Array BioPharma Inc. announced that it received a $3 million payment from AstraZeneca for achieving a phase 2 milestone for AZD6244 (ARRY-142886). The payment was triggered upon dosing the first patient in a phase 2 trial. AZD6244 (ARRY-142886) is a selective MEK inhibitor that was in-licensed by AstraZeneca from Array in December 2003.

The previously announced Phase 2 randomized study will compare AZD6244 (ARRY-142886) to temozolomide in the treatment of stage III/IV melanoma patients. AstraZeneca expects to enrol up to 180 patients at approximately 40 centres worldwide. Additional Phase 2 studies, in a range of other tumours, are scheduled to start this year.

Initiation of the Phase 2 study is based on the results of the Phase 1b study which recently completed recruitment, and which included patients with melanoma and a variety of other solid tumours. The Phase 1 study clearly demonstrated that AZD6244 (ARRY-142886) inhibits MEK and associated downstream markers in tumours at doses deemed well tolerated. The full results of this study will be published later in the year.

Array was responsible for filing the IND and conducting the Phase 1 clinical testing of AZD6244 (ARRY-142886). AstraZeneca is responsible for all other aspects of clinical development and commercialization.

AstraZeneca acquired exclusive worldwide rights to AZD6244 and certain second-generation compounds for all oncology indications in December 2003. Array retains the rights to all therapeutic indications outside of oncology for compounds not selected by AstraZeneca as part of the collaboration.

AZD6244 (ARRY-142886) is a potent, selective MEK inhibitor that is orally active, that blocks signal transduction pathways implicated in cancer cell proliferation and survival. AZD6244 (ARRY-142886) has shown tumour suppressive activity in multiple pre-clinical models of human cancer including melanoma, pancreatic, colon, lung, and breast cancers.

MEK is a critical enzyme at the intersection of several biological pathways, which regulates cell proliferation and survival as part of the Ras/Raf/MEK/ERK pathway. Activation of the Ras/Raf/MEK/ERK pathway has been implicated in many cancers, including lung, pancreatic, colon, melanoma and thyroid cancer. MEK inhibition is an attractive anti-cancer strategy as it has the potential to block inappropriate signal transduction regardless of the upstream position of the oncogenic aberration.