Antoni Ribas, MD, PhD

Videos

Antoni Ribas, MD, PhD, professor of Hematology and Oncology and director of the Tumor Immunology Program Area at UCLA Jonsson Comprehensive Cancer Center, discusses how to appropriately sequence therapies for patients with melanoma.

Sequencing Agents for the Treatment of Patients With Melanoma

Antoni Ribas, MD, PhD, professor of medicine, Jonsson Comprehensive Cancer Center, University of California, Los Angeles, discusses the excitement surrounding immunotherapies for the treatment of patients with melanoma.

By taking away the PD-1/PD-L1 break, which is relevant inside the tumor, it is possible to study a tumor and determine if the PD-1/PD-L1 regulatory pathway was turning off T cells

PD-1/PD-L1 inhibitors are easier to study than older immunotherapies that require turning on the immune system

Researchers are able to determine who will respond to PD-1/PD-L1 inhibitors and how to intervene in those patients that will not

The Excitement Surrounding Immunotherapies for Melanoma

Antoni Ribas, MD, PhD, professor of medicine, Jonsson Comprehensive Cancer Center, University of California, Los Angeles, discusses the outlook for BRAF inhibitors in melanoma.

Read more about BRAF inhibitors for the treatment of melanoma and

Articles

The Outlook for BRAF Inhibitors in Melanoma

Antoni Ribas, MD, PhD, professor of medicine, Jonsson Comprehensive Cancer Center, University of California, Los Angeles, discusses the development process of PD-1 antibody MK-3475 in melanoma.

Physicians are eagerly awaiting data from a phase II clinical trial comparing chemotherapy to MK-3475 in patients who have previously received ipilimumab

A trial studying two dosing regimens of MK-3475 compared to ipilimumab in frontline therapy for patients with metastatic melanoma is currently accruing

MK-3475 is also being developed in other cancers, such as lung, bladder, and head and neck

Antoni Ribas, MD, PhD,  discusses the development process of PD-1 antibody MK-3475 in melanoma.
 

The Developmental Process of MK-3475 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, Ribas explains.

When the immune 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, but some immune cells 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.

Ipilimumab blocks CTLA-4, a negative regulator of the immune system

If the CTLA-4 brake effect is released, immune system cells may be able to target the cancer

Releasing PD-1 is more likely to achieve a rapid response and be more targeted to the T cells that are cancer-specific

The Efficacy of Ipilimumab for the Treatment of Melanoma

Antoni Ribas, MD, PhD, the director of the Tumor Immunology Program Area at UCLA's Jonsson Comprehensive Cancer Center, discusses PD-1 and PD-L1 in various cancers.

PD-1 is a negative regulator of the immune system, preventing it from overactivating. The cancer takes advantage of this, Ribas says, by expressing PD-L1 and preventing an attack from the immune system. New anti-PD-1 and anti-PD-L1 agents re-expose the cancer to the immune system.

Not all cancers and all histologies express PD-L1, Ribas says. PD-L1 has been analyzed in many cancers, including melanoma, kidney cancer, lung cancer, head and neck cancer, and ovarian cancer, allowing for the possibility of broad activity. Agents in this space release a brake of the immune system, meaning that the immune system must be activated against the cancer for these agents to be effective. This remains an evolving paradigm, Ribas notes.

PD-1 is a negative regulator of the immune system

A cancer expresses PD-L1 to prevent an attack from the immune system

Not all cancers and histologies express the ligand PD-L1

Agents in this space release a brake of the immune system

The immune system must be activated against the cancer for these agents to be effective