isolation for controlling both the underlying inflammation and the resulting symptoms such as pain.