The checkpoint inhibitor pembrolizumab (Keytruda) offers patients with advanced head and neck cancers longer survival time, according to researchers led by the Yale Cancer Center (YCC). Overall survival was significantly improved through a phase 3 study for participants with previously untreated recurrent or metastatic head and neck cancers, compared to the standard therapy.
“This research demonstrates that use of this checkpoint inhibitor, with or without chemotherapy, should be the first drug used for these types of cancers,” said lead investigator Barbara Burtness, MD, professor of medical oncology and coleader of developmental therapeutics at YCC. “This is a very positive advance in treatment for our patients.”
Early results from this clinical trial, KEYNOTE-048, led to US Food and Drug Administration approval earlier this year of pembrolizumab as first-line therapy in untreated, recurrent, or metastatic head and neck cancers. Cancers specifically known as head and neck squamous-cell carcinoma (HNSCC) include cancers or the oral cavity, oropharynx, hypopharynx, and larynx.
While median survival benefit was calculated in months, some patients treated with pembrolizumab lived much longer and did significantly better than patients who were not treated with the checkpoint inhibitor, Burtness said.
Overall survival was calculated in 882 participants enrolled in 200 medical centers in 37 countries who were randomized to one of three different groups: pembrolizumab (301 patients), pembrolizumab and chemotherapy (281), or standard therapy with cetuximab and chemotherapy (300). Cetuximab is a drug designed to shut down a protein that makes cancer cells more responsive to growth factors. The chemotherapy used was platinum and 5-fluorouracil.
Pembrolizumab used alone improved median survival to 14.9 months, compared to 10.7 months for standard therapy. The use of pembrolizumab combined with chemotherapy improved survival to a median of 13 months. Also, survival differences between patients treated with pembrolizumab and those who weren’t remained very apparent years after treatment.
At three years, 33% of patients treated with pembrolizumab monotherapy were alive, as well as about 26% of participants in the pembrolizumab/chemotherapy groups, compared with only 8% in the standard treatment arm. Toxicity was reduced in patients treated with pembrolizumab monotherapy, and participants in the other two groups experienced about the same level of adverse effects.
“The difference with immunotherapy is the durability of the effect it has on survival,” said Burtness. “These agents seem to change the tumor microenvironment, altering the natural history of the cancer.”
The study was published by The Lancet.