Olaparib maintenance is generally well tolerated by patients with newly diagnosed, BRCA-mutated, advanced ovarian cancer, according to updated data from the SOLO1 trial published in Gynecologic Oncology.

The phase 3 SOLO1 trial (ClinicalTrials.gov Identifier: NCT01844986) enrolled 391 patients with newly diagnosed, BRCA-mutated, advanced ovarian cancer who responded to first-line platinum-based chemotherapy.

Patients were randomly assigned 2:1 to receive maintenance with olaparib (260 patients) or placebo (131 patients, 130 evaluable for safety). The median treatment duration was 24.6 months with olaparib and 13.9 months with placebo. 


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In the primary analysis, olaparib was associated with a 70% reduction in the risk of disease progression or death (hazard ratio, 0.30; 95% CI, 0.23-0.41; P <.001).2 Updated results showed a 5-year progression-free survival rate of 48.3% in the olaparib arm and 20.5% in the placebo arm.3

For the current analysis, investigators reported data on the safety and tolerability of olaparib maintenance.1

The incidence of adverse events (AEs) up to 30 days after the end of treatment was 98.5% in the olaparib arm and 92.3% in the placebo arm. The incidence of serious AEs was 20.8% and 12.3%, respectively.

Among patients treated with olaparib, the most common hematologic AEs were anemia (38.8%), neutropenia (23.1%), and thrombocytopenia (11.2%). The median time to first onset of these AEs was 1.94 months, 1.77 months, and 2.83 months, respectively.

Nausea (77.3%), fatigue/asthenia (63.5%), and vomiting (40.0%) were the most common non-hematologic AEs in the olaparib arm. The median time to first onset of these AEs was 0.13 months, 0.72 months, and 1.46 months, respectively.

The first event of anemia, thrombocytopenia, neutropenia, nausea, or vomiting lasted a median of less than 2 months, but the first event of fatigue/asthenia lasted a median of 3.48 months.

Most AEs in the olaparib arm were manageable with supportive treatment or dose modifications, the study authors noted. 

Of the 162 patients still receiving olaparib at month 24, 64.2% were receiving the recommended dose (300 mg twice daily), and 17% were receiving a reduced dose (250 mg twice daily). 

With a median follow-up of 58.1 months for olaparib and 59.6 months for placebo, there were no new cases of myelodysplastic syndromes or acute myeloid leukemia in either treatment arm.

The study authors concluded that olaparib maintenance is associated with manageable toxicity, and no new safety signals were identified with extended follow-up.

Disclosures: This research was supported by AstraZeneca and is part of an alliance between AstraZeneca and Merck Sharp & Dohme Corp. Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of disclosures.

References

  1. Colombo N, Moore K, Scambia G, et al. Tolerability of maintenance olaparib in newly diagnosed patients with advanced ovarian cancer and a BRCA mutation in the randomized phase III SOLO1 trial. Gynecol Oncol. Published August 2, 2021. doi: 10.1016/j.ygyno.2021.07.016
  2. Moore K, Colombo N, Scambia G, et al. Maintenance olaparib in patients with newly diagnosed advanced ovarian cancer. N Engl J Med. 2018;379(26):2495-2505.
  3. doi:10.1056/NEJMoa1810858
  4. Banerjee S, Moore KN, Colombo N, et al. Maintenance olaparib for patients (pts) with newly diagnosed, advanced ovarian cancer (OC) and a BRCA mutation (BRCAm): 5-year (y) follow-up (f/u) from SOLO1. Ann Oncol. 2020;31(Suppl 4). Abstract 811MO.

This article originally appeared on Cancer Therapy Advisor