This open-label, non-comparative, 2:1 randomized, phase II trial (NCT03275506) in women with stage IIIC/IV high-grade serous carcinoma (HGSC) for whom upfront complete resection was unachievable assessed whether adding pembrolizumab (200 mg every 3 weeks) to standard-of-care carboplatin plus paclitaxel yielded a complete resection rate (CRR) of at least 50%. Postoperatively patients continued assigned treatment for a maximum of 2 years. Postoperative bevacizumab was optional. The primary endpoint was independently assessed CRR at interval debulking surgery. Secondary endpoints were Completeness of Cytoreduction Index (CCI) and peritoneal cancer index (PCI) scores, objective and best response rates, progression-free survival, overall survival, safety, postoperative morbidity, and pathological complete response. The CRR in 61 pembrolizumab-treated patients was 74% (one-sided 95% CI = 63%), exceeding the prespecified ≥50% threshold and meeting the primary objective. The CRR without pembrolizumab was 70% (one-sided 95% CI = 54%). In the remaining patients CCI scores were ≥3 in 27% of the standard-of-care group and 18% of the investigational group and CC1 in 3% of the investigational group. PCI score decreased by a mean of 9.6 in the standard-of-care group and 10.2 in the investigational group. Objective response rates were 60% and 72%, respectively, and best overall response rates were 83% and 90%, respectively. Progression-free survival was similar with the two regimens (median 20.8 versus 19.4 months in the standard-of-care versus investigational arms, respectively) but overall survival favored pembrolizumab-containing therapy (median 35.3 versus 49.8 months, respectively). The most common grade ≥3 adverse events with pembrolizumab-containing therapy were anemia during neoadjuvant therapy and infection/fever postoperatively. Pembrolizumab was discontinued prematurely because of adverse events in 23% of pembrolizumab-treated patients. Combining pembrolizumab with neoadjuvant chemotherapy is feasible for HGSC considered not completely resectable; observed activity in some subgroups justifies further evaluation to improve understanding of the role of immunotherapy in HGSC.

Immune checkpoint inhibitors improve the treatment of many solid tumors and have shown encouraging results in advanced squamous cell carcinoma (SCC), yet only a minority of patients respond to immune checkpoint inhibitor monotherapy. We conducted the PEVOsq trial, an open-label, nonrandomized, multicenter, basket phase 2 trial to evaluate the combination of pembrolizumab and vorinostat in recurrent/metastatic SCC of various origins. The primary endpoint was the objective response rate (ORR) in each tumor cohort during treatment as per the investigators’ assessment. Secondary endpoints included safety and antitumor activity evaluation in terms of centrally confirmed ORR, progression-free survival, overall survival and duration of response. In the efficacy population (n = 107), the ORR was met in cervical (39%), anal (31%) and vulvar/vaginal (19%) cancer cohorts, but not in head and neck SCC (19%) or penile (18%) cancer cohorts (overall ORR = 26%). Median progression-free survival was 4.0 months (95% confidence interval: 2.6–4.3), and median overall survival was 11.1 months (95% confidence interval: 9.2–17.4). In the safety population, 101 (91%) of 111 patients developed at least one treatment-related adverse event, with 39% and 5.4% of patients experiencing at least one grade 3 and grade 4 treatment-related adverse event, respectively. Vorinostat-related toxicity prompted a dose reduction/interruption in 66% of patients. Whole-exome sequencing analyses revealed several potential predictive biomarkers of response to treatment. Further studies in a larger number of patients are required to validate these findings. ClinicalTrials.gov identifier: NCT04357873.

PD-1/PD-L1 blockade has so far shown limited survival benefit for high-grade ovarian carcinomas. By using paired samples from the NeoPembrOv randomized phase II trial (NCT03275506), for which primary outcomes are published, and by combining RNA-seq and multiplexed immunofluorescence staining, we explore the impact of NeoAdjuvant ChemoTherapy (NACT) ± Pembrolizumab (P) on the tumor environment, and identify parameters that correlated with response to immunotherapy as a pre-planned exploratory analysis. Indeed, i) combination therapy results in a significant increase in intraepithelial CD8⁺PD-1⁺ T cells, ii) combining endothelial and monocyte gene signatures with the CD8B/FOXP3 expression ratio is predictive of response to NACT + P with an area under the curve of 0.93 (95% CI 0.85-1.00) and iii) high CD8B/FOXP3 and high CD8B/ENTPD1 ratios are significantly associated with positive response to NACT + P, while KDR and VEGFR2 expression are associated with resistance. These results indicate that targeting regulatory T cells and endothelial cells, especially VEGFR2⁺ endothelial cells, could overcome immune resistance of ovarian cancers.

Peer reviewed article authored by (Hamizi S, Freyer G, Bakrin N, Henin E, Mohtaram A, Le Saux O, Falandry C). Read article or submit your manuscript for publishing.