Atezolizumab Plus Chemotherapy Improved Progression-Free Survival Among Patients With Advanced or Recurrent Endometrial Cancer

Interim Analysis of the Phase 3 AtTEnd Trial 

Interim analysis results from the phase 3 AtTEnd trial demonstrated that atezolizumab plus chemotherapy improved progression-free survival (PFS) among patients with advanced or recurrent endometrial cancer. 

“Standard treatment for advanced or recurrent endometrial cancer included carboplatin and paclitaxel chemotherapy,” stated Professor Nicoletta Colombo, University of Milan-Bicocca, Milan, Italy, and coauthors. “This trial assessed whether combining atezolizumab with chemotherapy might improve outcomes in this population.” 

This double-blind, placebo-controlled trial enrolled 551 patients with advanced or recurrent endometrial carcinoma or carcinosarcoma who received no prior systemic chemotherapy for recurrence. Patients were randomized on a 2-to-1 basis to receive chemotherapy (carboplatin AUC 5 or 6 and paclitaxel 175 mg/m2 intravenously on day 1 every 21 days) plus either 1200 mg of atezolizumab (n = 362) or placebo (n = 189) for 6 to 8 cycles, continued until disease progression. Stratification was based on country, histological subtype, advanced or recurrent status, and deficient mismatch repair (dMMR) status. Co-primary end points included PFS, in both the intention-to-treat population and among patients with dMMR tumors (n = 125), and overall survival (OS) in the intention-to-treat population. A key secondary end point was safety. 

At a median follow-up of 28.3 months, the median PFS in the dMMR cohort was not estimable in the atezolizumab arm and 6.9 months in the placebo arm (hazard ratio [HR] 0.36; 95% confidence interval [CI], 0.23 to 0.57; P = .0005). In the intention-to-treat population, median PFS was 10.1 months in the atezolizumab arm and 8.9 months in the placebo arm (HR 0.74; 95% CI, 0.61 to 0.91; P = .022). Median OS was 38.7 months in the atezolizumab arm and 30.2 months in the placebo arm (HR 0.82; 95% CI, 0.63 to 1.07; P = .048). The most common grade 3/4 adverse events included neutropenia and anemia. Serious treatment-related adverse events were reported in 13% of patients in the atezolizumab arm and 3% of patients in the placebo arm. Two treatment-related deaths occurred due to pneumonia. 

As Dr Colombo et al concluded, “Atezolizumab plus chemotherapy increased progression-free survival in patients with advanced or recurrent endometrial carcinoma, particularly in those with dMMR carcinomas, suggesting the addition of atezolizumab to standard chemotherapy as first-line treatment in this specific subgroup.”

Source: 

Colombo N, Biagioli E, Harano K, et al. Atezolizumab and chemotherapy for advanced or recurrent endometrial cancer (AtTEnd): A randomised, double-blind, placebo-controlled, phase 3 trial. Lancet Oncol. Published online: August 2, 2024. doi: 10.1016/S1470-2045(24)00334-6