Jeffrey A. Sosman, MD, professor of medicine, Director, Melanoma and Tumor Immunotherapy Program, Vanderbilt University School of Medicine, Vanderbilt-Ingram Cancer Center, describes the mechanism of action of ipilimumab in patients with melanoma.

 Sosman says ipilimumab works by binding to the “brakes” of a T cell, which prohibits the T cell from turning off its immune response. Recent data also suggests that ipilumamab may play a role in eliminating one of the subsets of cells that are immune suppressive, Sosman says, suggesting that ipilumamab may have a more complicated role in melanoma treatment than researchers previously thought.

The unregulated activation of the T cells is what causes both the response and some of the toxicity, Sosman says.

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Dr. Sosman on the Mechanism of Action of Ipilimumab

Jeffrey A. Sosman, MD, Professor of Medicine, Director, Melanoma and Tumor Immunotherpay Program, Vanderbilt University School of Medicine, Vanderbilt-Ingram Cancer Center, discusses how immunotherapies work in patients with melanoma or renal cancer.

Sosman says that though response rates to interferon and interleukin 2 are low, these responses are long-lasting. In this scenario, Sosman believes, the patient’s immune response is gaining memory.

Patients with renal cancer that have been treated with interleukin 2 and have gone into a complete remission are less likely to relapse compared with a patient who has been free of disease after a nephrectomy, Sosman says.

The best example of the change in immune response memory, Sosman says, is seen in patients with melanoma who develop vitiligo after responding to treatment. Those responses remain consistent, suggesting that the memory has been induced.

Jeffrey A. Sosman, MD

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Dr. Sosman on the Mechanism of Action of Ipilimumab

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