Abstract P1-08-02: Cytochrome P450 reductase gene, POR, associated with paclitaxel induced peripheral neuropathy in patients of European ancestry from the adjuvant breast cancer trial, ECOG-ACRIN E5103

Abstract Introduction: Paclitaxel induced peripheral neuropathy (TIPN) is one of the most important survivorship issues of cancer patients with the potential to substantially impact quality of life. TIPN can lead to dose reductions, early cessation, and has the potential to compromise treatment efficacy. We previously reported both rare (SBF2) and common germline (FCAMR) predictors for TIPN in patients of African descent through whole-exome sequencing (WES) and a genome-wide association study (GWAS), respectively, in the adjuvant, randomized phase III breast cancer trial, E5103. These predictors are now being evaluated in the prospective ECOG-ACRIN trial EAZ171 (NCT04001829). We have also previously reported our evaluation of common germline variants for patients of European descent through GWAS in E5103 with validation in another adjuvant breast cancer trial, E1199. Herein, we evaluated for rare variants that were associated with risk of TIPN in patients of European ancestry from WES in E5103. Methods: Gene-based rare variant analyses using SKAT were performed to compare select cases of severe TIPN (n=172) and controls without any evidence of TIPN (n=170) derived from E5103. Cases were defined as those with at least grade 3 TIPN and controls were optimally. matched by demographic and risk factors and had no reported evidence for TIPN of any grade. Germline WES was conducted using Ion Proton™ Sequencers from Life Technologies with an average >100X coverage of the exome. Rare variants with a minor allele frequency <3% predicted to be deleterious by protein prediction programs were retained for the analysis. 7,278 genes passed quality control and were included in the analysis, setting the threshold for significance at a p-value < 6.87 ×10-6 after Bonferroni correction. Results: Cytochrome P450 oxidoreductase (POR) was significantly associated with an increased risk of grade 3+ TIPN (p =1.82 ×10-6). Six variants predicted to be deleterious in POR were identified in the study population. Paclitaxel is predominately metabolized by cytochrome P450 (CYP) 2C8 and 3A4. A functional cytochrome P450 oxidoreductase is required for the catalytic activities of all 57 CYP family members to metabolize drugs, xenobiotics, and steroid hormones. Conclusion: Rare variants in cytochrome P450 oxidoreductase predicted an increased risk of severe TIPN in patients receiving paclitaxel. These rare variants in POR may modulate the catalytic activities of P450 enzymes that are responsible for paclitaxel metabolism and have a striking biological rationale as contributors to TIPN. Work is ongoing to validate these findings mechanistically and to identify strategies to nullify the impact of these deleterious variants. Citation Format: Fei Shen, Guanglong Jiang, Laura Gardner, Gloria Xue, Santosh Philips, Reynold Ly, Osei Wilberforce, Xi Wu, Erica Cantor, Chau Dang, Donald Northfelt, Todd Skaar, Kathy D. Miller, George Sledge, Bryan P Schneider. Cytochrome P450 reductase gene, POR, associated with paclitaxel induced peripheral neuropathy in patients of European ancestry from the adjuvant breast cancer trial, ECOG-ACRIN E5103 [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P1-08-02.