Association between homologous recombination deficiency and time to treatment failure to platinum-based chemotherapy for pancreatic cancer by using the C-CAT database.

BACKGROUND

Since homologous recombination deficiency (HRD) is relatively uncommon in pancreatic cancer (PC), its impact on time-to-treatment failure (TTF) among patients undergoing systemic chemotherapy for unresectable and recurrent PC remains uncertain.

METHODS

Among patients with unresectable and recurrent PC enrolled in the Center for Cancer Genomics and Advanced Therapeutics (C-CAT) database by July 2023, a total of 1394 patients who underwent first-line chemotherapy with either gemcitabine plus nab-paclitaxel (GnP) or FOLFIRINOX (FFX) and received tissue-based CGP tests after disease progression were included in this study. HRD was defined as the presence of germline or somatic genetic mutations in homologous recombination repair (HRR)-related genes such as ATM, BARD1, BRIP1, BRCA1/2, CHEK2, CDK12, PALB, and RAD51C/D. We investigated the correlation between HRD and TTF among patients treated with GnP and FFX.

RESULTS

First-line chemotherapy consisted of GnP in 69% of the cases and FFX in 31%. The CGP tests used were NCC OncoPanel and FoundationOne CDx in 26% and 74%, respectively. HRR-related genetic abnormalities were identified in 107 patients (7.6%): BRCA2 (n = 51), ATM (n = 34), BRCA1 (n = 9), PALB2 (n = 9), among others. In the GnP cohort, the median TTF was comparable between the HRD and non-HRD groups (5.3 vs 4.6 months, P = 0.44). Conversely, in the FFX cohort, it was significantly longer in the HRD group compared to the non-HRD group (7.3 vs. 4.7 months, p < 0.01).

CONCLUSIONS

Our findings suggest that HRR-related genetic abnormalities might be predictive of TTF in platinum-based chemotherapy for PC.