A phase 2 trial found neoadjuvant olaparib followed by cytoreductive surgery was feasible and safe, and postoperative olaparib alone was as effective as chemotherapy followed by olaparib and less toxic among patients with platinum-sensitive, high-grade serous ovarian cancer.

These data will be presented by Stephanie Lheureux, MD, Princess Margaret Cancer Centre, Toronto, Ontario, Canada, at the 2024 American Society of Clinical Oncology (ASCO) Annual Meeting in Chicago, Illinois.

This randomized, open-label study enrolled 44 PARP-naïve patients with recurrent high-grade serous ovarian cancer at ≥6 months following previous platinum therapy. All patients were suitable for secondary cytoreductive surgery and underwent neoadjuvant therapy with 300mg oral olaparib twice daily for 4 to 8 weeks. Following surgery, patients were randomized on a 1-to-1 basis to receive either 6 cycles of platinum chemotherapy followed by maintenance olaparib or olaparib alone. The primary end point was progression-free survival with overall survival as a secondary end point.

Of the 44 patients enrolled, 36 were randomized (olaparib plus chemotherapy arm, n = 19; olaparib alone arm, n = 17). Of the 36 patients who underwent surgery, 31 had no visible residual disease following cytoreduction. There were 6 patients assigned to the olaparib plus chemotherapy arm due to disease progression during the neoadjuvant olaparib treatment. The 3-year PFS and OS rates were the same, at 84.2% in the olaparib plus chemotherapy arm vs 75.1% in the olaparib along arm (HR, 0.90). There was no difference observed in either PFS or OS between the 2 arms (P = .85). Patients with no visible residual disease had a better OS (HR, 0.23; P = .0097).

There were no cases of myelodysplastic syndrome or acute myeloid leukemia reported. No grade >3 adverse events were reported during the neoadjuvant therapy. During the first 6 months of adjuvant therapy, grade >3 adverse events occurred in 16% of patients in the olaparib plus chemotherapy arm vs 4% in the olaparib alone arm.

Study authors concluded, for patients with resectable disease at secondary cytoreduction, perioperative olaparib may represent “a chemo-free approach in this selected population.”

Source:

Lheureux S, May T, Wilson MK, et al. Phase II randomized multi-centre study of neoadjuvant olaparib in patients with platinum sensitive relapsed high-grade serous ovarian cancer: The NEO trial. Presented at the ASCO Annual Meeting. May 31 – June 4, 2024; Chicago, IL. Abstract #5506