Multi-gene assays often include UGT1A1 and, in certain instances, may report associated toxicity risks for irinotecan, belinostat, pazopanib, and nilotinib. However, guidance for incorporating UGT1A1 results into therapeutic decision-making is mostly lacking for these anticancer drugs. We summarized meta-analyses, genome-wide association studies, clinical trials, drug labels, and guidelines relating to the impact of UGT1A1 polymorphisms on irinotecan, belinostat, pazopanib, or nilotinib toxicities. For irinotecan, UGT1A1*28 was significantly associated with neutropenia and diarrhea, particularly with doses ≥ 180 mg/m², supporting the use of UGT1A1 to guide irinotecan prescribing. The drug label for belinostat recommends a reduced starting dose of 750 mg/m² for UGT1A1*28 homozygotes, though published studies supporting this recommendation are sparse. There was a correlation between UGT1A1 polymorphisms and pazopanib-induced hepatotoxicity, though further studies are needed to elucidate the role of UGT1A1-guided pazopanib dose adjustments. Limited studies have investigated the association between UGT1A1 polymorphisms and nilotinib-induced hepatotoxicity, with data currently insufficient for UGT1A1-guided nilotinib dose adjustments.

Background: Limited data are available regarding the anticancer activity of PARP inhibitors (PARPis) in pancreatic cancer with mutations in HRR genes other than BRCA and PALB2. Methods: We retrospectively reviewed the clinical characteristics and outcomes of 48 patients with advanced pancreatic cancer harboring pathogenic germline and/or somatic HRR mutations who were treated with PARPis. Results: Thirty patients had germline (g)HRR mutations only, twelve had somatic (s)HRR mutations only, and six had concomitant gHRR and sHRR mutations. The objective response rate (ORR) was 22%. The median progression-free survival (mPFS) and overall survival (mOS) were 6.9 and 11.5 months, respectively. Five patients received olaparib in the front-line setting due to borderline performance status. Their ORR was 20%, and their mPFS and mOS were both 11.3 months. The ORR was higher in patients with BRCA or PALB2 mutations (germline or somatic) than in those with non-BRCA/PALB2 mutations. Patients with somatic non-BRCA/PALB2 variants had a shorter mPFS. Patients with concomitant gHRR/sHRR mutations or gHRR mutations alone had a significantly longer mPFS than those with sHRR mutations only. Conclusions: PARP inhibitors may be considered for patients with advanced pancreatic cancer harboring pathogenic alterations of BRCA who cannot tolerate standard chemotherapy. Maintenance PARPis can be considered in selected patients with non-BRCA/non-PALB2 HRR mutations.