Dr. Ribas on the Efficacy of Ipilimumab in Melanoma

Antoni Ribas, MD, PhD, the director of the Tumor Immunology Program Area at UCLA's Jonsson Comprehensive Cancer Center, discusses the efficacy of ipilimumab for the treatment of melanoma.

Ipilimumab blocks CTLA-4, which is a negative regulator of the immune system, and is important in the activation step of the immune system.

When the immense system is being activated, CTLA-4 has its brake effect. If the brake effect is released, Ribas says, immune system cells may be able to target the cancer, while others may target other tissues, creating some risk.

PD-1 is at the defector stage of the immune system, Ribas says, and releasing PD-1 is more likely to achieve a rapid response and be more targeted to the T cells that are cancer-specific.