Pembrolizumab monotherapy continues to show modest antitumor activity in patients with recurrent advanced ovarian cancer, according to updated results of the KEYNOTE-100 study presented at the American Society of Clinical Oncology (ASCO) Annual Meeting (May 29-31, 2020).
In the interim analysis of KEYNOTE-100, patients with recurrent advanced ovarian cancer showed modest clinical activity after treatment with pembrolizumab and a median follow-up of 16.9 months.
Ursula A Matulonis, MD, chief of the division of gynecologic oncology, Dana-Farber Cancer Institute (Boston, MA), and colleagues presented the results of the protocol-specific final analysis of KEYNOTE-100 based on a data cutoff of September 18, 2019. Among the eligibility criteria for patients were epithelial ovarian, fallopian tube, or primary peritoneal cancer; confirmed recurrence following front-line platinum-based therapy; ECOG performance status of 0-1; and provision of a tumor sample for biomarker analysis. Patients were divided into two cohorts – those in Cohort A (n = 285) received two or less lines of prior chemotherapy for recurrent advanced ovarian cancer and had a platinum-free or treatment-free interval of at least 3 to 12 months, and patients in Cohort B (n = 91) received three to five lines of prior chemotherapy and had a platinum-free or treatment-free interval of at least 3 months.
Tumor imaging was performed every 9 weeks for 12 months and every 12 weeks thereafter, researchers noted. The primary endpoint of the study was ORR per RECIST v1.1 by independent central review in both cohorts and by tumor PD-L1 expression using the combined positive score.
Dr Matulonis and colleagues found that in Cohorts A and B, ORR was 8.1% and 9.9%, respectively, in the total population; 6.9% and 10.2%, respectively, in patients with a combined positive score of at least 1; and 11.6% and 18.2%, respectively, in patients with a combined positive score of at least 10. Median duration of response was 8.3 months and 23.6 months, respectively, they added.
Additionally, researchers reported that median progression-free survival was 2.1 months in both cohorts. Median overall survival was 18.7 months and 17.6 months, respectively, in the total population; 20.6 months and 20.7 months, respectively, in patients with a combined positive score of at least 1; and 21.9 months and 24.0 months, respectively, in patients with a combined positive score of at least 10.
“Pembrolizumab monotherapy was associated with modest antitumor activity in patients with recurrent advanced ovarian cancer,” authors of the study concluded. “There appeared to be a trend toward increased ORR with higher PD-L1 expression in both cohorts.”
No new safety signals were identified in the final analysis, they added.—Zachary Bessette
