Document Type : Research Articles
Authors
1
Clinical Pharmacy Department, Faculty of Pharmacy, Heliopolis University, Cairo, Egypt.
2
Pharmacology and Toxicology Department, Faculty of Pharmacy, Cairo University, Cairo, Egypt.
3
Clinical Pharmacy Department, Faculty of Pharmacy, Misr University for Science and Technology, Cairo, Egypt.
4
Egypt Healthcare Authority, Cairo, Egypt.
5
Pharmaceutical Services Department and Personalized Medication Management Unit, Children’s Cancer Hospital Egypt (57357), Cairo, Egypt.
6
Research Department, Children’s Cancer Hospital Egypt (57357), Cairo, Egypt.
7
Pediatric Medical Oncology, Beni Suef University and Children’s Cancer Hospital Egypt (57357), Cairo, Egypt.
8
Pediatric Oncology Department, National Cancer Institute, Cairo University and Children’s Cancer Hospital Egypt 57357, Cairo, Egypt.
Abstract
Objectives: Rhabdomyosarcoma (RMS) accounts for 50% of soft tissue sarcomas and 7% of pediatric malignancies. Cyclophosphamide (CPA) is the cornerstone of therapy and is a prodrug that is activated by the highly polymorphic drug-metabolizing enzyme CYP3A5. We aim to examine the possible CYP3A5 polymorphism association with CPA efficacy, survival outcomes, and toxicity in Egyptian pediatric RMS patients. Methods: The three non-functional SNPs, CYP3A5*3 rs776746 (C_26201809_30), CYP3A5*6 rs10264272 (C_30203950_10), and CYP3A5*7 rs41303343 (C_32287188_10) were genotyped by real-time PCR. We conducted a cohort retrospective study of 150 pediatric RMS patients treated with CPA-based first-line treatment to analyze the association between these genotypes and CPA efficacy/toxicities in RMS patients. Key findings: The frequency of having normal, intermediate, and poor metabolizers was 4.7%, 34%, and 61.3%, respectively. There was an association between these different phenotypes, genotypes, and CPA efficacy/toxicity. Hemorrhagic cystitis and pancytopenia were present in all patients, while nephrotoxicity incidence was 87.3%. There was a notable difference in the occurrence of hemorrhagic cystitis among CYP3A5 intermediate metabolizers *1/*3, *1/*6, and poor metabolizers *3/*3, *3/*6 with a significance level of p<0.05. Neither CYP3A5*7 polymorphism nor *6/*6 genotype was identified in our study. Conclusion: Our results demonstrate that CYP3A5*3 (rs776746) and CYP3A5*6 (rs10264272) have a great association with CPA efficacy and toxicity in RMS patients.
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