According to primary analysis results from the phase 3 ENGOT-Ov41/GEICO 69-O/ANITA study, the addition of atezolizumab to carboplatin doublet chemotherapy and maintenance niraparib did not significantly improve progression-free survival (PFS) or objective response rate (ORR) among patients with late-relapsing recurrent ovarian cancer. 

These results were presented at the 2023 European Society for Medical Oncology Congress in Madrid, Spain, by lead author, Antonio Gonzalez Martin, MD, PhD, Cancer Center Clínica Universidad de Navarra, Madrid, Spain. 

“Standard therapy for late-relapsing [recurrent ovarian cancer] includes PARPi maintenance if disease responds to platinum-based [chemotherapy],” stated Dr Gonzalez Martin and coauthors. “ANITA is the first-reported phase 3 trial evaluating [atezolizumab] with platinum-based [chemotherapy] and maintenance PARPi in late-relapsing [recurrent ovarian cancer].”

In this double-blind, placebo-controlled study, 417 patients with measurable high-grade serous, endometrioid, or undifferentiated recurrent ovarian cancer who received ≤2 prior lines of chemotherapy and had a platinum therapy-free interval (TFIp) of >6 months were enrolled. Patients previously treated with either a PARP inhibitor (PARPi) or an immune checkpoint inhibitor for recurrent ovarian cancer were excluded. 

Patients were randomized on a 1-to-1 basis to receive a carboplatin doublet (investigator’s choice paclitaxel, gemcitabine, or pegylated liposomal doxorubicin) for 6 cycles followed by maintenance niraparib at an individualized starting dose followed by either atezolizumab (1200 mg every 3 weeks or 840 mg every 2 weeks; dependent upon chemotherapy regimen) or placebo until disease progression. Stratification was based on carboplatin doublet, TFIP (6 to 12 months vs >12 months), BRCA-status, and PD-L1 status (PD-L1-expressing immune cells on <1% vs ≥1% tumor area vs non-informative by SP142). The primary end point was investigator-assessed PFS.

At a median follow-up of 36 months, 209 patients have been treated in the placebo arm and 208 patients had been treated in the atezolizumab arm. Events occurred in 174 patients in the placebo arm and 170 patients in the atezolizumab arm (hazard ratio [HR], 0.89; 95% confidence interval [CI], 0.71 to 1.10; P = 0.28). Median PFS was 10.1 months in the placebo arm and 11.2 months in the atezolizumab arm. Overall response to chemotherapy was 43% and 45% in the placebo and atezolizumab arms respectively. The safety profile was consistent with that of previous studies. 

“Combining [atezolizumab] with [chemotherapy] and maintenance niraparib for late-relapsing [recurrent ovarian cancer] did not significantly improve PFS or ORR,” concluded Dr Gonzalez Martin and coauthors. 

Source: 

Gonzalez Martin A, Rubio Perez MJ, Heitz F, et al. Atezolizumab (atezo) combined with platinum-based chemotherapy (CT) and maintenance niraparib for recurrent ovarian cancer (rOC) with a platinum-free interval (TFIp) >6 months: Primary analysis of the double-blind placebo (pbo)-controlled ENGOT-Ov41/GEICO 69-O/ANITA phase III trial. Presented at the 2023 ESMO Congress; October 20-24, 2023; Madrid, Spain. Abstract LBA37