In previous years shares in biotech and pharmaceutical companies have routinely jumped on the release of positive research results at the American Society of Clinical Oncology annual meeting. Now that the curtain has closed on the 2010 event, held in Chicago June 4-8, it is clear (see table below) that the “ASCO-effect” was operating in reverse this year.

The volatile capital markets had a great deal of influence on the share prices of biotech companies this time around, plus many of the companies listed saw their share values move higher in the run up to the meeting. During the event, trading volumes for these companies was at least four to five times normal and, as a result, prices adjusted to post-ASCO selling.

Bristol-Myers Squibb and Celgene’s presentations stood out among the dizzying array of data offered. Bristol-Myers Squibb reported on a study of its experimental drug ipilimumab, a monoclonal antibody against cytotoxic T-lymphocyte antigen 4 (CTLA-4), which showed that the drug was effective at bolstering the immune system of patients with advanced melanoma. On average the trial improved life spans of these patients by about four months. The company plans to file a marketing application with the U.S. Food and Drug Administration later this year. Some analysts have estimated it could have peak annual sales of up to $1 billion.

Physicians gave positive feedback on Celgene’s study results showing its drug Revlimid may have a role as a maintenance drug and as a lymphoma treatment. Early data showed a Revlimid regimen in front-line follicular lymphoma had a 93 percent overall response rate among 30 patients. The drug also showed positive results as a post-transplant drug in myeloma patients. Treatment with a maintenance regimen of Revlimid resulted in a 58 percent reduction in the risk of tumor progression compared to placebo.

The median time to progression in the placebo arm was 25.5 months, while median time to progression in the Revlimid arm has not yet been reached. In a separate but similar study also looking at Revlimid maintenance in multiple myeloma patients, Revlimid treatment resulted in a 54 percent reduction in the risk of tumor progression compared to placebo. Revlimid is approved as a treatment for multiple myeloma in patients who have been treated with at least one other therapy.