Phase 1 clinical data: ARRY-520 shows positive preliminary results in treating multiple myeloma

Array BioPharma Inc. (NASDAQ: ARRY) today announced the presentation of positive Phase 1 clinical data for its novel kinesin spindle protein (KSP) inhibitor, ARRY-520. The data, which were presented at the 2010 Annual Meeting of the American Society of Hematology (ASH) in Orlando, Florida, indicate that ARRY-520 was well tolerated and has shown encouraging preliminary results in the treatment of multiple myeloma. ARRY-520 is a novel, first-in-class, highly potent, selective KSP inhibitor currently being investigated in a single-agent Phase 2 clinical trial and a Phase 1b combination trial with bortezomib plus dexamethasone in patients with relapsed and refractory multiple myeloma. The poster is available as a PDF on Array's website at www.arraybiopharma.com.

“Given the compelling preclinical activity in combination with proteasome inhibitors, we are enthusiastic about its potential both as a single agent and in combination therapy.”

"ARRY-520 has shown promising preliminary single agent activity in patients with relapsed and refractory multiple myeloma," said Robert Orlowski, M.D., Ph.D., of The University of Texas MD Anderson Cancer Center. "Given the compelling preclinical activity in combination with proteasome inhibitors, we are enthusiastic about its potential both as a single agent and in combination therapy."

A Phase 1/2 Trial of the KSP Inhibitor ARRY-520 in Relapsed/Refractory Multiple Myeloma
(Publication #1959) - Saturday, December 4, 2010, 5:30 - 7:30 p.m. E.T., Orange County Convention Center, Hall A3/A4, Poster Board no.: I-939

This Phase 1, open-label, multicenter, dose-escalation study was designed to evaluate the safety, pharmacokinetics and pharmacodynamics of ARRY-520 administered intravenously (IV) on Day 1 and Day 2 repeated every 14 days in patients with multiple myeloma. This study enrolled 30 evaluable patients with relapsed or refractory multiple myeloma with at least two prior lines of therapy (including both a bortezomib and an IMiD-based regimen) with a median of five prior therapies. The maximum tolerated dose (MTD) of ARRY-520 was 1.25 mg/m²/day without the use of hematopoietic growth factors. With the addition of prophylactic granulocyte-colony stimulating factor (G-CSF), the MTD of ARRY-520 was 1.50 mg/m²/day. Neutropenia has been the most commonly reported adverse event and mucositis became prevalent at higher dose levels.

ARRY-520 has shown promising preliminary clinical activity as a single agent in this heavily pretreated patient population. Of 30 evaluable patients, confirmed partial responses have been observed in two patients, one of which had eight prior lines of treatment and has been on study for more than 18 months. In addition, confirmed minimal responses have been reported in two patients. Twelve patients remain on study to date, including all responders, and eight patients have been treated for longer than six months. The Phase 2 portion of this study is underway.