(Adds stock move)
By Bill Berkrot
May 29 (Reuters) - A Merck & Co drug that helps the immune system fight cancer was about twice as effective as the current standard therapy for patients with recurrent or advanced head and neck cancers, according to study data released on Friday.
A quarter of the 132 patients who received the drug, Keytruda (pembrolizumab), saw their tumors shrink by at least 30 percent. Fifty-six percent of patients experienced at least some tumor shrinkage in the ongoing single drug Phase I study dubbed Keynote-012, researchers reported.
“This is remarkable because we don’t usually see this level of activity with new agents. We have a track record of failure,” said Dr. Tanguy Seiwert, lead investigator of the study from the University of Chicago.
Advanced head and neck cancer is currently treated with Eli Lilly’s Erbitux, known chemically as cetuximab, which typically has a response rate of 10 percent to 13 percent.
“The only thing that works is cetuximab and this looks at least twice as good,” said Seiwert, who was presenting the Keytruda data at the American Society of Clinical Oncology meeting in Chicago.
Merck shares rose more than 1 percent to $60.43 on the New York Stock Exchange.
Keytruda and Opdivo from Bristol-Myers Squibb Co are at the forefront of a promising new class of drugs called PD-1 inhibitors that block a mechanism tumors use to evade the immune system. Keytruda is approved to treat advanced melanoma and awaits a decision for use in lung cancer. It is being tested against 30 types of cancer alone and in various combinations.
While overall survival data was not yet available, Keytruda and Opdivo have extended survival for some patients in other cancers.
“Response rate doesn’t do this justice,” Seiwert said. “A fraction of those patients will probably have long term survival. It can really make a difference for some patients who have incurable metastatic disease.”
The drug appeared to work as well for patients whose cancer tested positive for human papillomavirus as those who were HPV negative. Some older treatments may be less effective in HPV positive patients, researchers said.
Keytruda was well tolerated with few side effects, Seiwert said. Serious immune-related side effects, such as inflammation of the lungs or colon, were reported in a very small number of patients in the study.
Head and neck cancer is the sixth most common cancer worldwide. Patients with recurrent or metastatic head and neck cancer are usually expected to live about 10 to 12 months.
Reporting by Bill Berkrot in New York; Editing by Diane Craft