Abstract

Objective: Venetoclax, an oral B-cell lymphoma-2 inhibitor, necessitates dose adjustment when combined with a CYP3A4 inhibitor; however, the dosing regimen remains unclear on adding a CYP3A4 inhibitor after venetoclax administration.
Case summary: We present a case report of a patient who was simultaneously treated with a CYP3A4 inhibitor and a steady daily dose of venetoclax. A 30-year-old male diagnosed with acute myeloid leukemia received a combination of venetoclax and azacitidine as remission induction therapy. He was prescribed 400 mg/day venetoclax at a steady daily dose, with fosfluconazole initiated on day 18. Given that fosfluconazole can induce moderate CYP3A4 inhibitory effects, the venetoclax dosage was reduced to 200 mg/day on the same day. Despite dose reduction, plasma trough levels of venetoclax continued rising gradually. Nearly 10 days were required to decrease blood levels to a steady state.
Conclusion: The risk of elevated venetoclax blood levels needs to be considered when initiating CYP3A4 inhibitors and reducing venetoclax dosage on the same day.

Author Details

Authors

• Toshiki Kubo¹
• Shunsuke Matsuo¹
• Rintaro Sogawa¹
• Takeo Yasu²
• Toshiaki Nagaie³
• Sho Okamoto³
• Shinya Kimura³
• Chisato Shimanoe¹

Departments

• ¹ Department of Pharmacy, Saga University Hospital, Saga,
• ² Department of Medicinal Therapy Research, Pharmaceutical Education and Research Center, Meiji Pharmaceutical University, Tokyo, and
• ³ Division of Hematology, Respiratory Medicine and Oncology, Department of Internal Medicine, Faculty of Medicine, Saga University, Saga, Japan

Address

Shunsuke Matsuo, PhD
Department of Pharmacy
Saga University Hospital
5-1-1 Nabeshima
Saga 849-8501, Japan
Email: [email protected]

Citation