Assessment of Combined Nivolumab and Bevacizumab in Relapsed Ovarian Cancer: A Phase 2 Clinical Trial

To date, single-agent programmed cell death 1 protein 1 (PD-1)/programmed death ligand 1 (PD-L1) immune checkpoint blockade has shown limited activity in recurrent epithelial ovarian cancer. Combination strategies of PD-1/PD-L1 inhibition with antiangiogenic therapy have the potential for synergistic activity through modulation of the microenvironment and represent a potential therapeutic opportunity in this disease.

To evaluate the activity of combined nivolumab and bevacizumab in women with relapsed ovarian cancer.

A single-arm, phase 2 study enrolled patients between February 8, 2017, and December 29, 2017, at 2 sites in the United States; the primary data analysis was completed July 27, 2018. Thirty-eight women with relapsed epithelial ovarian cancer were enrolled in this study. Participants had disease recurrence within 12 months of their last platinum-based therapy and had received between 1 and 3 lines of prior therapy.

Participants received intravenous nivolumab and intravenous bevacizumab once every 2 weeks.

The primary end point was objective response rate (ORR) as measured by Response Evaluation Criteria in Solid Tumors 1.1. Secondary end points included evaluation of the ORR by platinum sensitivity, assessment of progression-free survival, assessment of safety data, and investigation of the association of tumor PD-L1 with response to therapy.

Of the 38 women enrolled, 18 had platinum-resistant and 20 had platinum-sensitive disease; mean (SD) age was 63.0 (9.1) years. Eleven patients experienced a confirmed response to nivolumab with bevacizumab (ORR, 28.9%; 95% exact binomial CI, 15.4%-45.9%), with 1 additional unconfirmed response. The ORR was 40.0% (19.1%-64.0%) in platinum-sensitive and 16.7% (95% CI 3.6%-41.4%) in platinum-resistant participants. Thirty-four participants (89.5%) experienced at least 1 treatment-related adverse event; 9 participants (23.7%) experienced a grade 3 or higher treatment-related adverse event. Median progression-free survival was 8.1 months (95% CI, 6.3-14.7 months). In 36 histologic samples for which PD-L1 testing could be performed, 22 samples (61.1%) had a PD-L1 tumoral percentage less than 1, and 14 samples (38.9%) had a PD-L1 tumoral percentage of 1 or greater. Ten responses occurred in patients with PD-L1 tumor percentage less than 1, and 2 in patients with PD-L1 tumor percentages of 1 or greater.

The nivolumab with bevacizumab combination appeared to show activity in patients with relapsed ovarian cancer, with greater activity in the platinum-sensitive setting. Alternative combinational strategies may be necessary in the platinum-resistant setting.