Introduction: Chronic lymphocytic leukemia (CLL) is commonly treated with the B-cell lymphoma 2 inhibitor (BCL-2) venetoclax. Venetoclax is associated with an increased risk of tumor lysis syndrome in this patient population. Because venetoclax undergoes CYP3A4 metabolism, strong CYP3A4 inhibitors are contraindicated during the ramp-up phase of venetoclax in patients with CLL.
Case report: Our case report describes a 58 year old male initially diagnosed with CLL in 2013, whose first-line treatment consisted of ibrutinib. The patient developed a central nervous system (CNS) aspergillosis infection in 2018, and was initiated on voriconazole. He was subsequently under active surveillance until his disease progressed. The patient was started on venetoclax therapy, while on concomitant voriconazole, for management of his CLL.
Management and outcome: The patient's initial venetoclax dose was 10 mg daily, and he received rasburicase on day 1 of therapy. He tolerated a modified ramp-up phase without complication. After receiving 9 days of inpatient therapy, the patient was discharged on 50 mg of venetoclax to continue outpatient dose escalation. His dose was ultimately escalated to 100 mg daily.
Discussion: Although this report describes the safe administration of venetoclax with voriconazole, extreme caution should be exercised when administering venetoclax with any strong CYP3A4 inhibitor during the ramp-up phase in patients with CLL.
Keywords: CLL; CYP3A4; TLS; venetoclax; voriconazole.