New type drug for deadly skin cancer improved long-term survival

A new kind of drug for the deadliest form of skin cancer helped some patients survive for at least three years, a study shows.

That’s a remarkable advance for patients who, until recently, faced dismal chances of living for more than a few months.

About 40 percent of melanoma patients in the study were still alive three years later.

The drug, Keytruda, which targets the immune system, was used to treat former President Jimmy Carter, who was diagnosed with melanoma that had spread to his brain.

“This is incredible,” Dr. Caroline Robert, the study’s lead author, says of the results. “I spend my time telling my residents that these patients would be dead if it was five years ago.”

Keytruda is among a new class of genetically engineered antibody-based medicines. They block proteins that prevent the body’s disease-fighting immune system from attacking cancer cells. This immunotherapy approach is transforming treatment for several kinds of cancer with drugs that are often less toxic than chemotherapy.

The Keytruda study was released at a news briefing organized by the American Society of Clinical Oncology in advance of the group’s annual meeting next month in Chicago.

The findings for Merck’s Keytruda (kee-TROO’-duh) — its generic name is pembrolizumab (pem-bro-LIZ’-uh-mab) — are among the best long-term data ever for treating melanoma that’s spread to other organs, Robert and other cancer experts say.

The results from 655 patients are a follow-up to research that led to the 2014 approval of Keytruda for advanced melanoma. In addition to the 40 percent survival rate at three years, Robert says 85 patients remain cancer-free.

“Of course, it’s not enough,” but it raises hope for an eventual cure, she says.

Robert, a melanoma researcher at Gustave Roussy cancer center near Paris, has worked as a consultant for Merck and Bristol-Myers Squibb, which makes two other immunotherapy drugs approved for advanced melanoma. The newest — Opdivo — targets the same protein as Keytruda. Yervoy targets a different protein.

Yervoy, approved in 2011, has the longest-term data of the drugs, with an eight-year survival rate of about 20 percent, says three Dr. Thomas Gajewski, a University of Chicago immunotherapy expert.

Gajewski says the success with Keytruda echoes what he’s seen in melanoma patients. They get IV infusions of the drug for an hour every few weeks for an indefinite time unless they develop severe side effects, which he says are rare and reversible if the drug is stopped.

The yearly cost — more than $100,000 — is higher than some conventional cancer drugs. But some insurers now cover the treatment, which Gajewski calls “a game-changer” for melanoma, allowing many patients to return to work and live productive lives.