The impact of HRD mutation on survival in patients with KRAS-mutated advanced pancreatic cancer: A real-world database study.

221 Background: Advanced pancreatic ductal adenocarcinoma (PDAC) is associated with a poor prognosis. Prior studies indicate that homologous repair deficient (HRD+ve) PDAC patients (pts) have improved survival and greater response to platinum agents, but the optimal treatment for these population is still unclear. Here, we evaluate the survival impact of HRD mutations in KRAS-mutated PDAC, which represent 90% of cases, in a real-world setting. Methods: We retrospectively reviewed all pts diagnosed with KRAS-mutated PDAC from Jun 2019 to Dec 2021, who were registered in the Center for Cancer Genomics and Advanced Therapeutics (C-CAT), the cancer registry with comprehensive genomic profiling (CGP) data. Pts were stratified with the presence or absence of HRD mutations identified through Foundation One, including ATM, ATR, BRCA1, BRCA2, BRIP1, CHEK2, FANCA, PALB2, and RAD51. We analyzed the prevalence of co-alterations and the impact of HRD status on survival. Pts with a history of systemic therapy for curative intent were excluded from the survival analysis. Results: In 2251 PDAC cases (HRD+ve 232pts, HRD-ve 2019pts) enrolled, we found that HRD+ve PDAC had a significantly lower incidence of TP53 mutation (p<0.001), CDKN2A mutation (p<0.046), and CDKN2A loss (p<0.046). Survival analysis was performed in 823 pts (HRD+ve 92pts, HRD-ve 731pts). HRD+ve pts had significantly longer overall survival (OS, 28.8m vs 23.5m, P=0.030). In the first line setting, HRD+ve pts had exhibited a markedly extended time-to-treatment failure (TTF; HRD+ve, 19pts vs. HRD-ve, 177pts; 7.6m vs. 5.4m; p=0.026) and OS (HRD+ve, 30pts vs. HRD-ve, 239pts; 28.8m vs. 23.5m; p=0.019) when treated with mFOLFIRINOX (mFFX), but not when treated with gemcitabine plus nab-paclitaxel (GA; HRD+ve, 34pts vs. HRD-ve 276pts; OS, 29.3m vs 26.3m; p=0.34; TTF, 5.2m vs. 5.2m; p=0.80). In the second line setting, there were no differences in TTF between HRD+ve and HRD-ve irrespective of these regimens. Among HRD+ve PDAC pts, pts who having received mFFX tend to have better survival compared to those who did not (46pts vs. 46pts; OS, 31.7m vs 26.3m; p=0.09). Conclusions: Our analysis has identified a unique profile in HRD+ve PDAC, underscoring the importance of platinum-based chemotherapy in the initial treatment to enhance survival, which highlights the practical clinical benefits of routine CGP for pts with KRAS-mutated PDAC.