Breakthrough in Fighting Skin & Lung Cancers

Researchers at UCLA’s Jonsson Comprehensive Cancer Center are reporting promising treatment milestones for patients with deadly skin and lung cancers who are being treated with an experimental drug called MK-3475.

A release from the university written by Shaun Mason reports that the drug is an antibody that targets a protein known as PD-1, which is expressed by immune cells. In the body, PD-1 acts as an immune checkpoint, tamping down the activity of T cells that would otherwise attack cancer cells. MK-3475 “takes the brakes off, allowing T cells to identify and attack cancer cells”, the release states.

In May 2013, MK-3475 received a “breakthrough therapy” designation under the U.S. Food and Drug Administration’s accelerated approval program for the treatment of melanoma that has metastasized or is not removable through surgery.

In clinical trials at UCLA, doctors are seeing major treatment successes with MK-3475 in two types of cancer with historically low survival rates: metastatic melanoma, a malignant skin cancer that spreads aggressively to vital organs such as the brain, lungs ,and liver, and lung cancer, which causes the highest number of cancer deaths in the U.S. annually.

The findings were presented in June 2014 at the American Society of Clinical Oncology conference in Chicago.

Dr. Antoni Ribas, a professor of hematology–oncology and member of the Jonsson Cancer Center, led one of the largest Phase 1 studies in cancer, with 411 patients who had metastatic melanoma, which has an average five-year survival rate of less than 5 percent. The one-year overall survival rate was 69 percent for all patient subgroups.

Response to MK-3475 — that is, individuals whose tumors shrank — was continuing in 88 percent of patients at the time the study was analyzed, generally at 12-month follow-up. Tumors responded in patients on various dose regimens and in various subgroups, including those whose cancers had worsened on the drug ipilimumab; there are currently no treatment options with proven activity for these patients.

The release quotes Ribas as saying, “We are seeing unprecedented durable responses with this drug. MK-3475 is working in patients who had not been treated, as well as those who had been given ipilimumab and other therapies. These are early data, but response rates of this magnitude in such a large sample, with only 4 percent of patients discontinuing because of drug-related side effects, indicate the importance of moving forward quickly with this drug.”

Overall, 34 percent of patients had responses to MK-3475, including 40 percent who had not been treated with ipilimumab and 28 percent whose cancer worsened despite ipilimumab treatment. Treatment-related side effects were generally mild and reversible; 8 perceNon–small-sell lung cancer