Oral Selinexor as Maintenance Therapy After First-Line Chemotherapy for Advanced or Recurrent Endometrial Cancer.

PURPOSE: Selinexor inhibits exportin-1 (XPO1) resulting in nuclear accumulation of tumor suppressor proteins including p53 and has clinical activity in endometrial cancer (EC). The primary end point was to assess progression-free survival (PFS) with once-weekly oral selinexor in patients with advanced or recurrent EC. PATIENTS AND METHODS: ENGOT-EN5/GOG-3055/SIENDO was a randomized, prospective, multicenter, double-blind, placebo-controlled, phase III study at 107 sites in 10 countries. Patients 18 years or older with histologically confirmed EC were enrolled. All had completed a single line of at least 12 weeks of taxane-platinum combination chemotherapy and achieved partial or complete response. Patients were assigned to receive 80 mg oral selinexor once weekly or placebo with 2:1 random assignment (ClinicalTrials.gov identifier: NCT03555422). RESULTS: Between January 2018 and December 2021, 263 patients were randomly assigned, with 174 allocated to selinexor and 89 to placebo. The median PFS was 5.7 months (95% CI, 3.81 to 9.20) with selinexor versus 3.8 months (95% CI, 3.68 to 7.39) with placebo (hazard ratio [HR], 0.76 [95% CI, 0.54 to 1.08]; two-sided P = .126), which did not meet the criteria for statistical significance in the intent-to-treat population. Incorrect chemotherapy response stratification data for 7 (2.7%) patients were identified. In a prespecified exploratory analysis of PFS in audited stratification data, PFS for selinexor met the threshold for statistical significance (HR, 0.71; 95% CI, 0.499 to 0.996; two-sided P = .049). Furthermore, patients with the TP53 wild-type (wt) EC had a median PFS of 13.7 and 3.7 months with selinexor and placebo. The most common grade 3 treatment-related adverse events were nausea (9%), neutropenia (9%), and thrombocytopenia (7%). CONCLUSION: The significance level for PFS was only met in the audited analysis. However, a preliminary analysis of a prespecified exploratory subgroup of patients with TP53wt EC showed promising results with selinexor maintenance therapy.

Phase Ib Study of Navicixizumab Plus Paclitaxel in Patients With Platinum-Resistant Ovarian, Primary Peritoneal, or Fallopian Tube Cancer.

PURPOSE: This phase Ib study evaluated the safety and efficacy of paclitaxel plus navicixizumab, a bispecific antiangiogenic antibody to vascular endothelial growth factor and delta-like ligand 4, against platinum-resistant ovarian cancer. PATIENTS AND METHODS: This open-label, nonrandomized, dose-escalation and -expansion study included 44 patients with previously treated, recurrent, platinum-resistant grade 2/3 ovarian cancer. Treatment was intravenous navicixizumab (3 mg/kg or 4 mg/kg once every 2 weeks) plus paclitaxel (80 mg/m2 intravenously on days 0, 7, and 14 of 28-day cycles). The primary and secondary objectives were to evaluate the safety and efficacy of navicixizumab plus paclitaxel. An RNA-based diagnostic panel was retrospectively used to test the hypothesis that tumors with high angiogenesis or immune-suppressed tumor microenvironment (TME) subtypes (biomarker-positive) are more likely to respond to navicixizumab than those with immune-active/-desert TME subtypes (biomarker-negative). RNA expression was analyzed in available pretreatment tumor tissue to classify 33 patients' TME subtypes, and TME panel findings were correlated with tumor response. RESULTS: The dose-escalation cohorts enrolled patients at navicixizumab doses of 3 mg/kg once every 2 weeks (n = 3) and 4 mg/kg once every 2 weeks (n = 2); 3 mg/kg was selected for expansion (n = 39). No dose-limiting toxicities occurred. The most common grade 3/4 treatment-related adverse events were hypertension (40.9%), neutropenia (6.8%), and thrombocytopenia (4.5%). Pulmonary hypertension occurred in 18.2% (grade 1-2). The overall objective response rate was 43.2% (95% CI, 28.3 to 59.0): 33.3% (95% CI, 17.3 to 52.8) in patients previously treated with bevacizumab, 64.3% (95% CI, 35.1 to 87.2) in bevacizumab-naive patients, and 62% (95% CI, 31.6 to 86.1) in biomarker-positive patients. The median duration of response was 6 months (95% CI, 5.4 months to not estimable). CONCLUSION: Navicixizumab plus paclitaxel demonstrated promising clinical activity in bevacizumab-treated and -naive patients with platinum-resistant ovarian cancer, with manageable toxicity.