Pembrolizumab exhibits antitumor activity in advanced nasopharyngeal carcinoma
Pembrolizumab demonstrated antitumor activity and a manageable safety profile among patients with recurrent or metastatic nasopharyngeal carcinoma that expressed PD-L1, according to results from the KEYNOTE-028 clinical trial.
“Prognosis for patients with recurrent or metastatic nasopharyngeal carcinoma — accounting for approximately 10% of all cases — is poor,” Chiun Hsu, MD, PhD, professor in the graduate institute of oncology at National Taiwan University Hospital, and colleagues wrote. “The present study demonstrates that pembrolizumab [Keytruda, Merck] monotherapy has promising antitumor activity and a manageable safety profile in patients with PD-L1-positive recurrent or metastatic nasopharyngeal carcinoma.”
A reported 89% to 95% of nasopharyngeal carcinomas have PD-L1 expression. Pembrolizumab — a potent and highly selective humanized monoclonal antibody that directly blocks the interaction between PD-1 and PD-L1 — has demonstrated antitumor activity in various tumor types.
In KEYNOTE-028, Hsu and colleagues explored the safety and antitumor activity of pembrolizumab in 20 types of advanced malignances, including nasopharyngeal carcinomas. Twenty-seven patients (median age, 52 years; range, 18-68) with PD-L1-positive advanced nasopharyngeal carcinoma who failed previous standard therapy received 10 mg/kg pembrolizumab every 2 weeks up to 2 years or until disease progression or unacceptable toxicity. The researchers measured tumor response via RECIST every 8 weeks for the first 6 months and every 12 weeks thereafter.
Objective response rate served as the primary endpoint. Secondary endpoints included PFS, OS, duration of response, safety and tolerability.
Most patients (92.6%) received prior therapy; 70.4% received three or more therapies.
Over a median follow-up of 20 months, partial response occurred in seven patients and stable disease in 14 patients, indicating an ORR of 25.9% (95% CI, 11.1-46.3). Central review showed a similar ORR at 26.3%.
Adverse events related to pembrolizumab occurred in 15% or more of patients. Common adverse events included rash (25.9%), pruritus (25.9%), pain (22.2%), hypothyroidism (18.5%) and fatigue (18.5%).
Grade 3 or worse drug-related adverse events occurred in eight patients (29.6%). One drug-related death occurred from sepsis.
At the study cutoff, three patients had completed 2-year pembrolizumab therapy and two remained on the study. Twenty-two patients discontinued treatment due to progressive disease (48%), adverse events (18.5%), physician decision (7.4%) and patient withdrawal (7.4%). – by Melinda Stevens
Disclosures: Hsu reports honoraria from Bayer Schering Pharma, Merck and TTY Biopharm; research funding from Celgene; and other expenses from Bayer Schering Pharma, Bristol-Myers Squibb and TTY Biopharm. Please see the full study for a list of all other researchers’ relevant financial disclosures.