Introduction/Background Bevacizumab, in combination with chemotherapy for frontline therapy, remains a standard-of-care option for advanced ovarian cancer. We aimed to evaluate Bevacizumab in the first-line treatment of Ovarian Cancer (OC) and correlate it with the KELIM score (rate of elimination of Ca 125 constant K) in patients with high-grade serous ovarian cancer (HGSOC) undergoing neoadjuvant chemotherapy (NACT).

Methodology Retrospective study of OC patients treated with first-line Bevacizumab at the Royal Marsden Hospital (RMH) between February 2012 and June 2021.

Electronic records were reviewed to retrieve clinicopathological characteristics and surgical outcomes. The KELIM score was calculated using the biomarker kinetics online tool. SPSS was used for statistical analysis.

Results 185 patients were identified. The median age was 62 years (range 27–85). 17 patients (9.2%) had a germline BRCA mutation (gBRCAmut). 149 (80.5%) of patients had surgery: primary, interval, and delayed in 23.2%, 50.8%, and 6.5% of cases respectively. Bevacizumab was prescribed at 7.5 mg/kg and initiated with cycle 4–6 of chemotherapy in most cases (66.5%). Median platinum-free interval (mPFI) was 16 months (95% CI 13.4–18.8), median progression-free survival (mPFS) was 17 (95% CI 14.2–19.8) months, and median overall survival (mOS) 43.3 (95% CI 35.1–51.5) months in the overall population. In the gBRCAmut patients, mPFS was 21 vs 18 months for the BRCA wild-type population (p=0.005); and the mOS was 75.7 versus 44.1 months (p=0.01). In patients undergoing NACT (n=100), KELIM was assessable in 88 cases.

Optimal cytoreductive surgery was achieved in 40 patients with KELIM≥ 1 vs 25 patients with KELIM <1, mPFI (15 vs 6 m), mPFS (20 vs 12 m), and mOS (65.3 vs 31.8m) were longer with a KELIM ≥1.

Conclusion We report real-world outcomes of first-line Bevacizumab in advanced OC. The KELIM score can be a valuable tool to help predict platinum sensitivity and survival outcomes in patients with HGSOC undergoing NACT.

Disclosures NA.