Abstract 5032: The relationship between the UGT1A1*27 and UGT1A1*7 genetic polymorphisms and irinotecan-related toxicities in patients with lung cancer

Abstract Background: Genetic polymorphisms in the UDP-glucuronosyltransferase 1A1 (UGT1A1), UGT1A7, and UGT1A9 genes are associated with interindividual differences in irinotecan toxicities. The UGT1A1*7, *27, and *29 gene polymorphisms occur within the common exons of UGT1A1 isoforms and cause substantial reductions in their functional activity; however, few clinical studies have examined the effects of these polymorphisms. Purpose: To evaluate the effects of gene polymorphisms, including UGT1A1*7, *27, and *29, on the safety of irinotecan therapy. Patients and methods: The eligibility criteria were as follows: lung cancer patients who were scheduled to undergo irinotecan therapy, aged ≥20 years, and had a performance status of 0-2. After informed consent had been obtained, patients were enrolled, and their blood was collected and used to examine the frequency of the UGT1A1*6, *7, *27, *28, and *29 polymorphisms and the drug concentrations of irinotecan, SN-38, and SN-38G after irinotecan therapy. Results: Thirty-one patients were enrolled. The patients’ characteristics were as follows: male/female = 25/6, median age (range) = 71 (55-84), stage IIB/IIIA/IIIB/IV = 2/6/11/12, and Ad/Sq/Sm/Oth = 14/10/3/4. The -/-, *6/-, *7/-, *27/-, *28/-, and *29/- UGT1A1 gene polymorphisms were observed in 10 (32%), 10 (32%), 2 (6%), 2 (6%), 7 (23%), and 0 (0%) cases, respectively. There were no homozygous or complex heterozygous polymorphisms. The UGT1A1*27 polymorphism occurred separately from the UGT1A1*28 polymorphism. The lowest leukocyte counts of the patients with the UGT1A1*27 and UGT1A1*6 gene polymorphisms were lower than those seen in the wild-type patients. SN-38 tended to remain in the blood for a prolonged period after the infusion of irinotecan in patients with the UGT1A1*27 or UGT1A1*28 polymorphism. No severe myelotoxicity was seen in the patients with UGT1A1*7. Conclusions: UGT1A1*27 and UGT1A1*7 are both rare gene polymorphisms. UGT1A1*27 can occur separately from UGT1A1*28 in some circumstances and is related to leukopenia during irinotecan treatment. UGT1A1*7 is less relevant to irinotecan-induced toxicities, and UGT1A1*29 seems to have little clinical impact. Citation Format: Minoru Fukuda, Manabu Okumura, Tomomi Iwakiri, Arimori Kazuhiko, Shinnosuke Takemoto, Takaya Ikeda, Takuya Honda, Hiroyuki Yamaguchi, Katsumi Nakatomi, Kazuma Kobayashi, Mitsuko Masutani, Mikio Oka, Kazuto Ashizawa, Hiroshi Mukae. The relationship between the UGT1A1*27 and UGT1A1*7 genetic polymorphisms and irinotecan-related toxicities in patients with lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5032. doi:10.1158/1538-7445.AM2017-5032