Real-World-Data (Rwd) On Platinum (Pt) Outcomes After Parp Inhibitors (Parpi) Progression In High Grade Serous Ovarian Cancer (Hgsoc) Patients (P)

PARPi maintenance after Pt-based chemotherapy (CT) significantly improves progression-free survival (PFS) and PFS to subsequent (ssq) chemotherapy (PFS2) in relapsed HGSOC. However, crossed mechanisms of action and resistance between PARPi and Pt cast doubts on the benefit from ssq Pt after PARPi progression. We provide RWD on this issue. We included HGSOC p treated with ssq CT after progression to maintenance PARPi until 31st Dec 2019 in 3 large hospitals. Endpoints were overall response rate (ORR), median (m) PFS and overall survival (mOS) to ssq Pt after PARPi. Analysis were also performed according to 3 populations: p who received ssq non-Pt CT, p with Pt-free interval (PFI) 6-12 months (mo) and p with PFI >12 mo. 54 p were identified (57.4 % BRCAmut). 4p (7.4%) received PARPi after 1st line CT, 25 (46.3%) after 2nd line, and 25 (46.3%) after ≥3rd line. 34p (63%) received olaparib and 20 (37%) niraparib. mPFS of PARPi as maintenance in the recurrent setting was 7.5 mo and PFS2 15.4 mo. Distribution of ssq CT schemes and their best responses are shown in the table. ORR to ssq Pt was 33.3%, and progression disease (PD) 28.6%. ORR in p who received ssq Pt-free CT, p with PFI 6-12 mo, and p with PFI >12 mo were 28.6%, 22.7% and 45%, respectively. The 4 identified complete responses (CR) occurred among BRCAmut p receiving PARPi in the recurrent setting and PFI>12. Survival endpoints of ssq CT are shown in the table. mPFS and mOS were significantly longer in the PFI >12 subgroup versus the others. Survival did not change when excluding the 4p who received PARPi as 1st line (Table).Table:Non Pt-CTN=9Pt-CTpPFI 6-12 mo N=24PFI >12 mo N=21BRCAmut (n, %)5 (55.6)12 (50)14 (66.7)0.055From ssq CT after PARPi:Best responses (n, %)*0.010CR004 (20)Partial response2 (28.6)5 (22.7)5 (25)Stable disease2 (28.6)6 (27.3)10 (50)PD3 (42.9)11 (50.0)1 (5)mPFS (mo, 95%CI)5.1(3.2-)5.1 (4.0-9.0)9.4 (6.7-14.0)0.055mOS (mo, 95%CI)6.8 (3.12-)14.2 (9.4-)28.2 (11.9-)0.018*Evaluable p (n=49). Open table in a new tab *Evaluable p (n=49). Higher benefit from ssq Pt after PARPi was observed in the PFI>12 subgroup. Benefit from ssq Pt after PARPi in the PFI 6-12 subgroup was similar to benefit from CT in the non-Pt subgroup. The role of ssq Pt after PARPi in the PFI 6-12 subgroup warrants further research.