Christof Vulsteke

Progression-free survival and safety at 3.5 years of follow-up: results from the randomised phase 3 PRIMA/ENGOT-OV26/GOG-3012 trial of niraparib maintenance treatment in patients with newly diagnosed ovarian cancer

To report updated long-term efficacy and safety from the double-blind, placebo-controlled, phase 3 PRIMA/ENGOT-OV26/GOG-3012 study (NCT02655016). Patients with newly diagnosed advanced ovarian cancer with complete or partial response (CR or PR) to first-line platinum-based chemotherapy received niraparib or placebo once daily (2:1 ratio). Stratification factors were best response to first-line chemotherapy regimen (CR/PR), receipt of neoadjuvant chemotherapy (yes/no), and homologous recombination deficiency (HRD) status (deficient [HRd]/proficient [HRp] or not determined). Updated (ad hoc) progression-free survival (PFS) data (as of November 17, 2021) by investigator assessment (INV) are reported. In 733 randomised patients (niraparib, 487; placebo, 246), median PFS follow-up was 3.5years. Median INV-PFS was 24.5 versus 11.2months (hazard ratio, 0.52; 95% confidence interval [CI], 0.40-0.68) in the HRd population and 13.8 versus 8.2months (hazard ratio, 0.66; 95% CI, 0.56-0.79) in the overall population for niraparib and placebo, respectively. In the HRp population, median INV-PFS was 8.4 versus 5.4months (hazard ratio, 0.65; 95% CI, 0.49-0.87), respectively. Results were concordant with the primary analysis. Niraparib-treated patients were more likely to be free of progression or death at 4years than placebo-treated patients (HRd, 38% versus 17%; overall, 24% versus 14%). The most common grade ≥ 3 treatment-emergent adverse events in niraparib patients were thrombocytopenia (39.7%), anaemia (31.6%), and neutropenia (21.3%). Myelodysplastic syndromes/acute myeloid leukaemia incidence rate (1.2%) was the same for niraparib- and placebo-treated patients. Overall survival remained immature. Niraparib maintained clinically significant improvements in PFS with 3.5years of follow-up in patients with newly diagnosed advanced ovarian cancer at high risk of progression irrespective of HRD status. No new safety signals were identified.

First-line lenvatinib plus pembrolizumab versus chemotherapy for advanced endometrial cancer: 1-Year follow-up after final analysis of the ENGOT-en9/LEAP-001 phase 3 trial

The phase 3 ENGOT-en9/LEAP-001 trial (NCT03884101) comparing first-line lenvatinib+pembrolizumab with carboplatin+paclitaxel did not meet pre-specified statistical criteria for overall survival or progression-free survival in participants with advanced/recurrent endometrial cancer. We report results after an additional year of follow-up (overall median 54.5 [range; 46.5-69.0] months). Eligible participants were adult females with stage III to IV or recurrent, histologically confirmed endometrial cancer. Measurable or non-measurable disease per Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1 and radiographically apparent disease per blinded independent central review was required. Participants were randomly allocated 1:1 to lenvatinib+pembrolizumab or chemotherapy (paclitaxel+carboplatin). The primary end points were overall survival and progression-free survival per RECIST version 1.1 by blinded independent central review. Secondary end points included objective response rate per RECIST version 1.1 by blinded independent central review and safety. The median overall survival (95% confidence interval [CI]) was 30.9 (range; 25.4-37.6) months with lenvatinib+pembrolizumab versus 29.4 (range; 26.2-34.8) months with chemotherapy in mismatch repair-proficient endometrial cancer (hazard ratio [HR] 0.99, 95% CI 0.82 to 1.21), 37.9 (range; 32.2-43.0) versus 32.3 (range; 27.2-35.7) months in all-comers (HR 0.91, 95% CI 0.77 to 1.09), and not reached in either treatment group in mismatch repair-deficient endometrial cancer (HR 0.60, 95% CI 0.39 to 0.93]). Corresponding results for progression-free survival were 9.6 (range; 8.2-11.9) versus 10.2 (range; 8.4-10.5) months (HR 1.01, 95% CI 0.83 to 1.22), 12.5 (range; 10.3-15.1) versus 10.2 (range; 8.4-10.4) months (HR 0.92, 95% CI 0.77 to 1.10]), and 31.8 (22.5 to not reached) versus 9.0 (range; 8.2-17.1) months (HR 0.62, 95% CI 0.41-0.93). Objective response rates were 50.6% versus 54.7%, 55.7% versus 55.5%, and 72.0% versus 58.0%, respectively. No new safety signals were identified. The results were consistent with those at the final analysis. The mismatch repair-proficient, all-comer, and mismatch repair-deficient populations continued to demonstrate antitumor activity for lenvatinib+pembrolizumab after an additional year of follow-up. These results should be interpreted with caution due to the exploratory nature of the analysis. ClinicalTrials.gov No. NCT03884101.

First-Line Lenvatinib Plus Pembrolizumab Versus Chemotherapy for Advanced Endometrial Cancer: A Randomized, Open-Label, Phase III Trial

PURPOSE Lenvatinib plus pembrolizumab (len + pembro) significantly improved progression-free survival (PFS) and overall survival (OS) versus chemotherapy in previously treated advanced or recurrent endometrial cancer (aEC) in the phase III Study 309/KEYNOTE-775. We report results from the phase III, randomized, open-label European Network of Gynaecological Oncological Trial-en9/LEAP-001 study (ClinicalTrials.gov identifier: NCT03884101 ) that evaluated len + pembro versus chemotherapy in first-line aEC. METHODS Patients with stage III to IV or recurrent, radiographically apparent EC and no previous chemotherapy or disease progression ≥6 months after neo/adjuvant platinum-based chemotherapy were randomly assigned 1:1 to lenvatinib 20 mg once daily plus pembrolizumab 200 mg once every 3 weeks or paclitaxel 175 mg/m 2 plus carboplatin AUC 6 mg/mL/min once every 3 weeks. Primary end points were PFS and OS, evaluated in the mismatch repair-proficient (pMMR) and all-comers populations. Noninferiority was assessed for OS at final analysis (FA) for len + pembro versus chemotherapy (multiplicity-adjusted, one-sided nominal alpha, .0159; null hypothesis–tested hazard ratio [HR], 1.1). RESULTS Eight hundred forty-two patients were randomly assigned (len + pembro, n = 420 [pMMR population, n = 320]; chemotherapy, n = 422 [pMMR population, n = 322]). At FA (data cutoff, October 2, 2023), median PFS (95% CI) in the pMMR population was 9.6 (8.2 to 11.9) versus 10.2 (8.4 to 10.5) months with len + pembro versus chemotherapy (hazard ratio [HR], 0.99 [95% CI, 0.82 to 1.21]) and among all-comers was 12.5 (10.3 to 15.1) versus 10.2 (8.4 to 10.4) months (HR, 0.91 [95% CI, 0.76 to 1.09]; descriptive analyses). Median OS (95% CI) in the pMMR population was 30.9 (25.4 to 37.7) versus 29.4 (26.2 to 35.4) months with len + pembro versus chemotherapy (HR, 1.02 [95% CI, 0.83 to 1.26]; noninferiority P = .246, not statistically significant per multiplicity control strategy) and among all-comers was 37.7 (32.2 to 43.6) versus 32.1 (27.2 to 35.7) months (HR, 0.93 [95% CI, 0.77 to 1.12]). Grade ≥3 treatment-related adverse events occurred in 331/420 (79%) versus 274/411 (67%) treated patients. CONCLUSION First-line len + pembro did not meet prespecified statistical criteria for PFS or OS versus chemotherapy in pMMR aEC.

Pembrolizumab or Placebo Plus Adjuvant Chemotherapy With or Without Radiotherapy for Newly Diagnosed, High-Risk Endometrial Cancer: Results in Mismatch Repair-Deficient Tumors

Mismatch repair-deficient (dMMR) endometrial cancer (EC) is an inflamed phenotype with poor outcomes when meeting high-risk criteria and limited treatment options in the adjuvant setting. We report protocol-prespecified subgroup analysis of patients with dMMR tumors from the phase III ENGOT-en11/GOG-3053/KEYNOTE-B21 study (ClinicalTrials.gov identifier: NCT04634877 ) in newly diagnosed, high-risk EC after surgery with curative intent. Patients were randomly assigned to pembrolizumab 200 mg or placebo (six cycles) plus carboplatin-paclitaxel (four to six cycles) once every 3 weeks, then pembrolizumab 400 mg or placebo once every 6 weeks (six cycles), respectively. MMR status was a stratification factor. Patients received radiotherapy at investigator discretion. Investigator-assessed disease-free survival (DFS) was a primary end point. No formal hypothesis testing was performed for subgroup analysis. In the intention-to-treat population, 141 patients in the pembrolizumab arm and 140 in the placebo arm had dMMR tumors. At this interim analysis, hazard ratio for DFS favored pembrolizumab (0.31 [95% CI, 0.14 to 0.69]); median DFS was not reached in either group. Two-year DFS rates were 92.4% (95% CI, 84.4 to 96.4) and 80.2% (95% CI, 70.8 to 86.9), respectively. No new safety signals occurred. Longer-term follow-up of outcomes will be evaluated at final analysis. Preplanned subgroup analysis on the basis of the study's stratification factors suggests that pembrolizumab plus chemotherapy improves DFS and is clinically relevant for patients with dMMR tumors in the curative-intent setting.

A Study of Niraparib (GSK3985771) Maintenance Treatment in Participants With Advanced Ovarian Cancer Following Response on Front-Line Platinum-Based Chemotherapy

This study aims to assess efficacy of Niraparib (GSK3985771) as maintenance treatment in participants with Stage III or IV ovarian cancer. Participants must have completed front-line platinum based regimen with complete response (CR) or partial response (PR). Data collection for Secondary Outcome measures is ongoing and the approximate duration of the study will be 7 years.