Bristol-Myers' immunotherapy drug nivolumab takes center stage at ASCO

CHICAGO--Bristol-Myers Squibb ($BMY) arrived at ASCO with one of the most closely watched experimental immunotherapy drugs in the pipeline. And racing against some major league rivals, the biopharma company will leave with its frontrunner reputation for nivolumab intact.

Nivolumab's claim to fame as a breakthrough melanoma therapy was enhanced by long-term results from their Phase I study, which show that the PD-1 drug demonstrated durable responses among a significant group of patients with Stage 4 melanoma. Close to a third of the patients in the study experienced tumor shrinkage, compared to a historical trend rate of 5% to 10% for Yervoy, Bristol-Myers' pioneering immunotherapy for this disease.

Researcher Mario Sznol spelled out the data on Saturday, highlighting the 33 of 107 patients whose tumors shrank at least 30%. There was a rapid response among 45% of the patients and the median duration of response was two years, says Sznol. The median overall survival for patients was 16.8 months, with the optimal dose being used in subsequent studies hitting an impressive OS rate of 20.3 months. (Yervoy manages about half of that rate.) There was no comparison arm in the Phase I study, but Sznol noted that OS rates clearly exceeded anything seen in newly approved melanoma therapies.

The researcher was also clearly pumped about the safety profile of nivolumab, noting that "this is one of the best tolerated drugs I've seen in the clinic. We're really in an era of remarkable advances in melanoma."

Bristol-Myers has some competition to consider. Merck ($MRK) has a competing PD-1 drug--lambrolizumab--in the clinic and Roche ($RHHBY) has its PDL-1 drug to boast about. The biological pathway here is simple to understand. Targeting the PD-1 receptor unleashes a T-cell attack on cancer cells, essentially deactivating a cloaking mechanism that has prevented an immune response. Just days ago Bristol-Myers Squibb outlined even better response rates with a combination of Yervoy and nivolumab, a potential megablockbuster combination approach that could earn billions of dollars a year.

Bristol-Myers isn't wasting any time in exploring the full potential for this therapy. It has 6 late-stage studies under way for nivolumab, with fast-track status in place for melanoma, lung cancer and kidney cancer. If the data continues to come in to support these early results, Bristol-Myers will have a major new therapy to rely on. 

The data underscore a few key points on the cancer drug development front. Positive early-stage proof-of-concept data is enough to rev up the clinical development plan, with developers shifting straight into late-stage work, potentially cutting years out of the development process. Improving understanding of the biology of cancer and fresh insights on immunotherapy are revolutionizing treatment options for patients. And the FDA is eager to help out when Big Biopharma comes calling.

Special Report: Top 10 experimental cancer drugs - 2013