Atezolizumab plus chemotherapy and maintenance niraparib in late-relapsing recurrent chemotherapy-sensitive ovarian cancer does not significantly improve outcomes.

Standard therapy for ovarian cancer with a treatment-free interval of more than 6 months (late-relapsing) is chemotherapy, followed by PARP-inhibitor maintenance if a response to chemotherapy is observed. Despite a strong preclinical rationale, most previous phase 3 studies failed to show the benefit of the addition of a PD-L1 inhibitor to this standard treatment.^1-4

The phase 3 ANITA trial (NCT03598270) evaluated the effectiveness of the PD-1 checkpoint inhibitor atezolizumab in participants treated with chemotherapy and subsequent maintenance PARP inhibition. ANITA enrolled 417 participants with high-grade late-relapsing recurrent ovarian cancer who were randomized 1:1 to 6 cycles of chemotherapy with or without atezolizumab, followed by maintenance niraparib with or without atezolizumab in case of chemotherapy sensitivity. The primary endpoint was PFS. Dr. Antonio Gonzalez Martin of the Cancer Center Clinica Universidad de Navarre, Spain, presented the first results of the study.⁵

The addition of atezolizumab did not significantly improve median PFS: 11.2 months versus 10.2 months (HR, 0.89; 95% CI, 0.71-1.10; P=.28). No benefit of atezolizumab was observed in all prespecified subgroups, including PD-L1 status. Also, atezolizumab did not improve ORR (45% vs 43%) or any other secondary endpoint available at this point.

Placing these results in the context of other studies on this subject, discussant Dr. Charlie Gourley of the University of Edinburgh suggested that the (negative) results of ANITA fit the idea that bevacizumab is required to “unlock” the synergy of the PARP inhibitor and immune checkpoint inhibitor combination. The role of bevacizumab in the treatment of this ovarian cancer setting, however, is not clear.⁶ Yet, in both the DUO-O (NCT03737643) and MEDIOLA trials (NCT02734004), triplet therapy (PARP inhibitor, immune checkpoint inhibitor, bevacizumab) showed benefit in ORR or PFS over doublet therapy.^6,7

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