Array BioPharma Inc. (NASDAQ ARRY) announced topline results from its Phase 1 sevenday dose escalation trial up to 1,200 mg daily of p38 inhibitor, ARRY797, in healthy volunteers. In addition, the topline results were announced in a second study, where ARRY797 was evaluated in a 28day Phase 1b trial in stable rheumatoid arthritis (RA) patients taking methotrexate. This study compared two doses of ARRY797 to placebo.

A preliminary analysis of both trials indicates that ARRY797 was well tolerated with a pharmacokinetic profile consistent with earlier studies. In the 28day, threearm RA study with a total of 28 patients, ARRY797 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, ARRY797 showed a trend to improve the patients assessment of pain (VAS score) over the course of the study.

“In the 28day RA study, ARRY797 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 ARRY797 in chronic inflammatory diseases. We continue to believe that a p38 inhibitor holds promise in treating patients with cancer and subchronic 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 ARRY797 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, doubleblind, placebocontrolled study in healthy volunteers and was designed to evaluate the safety and pharmacokinetics of ARRY797 after singleday and multipleday administration of ARRY797. Single ascendingdoses of 900 mg (once) and 1,200 mg/day (800 mg followed by 400 mg 12 hours later), and multipleday, ascendingdoses of 200, 300 and 400 mg/day TID (every eight hours) for eight consecutive days were explored.

Safety, Tolerability and Pharmacokinetics Overall, ARRY797 was welltolerated after singleday and multipleday administration of total daily doses of 600 mg, 900 mg, and 1,200 mg. In the multipleday 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 singleday cohorts, mild dizziness was reported by two of the 6 subjects receiving a 900 mg dose of ARRY797 and moderate dizziness by one of the 6 subjects receiving 800 mg followed by 400 mg ARRY797. Approximately doseproportional increases in mean total and peak exposures were observed with increasing dose following single and multipledose administration. Mean plasma concentrations of ARRY797 reached steadystate on day two after repeatdose administration with modest accumulation.

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

This Phase 1b trial was a randomized, doubleblind, placebocontrolled 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 ARRY797 twice daily, or placebo. In addition, all patients were on a background of methotrexate and could receive certain NSAIDs (including COX2 inhibitors), corticosteroids (lowdose), opioids/analgesics, aspirin, or acetaminophen. Patients were evaluated every seven days for improvement in clinical signs and symptoms according three measures CRP levels (marker of inflammation), patients assessment of arthritis pain (VAS score), and NTx levels (marker of bone remodeling).

Effects on Signs and Symptoms of Rheumatoid Arthritis The CRP levels at the 200 mg BID dose of ARRY797 showed a statistically significant decrease during the first three weeks of the study but returned to baseline on week four. Also, the patients assessment of pain (VAS score) showed trends to decrease in the 200 mg BID arm. The NTx levels for both active arms separated from placebo by as much as 30 percent in the 100 mg arm and 50 percent in the 200 mg arm.

Safety, Tolerability and Pharmacokinetics ARRY797 was welltolerated through 29 days of dosing. There were no premature discontinuations for serious AEs in any of the study arms. The most common AEs were generally mild or moderate and were not significantly different than placebo. Based upon a preliminary assessment, the exposure of ARRY797 was consistent with previous studies in healthy volunteers, there were no apparent drugdrug interactions between methotrexate and ARRY797, and no apparent food effect was observed.

ARRY797 in Acute Pain

The efficacy of ARRY797 previously was evaluated in two acute inflammatory pain trials in patients with postsurgical dental pain. ARRY797 achieved its primary and secondary endpoints for analgesic efficacy and was welltolerated in both trials.

In the first trial, the analgesic effect of 400 mg of ARRY797, compared to placebo, was statistically significant based upon the primary endpoint of total pain relief over six hours post dose (p