Carboplatin, paclitaxel, and pembrolizumab followed by pembrolizumab maintenance for primary treatment of incompletely resected epithelial ovarian cancer.

Objective: Incompletely resected epithelial ovarian cancer represents a poor prognostic subset of patients. Novel treatment strategies are needed to improve outcomes for this population. We evaluated a treatment strategy combining platinum-based chemotherapy with pembrolizumab followed by pembrolizumab maintenance therapy in the first-line treatment after incomplete resection of epithelial ovarian cancer patients. Methods: This was a single-arm, non-randomized pilot study of carboplatin, taxane, and immune checkpoint inhibitor, pembrolizumab, followed by 12 months of maintenance pembrolizumab in patients with incompletely resected epithelial ovarian cancer (EOC). Results: A total of 29 patients were enrolled and evaluated for efficacy and safety. The best response to therapy was complete response in 16 (55%) patients, partial response in 9 (31%) patients, and 3 (10%) patients with progression of disease. The median progression-free survival (PFS) was 13.2 months. Grade 3 and 4 toxicities occurred in 20% of patients. In all, 7 patients discontinued therapy due to adverse events. Quality-of-life scores remained high during therapy. Response to therapy did not correlate with PD-L1 tumor expression. Conclusions: Combination platinum-taxane therapy with pembrolizumab did not increase median progression-free survival in this cohort of patients. Key message: EOC is an immunogenic disease, but immune checkpoint inhibitor therapy has yet to impact outcomes. The current study utilized pembrolizumab in combination with standard chemotherapy followed by a maintenance treatment strategy in incompletely resected EOC. Progression-free survival was not extended in this poor prognostic group with combined chemotherapy and immunotherapy. Clinical trial registration: https://clinicaltrials.gov/, identifier NCT 027766582.

Targeting regulatory T cells by E7777 enhances CD8 T-cell-mediated anti-tumor activity and extends survival benefit of anti-PD-1 in solid tumor models.

Introduction: Regulatory T cell (Treg)-targeting cancer immunotherapy aims to transiently deplete Treg cells in the tumor microenvironment, without affecting effector T cells (Teff), thus both enhancing anti-tumor activity and avoiding autoimmunity. This study evaluated whether adding E7777 (a new formulation of denileukin diftitox [DD]) improved the efficacy of anti-PD-1 antibody therapy. DD is a recombinant protein containing the hydrophobic and catalytic portions of diphtheria toxin fused to full-length human IL-2. E7777 has the same amino acid sequence and brief circulatory half-life as DD, but with greater purity and potency. Methods: Subcutaneous syngeneic murine solid tumor models (colon cancer CT-26 and liver cancer H22) were used to evaluate safety, efficacy, and overall survival with E7777 and anti-PD-1 antibodies, each administered as monotherapy or in concurrent or sequential combination. In Experiment 1, treatments were compared to assess anti-tumor activity at various time points, with tumors excised and dissociated and tumor leukocytes characterized. In Experiment 2, tumor growth, response, and overall survival were characterized for 100 days following a 3-week treatment. Results: E7777 administered in combination with anti-PD-1 led to significantly increased anti-tumor activity and durable, extended overall survival compared to either treatment alone. In both tumor models, the Treg cell infiltration induced by anti-PD-1 treatment was counterbalanced by co-treatment with E7777, suggesting potential synergistic activity. Combination therapy showed the most favorable results. Treatment with E7777 was safe and well-tolerated. Discussion: Combined E7777 and anti-PD-1 therapy was well tolerated and more effective than monotherapy with either drug.

Clinical and pathologic characteristics of serous carcinoma confined to the endometrium: a multi-institutional study.

The objective of this study was to analyze the clinical and pathologic factors in patients with uterine serous carcinoma confined to the endometrium. A total of 236 uterine serous carcinoma patients from the pathology databases of 4 large academic institutions were included in the study. Clinical and pathologic variables were analyzed, including patient demographics, tumor size (≤2 vs. >2 cm), myometrial invasion, lymphovascular invasion, lymph node status, tumor location (endometrium vs. polyp), cervical involvement, lower uterine segment involvement, FIGO stage, pelvic washings, recurrence, overall survival, and progression-free survival. Of 236 patients, 55 (23%) had tumors limited to the endometrium. Forty-four patients (80%) had Stage IA tumors. The tumor was confined to a polyp in 17 (30.9%) patients. Twenty patients (36.4%) had tumor sizes >2 cm and 12 (21.8%) exhibited lymphovascular invasion. Only 3 patients (5.4 %) had cervical stromal involvement. Thirty-three (66%) patients underwent pelvic and para-aortic lymphadenectomy with 2 positive para-aortic lymph nodes identified. Seven (12.7%) patients had positive washings, whereas 8 patients (14.5 %) had disease recurrence. At a median follow-up of 46 months, there was no difference in overall survival (P = 0.216) or progression-free survival (P=0.063) between patients with tumors confined to a polyp, patients with tumors confined to the endometrium, and patients with tumors present in both polyp and the endometrium. Uterine serous carcinoma with only endometrial involvement, even when confined to a polyp, can be associated with poor prognosis, further stressing the importance of complete surgical staging and adjuvant treatment in this setting.