Good news for head and neck cancer patients

Good news for head and neck cancer patients

30 May 2015

The tumor checkpoint inhibitor pembrolizumab (Keytruda) appears to shrink cancer in as many as 25% of advanced head and neck cancer patients, researchers said in reporting the late-breaker trial results.

Patient eligibility for this study

Patients were eligible for the study if they had been diagnosed with recurrent or metastatic head and neck squamous cell cancer; had measurable cancer and an ECOG performance status of 0-1. They were treated with pembrolizumab, humanized monoclonal antibody against PD-1 protein, which stops immune competent cells from attacking aberrant or cancer cells.

Tanguy Seiwert, MD, assistant professor of medicine at the University of Chicago said that that 59% of the patients in the study had received at least 2 lines of prior therapy. Patients were included without testing for PD-L1 status, a possible biomarker which could determine how well an immunotherapeutic agent such as pembrolizumab might work.

Treatment was scheduled for 24 months until documented disease progression or intolerable toxicity.

“The largest experience of immunotherapy in head and neck cancer”

According to Seiwert, of the patients in the study who were treated without regard to biomarker status,

• Objective responses to treatment -- more than a 30% reduction in size of solid tumors -- were observed in 24.8% of patients, including one patient who achieved a complete response.
• 20.6% of the 34 evaluable patients who tested positive for human papilloma virus responded to treatment, and 27.2% of the 81 evaluable patients who tested negative for human papilloma virus responded to treatment.
• Overall, however, 56% of the patients in the trial showed some reduction in tumor size -- although not reaching the milestone for being considered a partial or complete response, Seiwert said.

"This was the largest experience of immunotherapy in head and neck cancer," he said, adding that “the drug is highly active in pretreated population. Moreover the responses observed in the trial appeared to be durable, with 86% of those who responded to therapy continuing to some clinical benefit from treatment”.

The drug was well tolerated. In fact, less than 10% of the patients in the trial experienced a grade 3 or greater adverse event.

“Too early to use it outside of a clinical trial”

In commenting on the study, Roy Herbst, MD, PhD, chief of medical oncology at Yale Cancer Center said that although, "these are promising early results, I think it is too early to use this drug in these patients outside of a clinical trial.”

Herbst suggested that the treatment with pembrolizumab should also be considered earlier in the disease course, especially since it appears less toxic than chemotherapy and radiation therapy.  

Source: MedPage Today