Array BioPharma Inc. (NASDAQ: ARRY) today announced top-line results from its Phase 1 seven-day dose escalation trial up to 1,200 mg daily of p38 inhibitor, ARRY-797, in healthy volunteers. In addition, the top-line results were announced in a second study, where ARRY-797 was evaluated in a 28-day Phase 1b trial in stable rheumatoid arthritis (RA) patients taking methotrexate. This study compared two doses of ARRY-797 to placebo.

A preliminary analysis of both trials indicates that ARRY-797 was well tolerated with a pharmacokinetic profile consistent with earlier studies. In the 28-day, three-arm RA study with a total of 28 patients, ARRY-797 showed inhibition of CRP levels (marker of inflammation) only during the first three weeks of dosing and a beneficial reduction in NTx levels (marker of bone remodeling) throughout the study. In addition, ARRY-797 showed a trend to improve the patients’ assessment of pain (VAS score) over the course of the study.

“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, Ph.D., 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.”

The Company continues to conduct a full analysis of safety, pharmacokinetics and efficacy data from both studies. Array anticipates that complete results from the studies will be presented at a medical conference in 2010. Based on these preliminary results, Array plans to cease the enrollment of new patients in its current clinical trial of ARRY-797 in ankylosing spondylitis patients.

Phase 1b Dose Escalation Trial in Healthy Volunteers: Clinical Study Design and Results

This Phase 1b dose escalation trial was a randomized, double-blind, placebo-controlled study in healthy volunteers and was designed to evaluate the safety and pharmacokinetics of ARRY-797 after single-day and multiple-day administration of ARRY-797. Single ascending-doses of 900 mg (once) and 1,200 mg/day (800 mg followed by 400 mg 12 hours later), and multiple-day, ascending-doses of 200, 300 and 400 mg/day TID (every eight hours) for eight consecutive days were explored.

Safety, Tolerability and Pharmacokinetics: Overall, ARRY-797 was well-tolerated after single-day and multiple-day administration of total daily doses of 600 mg, 900 mg, and 1,200 mg. In the multiple-day cohorts up to 400 mg TID, no adverse event (AE) was reported by more than one subject in any treatment group and all AEs were considered mild in intensity. In the single-day cohorts, mild dizziness was reported by two of the 6 subjects receiving a 900 mg dose of ARRY-797 and moderate dizziness by one of the 6 subjects receiving 800 mg followed by 400 mg ARRY-797. Approximately dose-proportional increases in mean total and peak exposures were observed with increasing dose following single- and multiple-dose administration. Mean plasma concentrations of ARRY-797 reached steady-state on day two after repeat-dose administration with modest accumulation.

Phase 1b 28-day Study in Patients with RA: Clinical Study Design and Results

This Phase 1b trial was a randomized, double-blind, placebo-controlled design that enrolled 29 patients with RA. Twenty eight patients completed four weeks of treatment. The trial was conducted at six sites in the United States. Patients received either 100 mg or 200 mg ARRY-797 twice daily, or placebo.