Patients with BRCA-mutated, advanced ovarian cancer who respond to first-line therapy continue to have clinical benefits from olaparib maintenance therapy beyond the 2-year treatment cap, according to research presented at ESMO Congress 2022.1
An update of the SOLO1 trial showed a clinically meaningful, but not statistically significant, improvement in overall survival (OS) with olaparib vs placebo at 7 years of follow-up, according to study presenter Paul DiSilvestro, MD, of Women & Infants Hospital in Providence, Rhode Island.
These results support the use of olaparib maintenance in these patients to achieve long-term remission and possibly enhance the potential for cure, Dr DiSilvestro said.
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The SOLO1/GOG-3004 trial (ClinicalTrials.gov Identifier: NCT01844986) recruited 391 patients with stage III-IV, BRCA-mutated ovarian, primary peritoneal, or fallopian tube cancer. Patients had responded to first-line platinum-based chemotherapy and were randomly assigned to receive 300 mg of olaparib maintenance therapy twice daily (n=260) or placebo (n=131) for 2 years or until disease progression.
Baseline characteristics were well balanced between the arms. Most patients had stage III disease (84.6% in the olaparib arm and 80.2% in the placebo arm), BRCA1 mutations (73.5% and 69.5%, respectively), a history of upfront cytoreductive surgery (61.9% vs 64.9%), and achieved a complete response after surgery/chemotherapy (81.9% vs 81.7%).
The median duration of maintenance was 24.6 months in the olaparib arm and 13.9 months in the placebo arm. The median follow-up was 88.9 months and 87.4 months, respectively.
At 7 years, the OS rate was 67.0% in the olaparib arm and 46.5% in the placebo arm. The median OS was not reached in the olaparib arm and was 75.2 months in the placebo arm (hazard ratio [HR], 0.55; 95% CI, 0.40-0.76; P =.0004). This did not reach the prespecified threshold for statistical significance, which was P <.0001.
Dr DiSilvestro noted that 44.3% of the placebo recipients and 14.6% of the olaparib recipients went on to receive subsequent PARP inhibitor therapy.
The median time to first subsequent therapy was 64.0 months for the olaparib arm and 15.1 months for the control arm (HR, 0.37; 95% CI, 0.28-0.48). The median time to second subsequent therapy was 93.2 months and 40.7 months, respectively (HR, 0.50; 95% CI, 0.37-0.67).
No additional safety signals were observed in this analysis. The most common adverse events of special interest (in the olaparib and placebo arms, respectively) were new primary malignancies (5.4% vs 6.2%), myelodysplastic syndrome or acute myeloid leukemia (1.5% vs 0.8%), and pneumonitis/interstitial lung disease (1.9% vs 0%).
These findings were published in the Journal of Clinical Oncology in parallel with this presentation.2
Disclosures: This study was supported by AstraZeneca as part of an alliance between AstraZeneca and Merck Sharp & Dohme LLC. Some of the study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original references for a full list of disclosures.
References
- DiSilvestro P, Banerjee S, Colombo N, et al. Overall survival (OS) at 7-year (y) follow-up (f/u) in patients (pts) with newly diagnosed advanced ovarian cancer (OC) and a BRCA mutation (BRCAm) who received maintenance olaparib in the SOLO1/GOG-3004 trial. Presented at ESMO 2022; September 9-13, 2022. Abstract 517O.
- DiSilvestro P, Banerjee S, Colombo N, et al. Overall survival with maintenance olaparib at a 7-year follow-up in patients with newly diagnosed advanced ovarian cancer and a BRCA mutation: The SOLO1/GOG 3004 trial. J Clin Oncol. Published online September 9, 2022. doi:10.1200/JCO.22.01549
