Pfizer Anti-CTLA4 antibody trial for melanoma stopped for futility

Implications: The Data Safety Monitoring Board halted the Phase III randomized open label trial comparing the Pfizer anti-CTLA4 antibody, tremelimumab, to "standard" (and generally ineffective) chemotherapy for metastatic melanoma. The Board has reported that there is no statistical difference between the primary endpoint, overall survival, between the two study arms. Further, statistical analysis reportedly shows that further examination is "futile" or basically unlikely to ever show a statistical difference. This is a major setback for the hopes of many investigators and patients who felt that the anti-CTLA4 antibodies represent an encouraging potential new therapy for metastatic melanoma, a disease for which there is no universally accepted or generally effective therapy.

Analysis: Two questions that come from these results:

Will this completely halt all efforts by Pfizer to develop this drug in melanoma?

Will these results effect the parallel efforts of BMS and Medarex to develop a similar (but not identical) drug for the same indications?