OA03.07 KEYNOTE-010: Durable Clinical Benefit in Patients with Previously Treated, PD-L1-Expressing NSCLC Who Completed Pembrolizumab

Abstract

Checkpoint inhibitors such as the anti–PD-1 monoclonal antibody pembrolizumab have demonstrated antitumor activity and a manageable safety profile in several advanced malignancies. Although checkpoint inhibitors are rapidly becoming a standard-of-care therapy in multiple tumor types, the optimal treatment duration has not been established. We plan to assess outcomes in patients who completed the maximum 24 months of pembrolizumab in the phase 3 KEYNOTE-010 study (NCT01905657), in which pembrolizumab provided superior OS over docetaxel in patients with previously treated, PD-L1–expressing advanced NSCLC. 1034 patients with advanced NSCLC that progressed after ≥2 cycles of platinum-based chemotherapy (and an appropriate therapy for targetable EGFR and ALK aberrations if present) and had a PD-L1 tumor proportion score ≥1% were randomized 1:1:1 to pembrolizumab 2 or 10 mg/kg Q3W or to docetaxel 75 mg/m2 until disease progression, intolerable toxicity, physician or patient decision; the maximum duration of pembrolizumab was 24 months of uninterrupted treatment or 35 cycles, whichever was later. Response was assessed per RECIST v1.1 every 9 weeks. After completion of 24 months/35 cycles, patients continued to undergo imaging every 9 weeks; patients with subsequent disease progression were eligible for a second treatment course if they did not receive other anticancer therapy after stopping pembrolizumab. Reason late-breaking status required: As of the most recent analysis, which had a data cutoff date of March 31, 2016, and a median follow-up of 19.2 months (range, 11.7-29.7), only 3 patients in each pembrolizumab arm completed 24 months/35 cycles of treatment. At the time of the next data analysis, which is planned for September 2016, we expect ≥35 patients to have reached the 24-month/35-cycle plateau, allowing for a more robust analysis. Anticipated data: We anticipate providing the following for patients who completed 24 months/35 cycles of pembrolizumab: best overall response, ORR, time to response, and duration of response to first-course therapy; time since the last pembrolizumab dose; incidence of death and disease progression after stopping pembrolizumab; and frequency of second-course initiation.