SOLO-2: Overall Survival Data on Olaparib for Relapsed, BRCA-Mutated Ovarian Cancer

May 29, 2020

SOLO-2 is the first phase 3 trial to provide overall survival (OS) data on maintenance PARP inhibitor therapy.

An abstract presented in the 2020 American Society of Clinical Oncology (ASCO) Virtual Scientific Program reported that treatment with olaparib (Lynparza) extended overall survival (OS) in patients with platinum-sensitive, relapsed ovarian cancer (PSROC) and a BRCA mutation.1

Olaparib is a poly ADP ribose polymerase (PARP) inhibitor that has been approved for maintenance therapy in patients with PSROC, regardless of BRCA mutation status, in many countries.1

“This study confirms that the PARP inhibitor olaparib should be the standard maintenance therapy for patients with BRCA-related relapsed ovarian cancer responding to platinum-based chemotherapy – a significant advance for women with a cancer that has a historically poor prognosis,” said ASCO Chief Medical Officer and Executive Vice President Richard L. Schilsky, MD, FASP, FSCT, FASCO.2

The phase 3, randomized, SOLO2 trial incorporated 295 patients with relapsed, high-grade ovarian cancer (including primary peritoneal of fallopian tube cancer) or endometrioid cancer, with a BRCA mutation,  who received at least 2 lines of chemotherapy and were responding to platinum-based chemotherapy. Participants were randomized to receive either 300 mg of olaparib or placebo; 196 received olaparib, whereas 99 received placebo. The study continued until disease progression occurred. Previous results from the SOLO2 trial found that maintenance olaparib tablets resulted in median progression free survival (PFS) improvement of 13.6 months over the placebo group.1

Overall, the OS analysis showed that olaparib extended OS by approximately 12.9 months compared with placebo. After a median follow-up of 65 months in both treatment arms, 28.3% of patients who received olaparib were alive and had not received subsequent treatment, compared with 12.8% of patients who receive a placebo. At 5 years follow up, 42.1% of women on olaparib were alive, compared with 33.2% on placebo. Patients who recieved olaparib in the time between disease response and progression had a 26% reduced risk of death, according to the findings.1 Overall, 38.4% of patients in the placebo group crossed over to treatment with olaparib.

The most frequent treatment emergent adverse events were nausea, fatigue/asthenia, and anemia; olaparib tablets had a manageable tolerability profile, according to the investigators.1

“A median overall survival improvement of nearly 13 months is impressive in ovarian cancer and brings a substantial benefit to our patients,” said lead author Andres Poveda, MD, of Initia Oncology, Hospital Quironsalud, in Valencia, Spain. “With the addition of overall survival data, this study helps usher in a new era of personalized medicine for women with this difficult-to-treat cancer.”2

This study was funded by AstraZeneca and Merck Sharp & Dohme Corp.2

References:

1. Poveda A, Floquet A, Ledermann J, et al. Final overall survival results from SOLO2/ENGOT-ov21: a phase III trial assessing survival after maintenance treatment with the PARP inhibitor olaparib in patients with platinum-sensitive, relapsed ovarian cancer and a BRCA mutation. Presented at: 2020 American Society of Clinical Oncology Virtual Scientific Program; May 29-31; online.
2. Maintenance Therapy With PARP Inhibitor Olaparib Extends Survival By Over 1 Year in Patients With Relapsed Ovarian Cancer and BRCA Mutation. News Release. ASCO; May 13, 2020. Accessed May 13, 2020.  https://www.asco.org/about-asco/press-center/news-releases/maintenance-therapy-parp-inhibitor-olaparib-extends-survival