42P Efficacy of maintenance with PARPi in advanced ovarian cancer according to the location of BRCA mutation

Currently little is known about correlations between the type and location of BReast CAncer genes (BRCA) 1/2 mutations response to Poly (ADP-ribose) polymerase inhibitors (PARPi) in ovarian cancer (OC). Clinical data from PAOLA1 study suggest that patients with DNA binding domain (DNA-BD) BRCA1 are more sensitive combination olaparib/bevacizumab those DNA-BD BRCA2 confer excellent outcomes. We investigated if BRCA related PARPi sensitivity. This multicenter retrospective evaluated efficacy according mutation functional (FD) (RING, or C terminus [BRCT]) (PALB2, RAD51-BD; DNA-BD). BRCA1/2 germline mutated OC receiving as maintenance, after a platinum-based first line chemotherapy were enrolled. Baseline characteristics survival collected 3 academic centers. Of 202 treated December 2008 October 2021, 122 (60.4%) received first-line setting 80 (39.6%) at recurrence. Among group, 73 (60%) 49 (40%) harbored mutations, respectively. FDs RING, BRCT found (2.5%), 8 (6.6%) 21 (17.2%) patients, detected RAD51-BD 25 (20.5%) 5 (4.1%) Median follow-up was 20 (4-100) months. In BRCA1/2, 2-yr Progression Free Survival PFS 100%, compared 80% other domains (log rank p= 0.079). With regard type, harboring missense had longer (2-yr 100%), 50% splicing 0.021) 75% nonsense 0.049). Mutation types not analyzed due small numbers. The results confirmed region respect mutation. Besides, has best prognosis,