Positive interim results of ARRY-380 in Phase 1 trial announced

Array BioPharma Inc. (NASDAQ: ARRY) today announced positive interim results of its novel, small molecule HER2 (ErbB2) inhibitor, ARRY-380, in a Phase 1 trial in advanced cancer patients. These results are being presented at the 2009 San Antonio Breast Cancer Symposium (SABCS). The complete poster (#5111) entitled, “A Phase 1 Study to Assess the Safety, Tolerability and Pharmacokinetics of ARRY-380 - an Oral Inhibitor of ErbB2,” is available as a PDF on Array's website at www.arraybiopharma.com.

Interim results showed that ARRY-380 at doses greater than or equal to 200 mg BID demonstrated evidence of tumor regression in eight out of ten heavily pre-treated patients with HER2 expressing cancers. Of these eight patients, four had prolonged stable disease for 16 weeks or longer. ARRY-380 has been well-tolerated; the predominant adverse events have been Grade 1 and included nausea, rash and fatigue; only minimal diarrhea has been reported. In completed cohorts, no Grade 3 or 4 treatment-related adverse events and no cardiac adverse events have been observed. The maximum tolerated dose of ARRY-380 in this Phase 1 trial has not yet been achieved, and dose escalation is ongoing.

“I am optimistic about this orally available, selective HER2 inhibitor, ARRY-380; to date, it has been well-tolerated and has shown activity in patients previously treated with trastuzumab and lapatinib,” said Stacy Moulder, M.D., Clinical Investigator, M.D. Anderson Cancer Center. “If further clinical testing continues to show positive results, ARRY-380 could provide HER2+ cancer patients a promising new therapy option.”

“Maintaining tumor remission while improving breast cancer patients’ quality of life represents one of the largest commercial opportunities in cancer therapy,” said Kevin Koch, Ph.D., President and Chief Scientific Officer. “In this clinical trial, ARRY-380 has been well-tolerated and demonstrated tumor regressions as a monotherapy in several HER2+ tumor types. In preclinical studies, ARRY-380 was superior in reducing tumor size when compared to selective HER2 inhibitors, such as trastuzumab, and was active when combined with other standard-of-care therapies.”

In addition to the clinical results, preclinical data on ARRY-380 were presented at the SABCS: Poster # 5104 “In Vivo Activity of ARRY-380, a Potent, Small Molecule Inhibitor of ErbB2 in Combination with Trastuzumab, Docetaxel or Bevacizumab.” This poster will also be available as a PDF on Array’s website.