Targeted drug combo shows promise against melanoma

* 81 percent of patients responded to treatment

* Fewer toxicities seen with combination therapy

By Deena Beasley

CHICAGO (Reuters) – The combination of two experimental pills developed by GlaxoSmithKline Plc has shown promise as a treatment for melanoma, the most deadly type of skin cancer, according to new research.

The early stage trial involved patients with advanced melanoma with a specific genetic mutation who were treated with drugs designed to block MEK (GSK212) and BRAF (GSK436), two components of the same pathway used by the cancer to drive tumor growth.

Out of the 16 patients so far evaluated in the study, 13 percent had tumor shrinkage, and three had stable disease, for an overall response rate of 81 percent.

The researchers said combining the drugs resulted in fewer skin reactions such as cutaneous squamous cell carcinoma, another type of skin cancer, and rashes, compared with use of each drug on its own.

“The take-home message is we were able to give both drugs together and the combination improved some of the troublesome toxicities,” Dr. Jeffrey Infante, director of drug development at the Sarah Cannon Research Institute in Nashville, Tennessee, told reporters at the American Society of Clinical Oncology meeting in Chicago.

“The majority of patients have a clinical benefit from the regimen quickly,” Infante said at a press briefing.

So far, five patients have had their tumors disappear, he said, adding, “You don’t have to be an oncologist to know you are helping people.”

A midstage trial of the Glaxo drugs is currently underway.

Unlike traditional chemotherapy drugs, which work by interfering with the entire body’s system of cell replication, newer targeted drugs aim to block specific pathways that cancer cells use to grow and reproduce.

“This is one of the first studies where two of these new targeted therapies are combined,” ASCO Chief Executive Dr. Allen Lichter said in a telephone briefing.

Since most tumors eventually find a way to get around blocked pathways, “there is widespread understanding that we are going to need to learn how to combine two or more targeted therapies to block the main road and the side road and the dirt road,” he said.