Improvements in response rates and progression-free survival were observed with the addition of PD-1 antibody pembrolizumab to standard first-line chemotherapy for non-small-cell lung cancer (NSCLC) treatment.
“Pembrolizumab enables T cells to ‘reactivate’ and accomplish what they are designed to do — facilitate tumour cell killing,” said principal investigator Dr Corey Langer, director of the Thoracic Oncology Program at the Abramson Cancer Center at the University of Pennsylvania, US.
In the phase II KEYNOTE-021 study, researchers randomized 123 patients with stage IIIB/IV, chemotherapy-naive, nonsquamous non-small-cell lung cancer to receive four cycles of carboplatin and pemetrexed (500 mg/m2 every three weeks), with or without 24 months treatment with pembrolizumab (200mg every three weeks).
After a median follow-up of 10.6 months, researchers observed a significantly greater objective response rate (55% vs. 29%, P = 0.0016) in the patients who received pembrolizumab as well as chemotherapy, compared to those treated with chemotherapy alone. While patients were not selected by the amount of PD-L1 expression in their tumour, researchers did note a higher response rate (around 80%) for the pembrolizumab and chemotherapy combination in tumours with PD-L1 expression greater than or equal to 50%.
Participants in the pembrolizumab arm also experienced an improved progression-free survival (median 13.0 months vs. 8.9 months) although overall survival rates were similar between the two arms (6 month survival rate = 92%), in this early landmark assessment.