Avelumab had antitumor activity and acceptable safety in heavily pretreated ovarian cancer patients enrolled in a large phase 1b trial, investigators have reported.
Treatment with the anti–programmed death-ligand 1 (anti–PD-L1) agent yielded an overall response rate of 9.6%, with a median duration of response exceeding 10 months and median overall survival greater than 11 months, according to investigators in the JAVELIN Solid Tumor trial.
There was no association between PD-L1 or BRCA status and response, which is a novel finding, investigators wrote in JAMA Oncology.
“Very few patients had tumors with high-level PD-L1 expression, which is associated with an increased probability of clinical benefit with anti–PD-1 or anti–PD-L1 treatment of non–small cell lung cancer,” said the investigators, led by Mary L. Disis, MD, of the Cancer Vaccine Institute at the University of Washington, Seattle.
The phase 1b, global, open-label study included 125 women with stage III or IV epithelial ovarian, fallopian tube, or peritoneal cancer who had recurrent or refractory disease and had received a median of three previous treatments for locally advanced or metastatic disease.
All patients received avelumab 10 mg/kg in a 1-hour intravenous infusion every 2 weeks until disease progression, unacceptable toxicity, or other protocol-defined criteria for study withdrawal.
Confirmed objective responses were seen in 12 patients, or 9.6%, including one complete response and 11 partial responses, the investigators reported. Another 53 patients, or 42.4%, had stable disease as their best response, for a combined disease control rate of 52.0%.
Median progression-free survival was 2.6 months, and median overall survival was 11.2 months, with a 12-month overall survival rate of 47.0%, investigators said.
Responses occurred irrespective of PD-L1 expression status, according to investigators, with no discernible trends in response looking at different PD-L1 expression cutoffs for tumor cells.
For example, at a PD-L1 expression cutoff of 5% or more, patients with positive tumors had an overall response rate of 12.5%, median progression-free survival of 2.7 months, and median overall survival of 10.6 months, they reported, while among negative patients, overall response rate was 9.8%, and median progression-free and overall survival were 2.2 and 11.9 months, respectively.
Treatment-related adverse events occurred in 86 patients, or 68.8%, of which infusion-related reactions and related symptoms were the most common, occurring in 25 patients (20%), investigators wrote. Immune-related adverse events were seen in 16.8% of patients, including three patients (2.4%) with grade 3, and zero with grade 4 or 5.
These findings track with results of other checkpoint inhibitor monotherapy trials in advanced, previously treated ovarian cancer, including smaller studies of pembrolizumab and nivolumab with overall response rates of 11.5% and 15.0%, respectively, according to investigators.
“Although response and survival findings with avelumab monotherapy in this study are encouraging, it would be of interest to determine whether efficacy can be increased through combination or sequential regimens involving chemotherapy or PARP [poly ADP-ribose polymerase] inhibitors,” said the investigators.
Combination studies are underway in women with ovarian cancer, including two global phase 3 trials evaluating avelumab plus chemotherapy in the first-line setting and in patients with platinum-resistant or platinum-refractory disease.
“Results from these ongoing studies will help to define an appropriate role for checkpoint inhibitors within the treatment of ovarian cancer,” study authors concluded.
The JAVELIN trial is sponsored by Merck KGaA as part of an arrangement between the company and Pfizer. Dr. Disis reported disclosures related to Celgene, EMD Serono, Epithany, Janssen, Pfizer, and Seattle Genetics. Coauthors reported disclosures with Merck, Blueprint, Bristol-Myers Squibb, Eisai, Loxo, Novartis, and others.
SOURCE: Disis ML et al. JAMA Oncol. 2019 Jan 24. doi: 10.1001/jamaoncol.2018.6258.
