VENETOCLAX
Clinical safety rating: caution
Comprehensive clinical and safety monograph for VENETOCLAX (VENETOCLAX).
Venetoclax is a selective B-cell lymphoma-2 (BCL-2) inhibitor. It binds directly to the BCL-2 protein, displacing pro-apoptotic proteins such as BIM, leading to mitochondrial outer membrane permeabilization and activation of caspases, resulting in apoptosis. BCL-2 is overexpressed in various hematologic malignancies, particularly chronic lymphocytic leukemia (CLL) and acute myeloid leukemia (AML).
| Metabolism | Primarily metabolized by cytochrome P450 (CYP) 3A4/5. Less than 1% excreted unchanged in urine and feces. Co-administration with strong CYP3A inhibitors increases exposure (AUC) by approximately 5-7 fold; with strong CYP3A inducers decreases exposure. |
| Excretion | Primarily fecal (approximately 99.9%), with less than 1% excreted renally as unchanged drug. Biliary/fecal elimination is the major route, with negligible renal clearance. |
| Half-life | Terminal elimination half-life ranges from 14 to 27 hours (mean ~16 hours) in patients with hematologic malignancies. At steady state, accumulation is minimal; once-daily dosing maintains therapeutic concentrations. |
| Protein binding | High plasma protein binding (>99.9%), primarily to human serum albumin (HSA). No significant binding to alpha-1-acid glycoprotein. |
| Volume of Distribution | Volume of distribution (Vd) is approximately 2.5-5 L (or 0.03-0.07 L/kg based on 70 kg). This low Vd indicates limited extravascular distribution, primarily confined to plasma and well-perfused tissues. |
| Bioavailability | Oral bioavailability is approximately 65-85% (mean 73%) under fed conditions (low-fat meal). Food increases absorption: high-fat meal increases exposure by 3-4 fold relative to fasting. Coadministration with a low-fat meal is recommended. |
| Onset of Action | Oral: Onset of pharmacodynamic effect (e.g., reduction in tumor burden) is observed within days to weeks, with initial tumor lysis syndrome risk within 24-48 hours of first dose. Time to clinical response varies by indication, typically within weeks. |
| Duration of Action | Duration of action after single dose is prolonged due to half-life, supporting once-daily dosing. Continuous therapy is required for sustained effect; drug levels return to baseline within 5-7 days after discontinuation. |
| Molecular Weight | 868.45 |
Oral, 400 mg once daily after a 5-week ramp-up schedule (20 mg daily for 1 week, 50 mg daily for week 2, 100 mg daily for week 3, 200 mg daily for week 4, then 400 mg daily thereafter). For CLL/SLL, continue until disease progression or unacceptable toxicity. For AML, dosing is 600 mg daily on days 2-21 in combination with azacitidine or decitabine, or 400 mg daily on days 2-21 with low-dose cytarabine.
| Dosage form | TABLET |
| Renal impairment | No dose adjustment required for GFR ≥30 mL/min. For CLL/SLL patients with GFR <30 mL/min, use with caution and consider dose reduction; specific guidelines not established. For AML, no adjustment needed for GFR ≥30 mL/min; for GFR <30 mL/min, avoid use due to limited data. |
| Liver impairment | Child-Pugh A: No adjustment. Child-Pugh B: Reduce dose by 50% (e.g., 200 mg daily after ramp-up). Child-Pugh C: Reduce dose to 100 mg daily; monitor closely. For AML, dosing recommendations for hepatic impairment are not established; use with caution. |
| Pediatric use | Safety and efficacy not established in pediatric patients. No recommended dose. |
| Geriatric use | No specific dose adjustment required based on age alone. Monitor renal function and comorbidities; elderly patients may be more susceptible to tumor lysis syndrome and infections. Start at standard dose with appropriate prophylaxis. |
| 1st trimester | Avoid unless no alternative; associated with embryo-fetal toxicity based on animal studies (e.g., post-implantation loss and skeletal anomalies). |
| 2nd trimester | Avoid; risk of fetal harm due to mechanism of action (BCL-2 inhibition may affect fetal cell survival). |
| 3rd trimester | Avoid; potential for fetal toxicity and adverse effects on fetal hematopoiesis. |
Clinical note
Comprehensive clinical and safety monograph for VENETOCLAX (VENETOCLAX).
| Placental transfer | Venetoclax is expected to cross the placenta; molecular weight (868.45 Da) suggests potential transfer. |
| Breastfeeding | No data on presence in human milk; due to potential for serious adverse reactions in nursing infants (e.g., hematologic toxicity), breastfeeding is not recommended during therapy and for at least 1 week after last dose. |
■ FDA Black Box Warning
BOXED WARNING: TUMOR LYSIS SYNDROME (TLS). Venetoclax can cause tumor lysis syndrome, including fatal events, often within the first 24 to 48 hours of the initial dose and during dose escalation. Patients with high tumor burden (lymph nodes >5 cm or absolute lymphocyte count ≥25 × 10^9/L) are at increased risk. Assess baseline risk and provide prophylactic hydration, antihyperuricemics, and monitoring; reduce or interrupt dosing as needed.
| Serious Effects |
Concurrent use with strong CYP3A inhibitors (e.g., ketoconazole, ritonavir) at initiation and during ramp-up phase due to risk of tumor lysis syndrome.Concurrent use with strong CYP3A inducers (e.g., rifampin, carbamazepine) due to reduced efficacy.Pregnancy (unless no alternative and patient informed).
| Precautions | Tumor Lysis Syndrome (TLS): Assess risk; provide prophylaxis (hydration, antihyperuricemics) and monitor blood chemistries; manage with dose interruption and adjustments, Neutropenia: May occur; monitor complete blood counts and manage with dose interruption, reduction, or colony-stimulating factors, Infections: Monitor for signs of infection; serious infections including fatal events have occurred, Immunization: Live vaccines are not recommended during treatment and until B-cell recovery, Hepatic Impairment: Reduce dose in patients with severe hepatic impairment (Child-Pugh C), Drug Interactions: Avoid concomitant use with strong or moderate CYP3A inhibitors (consider dose reduction if unavoidable) and strong CYP3A inducers; avoid grapefruit products, Concomitant Use with P-gp and BCRP Substrates: Monitor for toxicity of these substrates |
Loading safety data…
| Lactation Rating | L5 (contraindicated) |
| Teratogenic Risk | Venetoclax is embryotoxic and fetotoxic in animal studies. In first trimester, there is potential for teratogenicity; in second and third trimesters, risk of fetal harm and reduced fetal growth. Human data limited. |
| Fetal Monitoring | Monitor complete blood count, electrolytes, and tumor lysis syndrome parameters. Consider fetal growth ultrasound in third trimester if used in pregnancy. |
| Fertility Effects | Venetoclax may impair fertility in females based on animal studies showing effects on estrous cycle and ovarian follicle depletion. No data on male fertility. |
| Food/Dietary | Administer with food to increase absorption (up to 5-fold). Avoid grapefruit, grapefruit juice, Seville oranges, star fruit, and pomegranate (CYP3A4 inhibitors). No restriction on other foods. |
| Clinical Pearls | Venetoclax requires a 5-week ramp-up schedule to reduce risk of tumor lysis syndrome (TLS). Prophylaxis includes hydration, uric acid reduction (allopurinol or rasburicase), and monitoring of electrolytes and renal function. Use with strong CYP3A4 inhibitors contraindicated; reduce dose with moderate inhibitors. Administer with food to enhance absorption. |
| Patient Advice | Take venetoclax exactly as prescribed, with a meal and water, at the same time each day. · Swallow tablets whole; do not crush, chew, or break them. · You will need frequent blood tests to monitor for tumor lysis syndrome and other side effects. · Avoid grapefruit, Seville oranges, star fruit, and pomegranate while on this medication. · Tell your doctor about all other medicines you take, especially antifungal or antibiotic drugs. · Do not stop taking venetoclax without consulting your doctor, even if you feel well. |