By Reuters Staff
NEW YORK (Reuters Health) - 2/4/2019
Pembrolizumab (Keytruda, Merck) may have ongoing benefits for people with advanced non-small-cell lung cancer expressing programmed death ligand 1 (PD-L1), extended follow-up of an open-label study shows.
"Pembrolizumab provides durable response and long-term effects on overall survival, with tolerable safety, for treatment naive and previously treated patients with advanced non-small-cell lung cancer expressing PD-L1," Dr. Natasha B. Leighl of Princess Margaret Cancer Centre, in Toronto, Canada, and colleagues report in The Lancet Respiratory Medicine, online March 12.
The new work extends the follow-up from a median of 10.9 months in the original study to about three years. One hundred and one patients were treatment naive and 449 had been previously treated. They were given intravenous pembrolizumab 2 mg/kg every two weeks or 10 mg/kg every two or three weeks until disease progression, intolerable toxicity, investigator decision, or patient withdrawal.
Investigator-assessed objective response according to immune-related response criteria was achieved in 41% of treatment-naive patients and 23% of previously-treated patients.
The median duration of response was 16.7 months in the treatment-naive and 33.3 months in the previously treated. In all, 46% of the former group showed an ongoing response compared to 63% of the latter.
Estimated median overall survival was 22.3 months in the treatment-naive patients and 10.5 months in those previously treated.
Among the 27 treatment-naive patients with a PD-L1 tumor proportion score (TPS) of 50% or greater, median overall survival was 34.9 months compared to 19.5 months in those with a lesser score, a significant difference.
In the 138 previously treated patients with a TPS of 50% or more, survival was 15.4 months compared to 8.5 months in those with a lower score.
Overall, 41% of patients had serious adverse events, and 50 (9%) were treatment related. A total of 30 patients (6%) discontinued owing to a treatment-related adverse event.
In an editorial, Drs. A-M. C. Dingemans and L. E. L. Hendriks of Maastricht University Medical Centre, in the Netherlands, note, "As long-term data on overall survival and toxicity are largely lacking" these results could help to improve selection of patients.
The study, they point out, shows "promising 3-year overall survival data in both previously untreated and previously treated patients with locally advanced or metastatic non-small-cell lung cancer, being most prevalent in responders and patients with a high PD-L1 TPS score."
Merck Sharp & Dohme funded the study and contributed to its design, data analysis and manuscript preparation. A number of the authors have relationships with the company, including employment.
Drs. Leighl did not respond to requests for comments.
Lancet Respir Med 2019.