Venclyxto: Uses, Dosage & Side Effects
A selective BCL-2 inhibitor used to treat chronic lymphocytic leukemia (CLL) and acute myeloid leukemia (AML) by restoring programmed cancer cell death
Venclyxto (venetoclax) is a targeted anticancer medication belonging to a class of drugs known as BCL-2 inhibitors. It is used to treat adults with chronic lymphocytic leukemia (CLL) and acute myeloid leukemia (AML). Venetoclax works by blocking the BCL-2 protein, which cancer cells use to survive and evade the body’s natural cell death processes. By inhibiting BCL-2, Venclyxto restores programmed cell death (apoptosis) in cancer cells, reducing the number of malignant cells in the blood and bone marrow. Venclyxto is taken orally as a tablet and may be used alone or in combination with other cancer treatments. It requires careful dose escalation to reduce the risk of tumor lysis syndrome, a potentially serious complication.
Quick Facts: Venclyxto
Key Takeaways
- Venclyxto (venetoclax) is a first-in-class BCL-2 inhibitor that works by blocking the BCL-2 protein, restoring the ability of cancer cells to undergo programmed cell death (apoptosis), and is used to treat chronic lymphocytic leukemia (CLL) and acute myeloid leukemia (AML).
- Tumor lysis syndrome (TLS) is a serious risk, particularly during the initial dose ramp-up phase. Patients must drink plenty of water (at least 1.5–2 liters daily), start on a low dose that is gradually increased, and have regular blood tests to monitor for TLS.
- Strong CYP3A4 inhibitors (such as ketoconazole, itraconazole, posaconazole, voriconazole, clarithromycin, and ritonavir) are contraindicated during the dose ramp-up phase in CLL due to the increased risk of TLS. Grapefruit, Seville oranges, and starfruit must also be avoided.
- Venclyxto must always be taken with a meal at approximately the same time each day. The tablets should be swallowed whole with water and not chewed, crushed, or broken.
- Women of childbearing potential must use highly effective contraception during treatment and for at least 30 days after the last dose; hormonal contraceptives may be less effective with Venclyxto, so a barrier method must also be used.
What Is Venclyxto and What Is It Used For?
Venclyxto contains the active substance venetoclax, a targeted anticancer medication that represents a significant breakthrough in the treatment of blood cancers. Unlike traditional chemotherapy, which kills rapidly dividing cells indiscriminately, venetoclax is designed to target a specific molecular vulnerability that many cancer cells rely upon for survival. This targeted approach has transformed outcomes for patients with CLL and AML, particularly those who may not be suitable for intensive chemotherapy regimens.
The drug belongs to a class of medications called BCL-2 inhibitors. BCL-2 (B-cell lymphoma 2) is a protein that plays a critical role in regulating apoptosis, the body’s natural process of programmed cell death. In healthy tissue, apoptosis is a carefully controlled mechanism that eliminates damaged, aging, or unnecessary cells. However, many cancer cells – particularly those found in CLL and AML – produce excessive amounts of BCL-2 protein, which effectively shields them from the apoptotic signals that would normally trigger their destruction. By overexpressing BCL-2, these cancer cells can survive indefinitely and continue to accumulate in the blood, bone marrow, and lymph nodes.
Venetoclax works by binding directly to the BCL-2 protein with high selectivity and affinity. When venetoclax occupies the binding groove of BCL-2, it displaces pro-apoptotic proteins such as BIM (BCL-2-interacting mediator of cell death) that were previously sequestered by BCL-2. The release of these pro-apoptotic proteins triggers the mitochondrial apoptotic pathway, leading to the activation of caspases and ultimately the programmed death of the cancer cell. Because venetoclax targets BCL-2 specifically, it is most effective against cancers that are highly dependent on this protein for survival.
Chronic Lymphocytic Leukemia (CLL)
CLL is a type of cancer that affects the white blood cells called lymphocytes. In CLL, the bone marrow produces abnormal lymphocytes that multiply too quickly and live too long, gradually accumulating in the blood, lymph nodes, spleen, and bone marrow. Over time, these abnormal cells crowd out healthy blood cells, leading to symptoms such as fatigue, frequent infections, easy bruising or bleeding, and enlarged lymph nodes. CLL is the most common type of leukemia in adults in Western countries, typically affecting people over the age of 60.
Venclyxto is approved for the treatment of adults with CLL in the following settings:
- In combination with obinutuzumab: For previously untreated CLL patients. This fixed-duration regimen has shown high rates of undetectable minimal residual disease (uMRD), a marker associated with longer remissions.
- In combination with rituximab: For CLL patients whose disease has relapsed after or not responded to at least one prior line of therapy. The MURANO trial demonstrated superior progression-free survival compared to the previous standard of care.
- As monotherapy (single agent): For CLL patients who have received at least one prior therapy, or for previously untreated patients with 17p deletion or TP53 mutation who are not suitable for other treatments, or for patients who have failed both chemo-immunotherapy and a B-cell receptor pathway inhibitor.
Acute Myeloid Leukemia (AML)
AML is a type of cancer that affects the myeloid cells in the bone marrow. In AML, the bone marrow produces large numbers of immature, abnormal white blood cells (blasts) that accumulate rapidly and interfere with the production of normal blood cells. This leads to a deficiency of red blood cells (anemia), normal white blood cells (increasing infection risk), and platelets (leading to bleeding problems). AML is an aggressive cancer that typically requires prompt treatment.
Venclyxto is approved for the treatment of adults with newly diagnosed AML who are not eligible for intensive chemotherapy. In this setting, it is given in combination with a hypomethylating agent, either azacitidine or decitabine. The VIALE-A trial demonstrated a significant improvement in overall survival when venetoclax was combined with azacitidine compared to azacitidine alone in this patient population, establishing a new standard of care for older or unfit AML patients.
Venclyxto represents a new approach to cancer treatment by specifically targeting the BCL-2 protein that cancer cells depend on for survival. Unlike conventional chemotherapy, which damages both cancerous and healthy cells, this targeted mechanism aims to selectively eliminate cancer cells while causing less harm to normal tissues. However, because BCL-2 is also present in some healthy cells (particularly certain immune cells), side effects including low blood cell counts can still occur.
What Should You Know Before Taking Venclyxto?
Contraindications
There are specific situations in which Venclyxto must not be used. Understanding these contraindications is essential for safe treatment.
- Hypersensitivity: Do not take Venclyxto if you are allergic to venetoclax or any of the other ingredients in the tablets (listed in the contents section below).
- Strong CYP3A4 inhibitors during CLL dose ramp-up: If you have CLL, you must not take certain medications during the initial dose ramp-up phase (typically the first 5 weeks of treatment). These include itraconazole, ketoconazole, posaconazole, and voriconazole (antifungal drugs), clarithromycin (an antibiotic), and ritonavir (an HIV medication). This restriction exists because these drugs can dramatically increase venetoclax levels in the blood, substantially raising the risk of life-threatening tumor lysis syndrome. Your doctor can advise when these medications may be restarted after you reach the full target dose.
- St. John’s wort: Do not take the herbal supplement St. John’s wort (Hypericum perforatum), used for mild depression and anxiety, while taking Venclyxto. St. John’s wort is a strong CYP3A4 inducer that can significantly reduce venetoclax blood levels and make the treatment less effective.
Warnings and Precautions
TLS is a potentially life-threatening condition that can occur when cancer cells are destroyed rapidly by Venclyxto. The breakdown products of dying cancer cells can overwhelm the kidneys and cause dangerous changes in blood chemistry, including elevated potassium, uric acid, and phosphate levels, and reduced calcium levels. This can lead to kidney failure, abnormal heart rhythms, seizures, and death. The risk of TLS is highest during the initial dose ramp-up period. Seek immediate medical attention if you experience fever or chills, nausea or vomiting, confusion, difficulty breathing, irregular heartbeat, dark or cloudy urine, unusual tiredness, muscle pain or joint discomfort, seizures, or abdominal pain and swelling.
Before and during treatment with Venclyxto, tell your doctor if any of the following apply to you:
- Kidney problems: Impaired kidney function increases your risk of tumor lysis syndrome. Your doctor will assess your kidney function before starting treatment and may need to take extra precautions, such as hospitalizing you for monitoring during dose increases, providing intravenous fluids, and performing more frequent blood tests.
- Liver problems: Liver impairment may affect how your body processes venetoclax, potentially increasing drug levels and the risk of side effects. Your doctor may need to reduce your dose of Venclyxto.
- Infections: Venclyxto can lower your white blood cell count (particularly neutrophils), which increases your susceptibility to infections. If you currently have an infection, have had a long-lasting infection, or have experienced repeated infections, inform your doctor. Some infections during Venclyxto treatment can be serious, including pneumonia and sepsis (blood poisoning), which can be life-threatening.
- Vaccinations: Do not receive live vaccines during treatment with Venclyxto. Your immune system may not be able to mount a proper response, and live vaccines could cause infection in immunocompromised patients. Inactivated vaccines may be less effective. Discuss your vaccination schedule with your doctor before starting treatment.
Managing TLS Risk
Your medical team will take several measures to reduce the risk of tumor lysis syndrome:
- Blood tests: Regular blood chemistry monitoring will be performed before treatment, during dose increases, and periodically throughout treatment to detect early signs of TLS.
- Uric acid medication: Before starting Venclyxto, your doctor may prescribe medications such as allopurinol to prevent the buildup of uric acid in the body, which is one of the hallmarks of TLS.
- Hydration: Drinking plenty of water (at least 1.5 to 2 liters per day) helps the kidneys flush out the breakdown products of dying cancer cells. You should begin drinking this amount two days before starting Venclyxto and continue during dose increases.
- Hospitalization: If your doctor assesses that you are at higher risk for TLS (for example, if you have a high tumor burden or impaired kidney function), you may need to be treated in the hospital during certain dose increases so that you can receive intravenous fluids, have blood tests taken more frequently, and be monitored for complications.
Pregnancy and Breastfeeding
Venclyxto must not be used during pregnancy, as there are no adequate data on its safety in pregnant women. Based on its mechanism of action and findings from animal studies, venetoclax may cause harm to the developing fetus. If you are pregnant, think you may be pregnant, or are planning to become pregnant, talk to your doctor before taking this medicine.
Women of childbearing potential must use a highly effective method of contraception during treatment with Venclyxto and for at least 30 days after the last dose. Importantly, because Venclyxto may reduce the effectiveness of hormonal contraceptives (such as birth control pills, patches, or implants), an additional barrier method (such as a condom) must be used alongside any hormonal contraception. If you become pregnant during treatment, inform your doctor immediately.
Breastfeeding is not recommended during treatment with Venclyxto. It is not known whether venetoclax or its metabolites pass into breast milk, and a risk to the breastfed infant cannot be excluded.
Animal studies suggest that Venclyxto may impair male fertility by reducing sperm count. Men should discuss sperm preservation options with their doctor before starting treatment.
Driving and Operating Machinery
You may feel tired or dizzy after taking Venclyxto. If this occurs, do not drive or operate tools or machinery until the symptoms resolve. These effects are more common during the initial weeks of treatment.
Important Information About Ingredients
Venclyxto tablets contain less than 1 mmol sodium (23 mg) per tablet, which means they are essentially sodium-free. This is relevant for patients on sodium-restricted diets.
How Does Venclyxto Interact with Other Drugs?
Venetoclax is primarily metabolized by the CYP3A4 enzyme system in the liver, making it susceptible to interactions with drugs that inhibit or induce this enzyme. Additionally, venetoclax can affect the blood levels of certain other medications through its effects on transport proteins such as P-glycoprotein (P-gp) and BCRP. It is essential to inform your doctor about all medications, supplements, and herbal products you are taking before starting Venclyxto.
Major Interactions
| Interacting Drug | Effect | Clinical Significance |
|---|---|---|
| Itraconazole, ketoconazole, posaconazole, voriconazole (strong CYP3A4 inhibitors) | Dramatically increased venetoclax levels, greatly elevated TLS risk | Contraindicated during CLL dose ramp-up; if unavoidable at full dose, reduce venetoclax dose by at least 75% |
| Clarithromycin (strong CYP3A4 inhibitor / antibiotic) | Significantly increased venetoclax plasma levels | Contraindicated during CLL dose ramp-up; consider alternative antibiotics |
| Ritonavir (strong CYP3A4 inhibitor / HIV medication) | Markedly increased venetoclax exposure | Contraindicated during CLL dose ramp-up; dose adjustment required at full dose |
| Rifampicin (strong CYP3A4 inducer) | Dramatically reduced venetoclax levels (up to 87% decrease in exposure) | Avoid combination; venetoclax efficacy may be severely compromised |
| Carbamazepine, phenytoin (strong CYP3A4 inducers / antiepileptics) | Significantly reduced venetoclax levels | Avoid combination; efficacy may be diminished |
| St. John’s wort (Hypericum perforatum) | Substantially reduced venetoclax levels | Contraindicated – do not use together |
Other Important Interactions
| Interacting Drug | Effect | Clinical Significance |
|---|---|---|
| Fluconazole, ciprofloxacin, erythromycin, diltiazem, verapamil (moderate CYP3A4 inhibitors) | Increased venetoclax levels (moderate increase) | Dose reduction of venetoclax by at least 50% may be required; monitor closely |
| Efavirenz, etravirine, modafinil, bosentan (moderate CYP3A4 inducers) | Moderately reduced venetoclax levels | Avoid if possible; efficacy may be reduced |
| Warfarin, dabigatran (anticoagulants) | Venetoclax may increase levels of these drugs via P-gp inhibition | Monitor INR closely (warfarin); adjust anticoagulant dose as needed |
| Digoxin (cardiac glycoside) | Venetoclax may increase digoxin levels via P-gp inhibition | Monitor digoxin levels; take digoxin at least 6 hours before or after venetoclax |
| Everolimus, sirolimus (immunosuppressants) | Venetoclax may increase levels of these drugs | Monitor drug levels closely; dose adjustment may be needed |
| Statins (cholesterol-lowering drugs) | Venetoclax may increase statin levels via BCRP/OATP inhibition | Monitor for statin-related side effects (muscle pain) |
| Cholestyramine, colestipol, colesevelam (bile acid sequestrants) | May reduce venetoclax absorption | Avoid combination; may reduce venetoclax effectiveness |
Do not eat grapefruit, Seville oranges (bitter oranges, commonly used in marmalade), or starfruit (carambola) while taking Venclyxto. Do not drink juice made from these fruits or take supplements containing them. These fruits contain natural substances that inhibit CYP3A4 and can significantly increase venetoclax levels in the blood, raising the risk of serious side effects.
Always tell your doctor or pharmacist about all medications you are taking, have recently taken, or might take, including over-the-counter medicines, vitamins, and herbal supplements. Your doctor may need to adjust your dose of Venclyxto or switch you to an alternative medication to avoid dangerous interactions.
What Is the Correct Dosage of Venclyxto?
Venclyxto should always be taken exactly as prescribed by your doctor. The dose is gradually increased (ramped up) to reduce the risk of tumor lysis syndrome. Do not change your dose or stop taking Venclyxto without consulting your doctor first.
Dosage for Chronic Lymphocytic Leukemia (CLL)
For CLL, treatment begins with a low dose that is increased weekly over 5 weeks until the full target dose of 400 mg daily is reached. During this ramp-up period, you will receive a new pack of tablets each week.
| Week | Daily Dose | Tablets |
|---|---|---|
| Week 1 | 20 mg | Two 10 mg tablets |
| Week 2 | 50 mg | One 50 mg tablet |
| Week 3 | 100 mg | One 100 mg tablet |
| Week 4 | 200 mg | Two 100 mg tablets |
| Week 5 onwards | 400 mg | Four 100 mg tablets |
Venclyxto Monotherapy (Single Agent)
Indication: CLL after prior therapy, or untreated CLL with 17p deletion/TP53 mutation
Dose: 400 mg once daily (after completing the 5-week ramp-up)
Duration: Continue as long as effective and tolerable
Venclyxto + Rituximab
Indication: Relapsed or refractory CLL
Dose: 400 mg once daily (after completing the 5-week ramp-up)
Duration: 24 months of venetoclax treatment. Rituximab is started after the ramp-up is complete.
Venclyxto + Obinutuzumab
Indication: Previously untreated CLL
Dose: 400 mg once daily (after completing the 5-week ramp-up)
Duration: Approximately 10 months of venetoclax treatment. Obinutuzumab is started first and continued for 6 cycles.
Dosage for Acute Myeloid Leukemia (AML)
For AML, the dose ramp-up is faster, increasing daily over 3 days to the full dose of 400 mg.
| Day | Daily Dose | Tablets |
|---|---|---|
| Day 1 | 100 mg | One 100 mg tablet |
| Day 2 | 200 mg | Two 100 mg tablets |
| Day 3 onwards | 400 mg | Four 100 mg tablets |
Venclyxto + Azacitidine or Decitabine (AML)
Indication: Newly diagnosed AML in patients not eligible for intensive chemotherapy
Dose: 400 mg once daily (after completing the 3-day ramp-up)
Duration: Continue until disease progression or unacceptable side effects
During AML treatment, you may be hospitalized during the ramp-up period so that your doctor can ensure you have adequate hydration, prescribe medications to prevent uric acid buildup, and monitor your blood chemistry for signs of TLS.
How to Take Venclyxto
- Take with a meal: Venclyxto must always be taken with food at approximately the same time each day. Food increases the absorption of venetoclax, which is important for consistent drug levels.
- Swallow whole: Swallow the tablets whole with a glass of water. Do not chew, crush, or break the tablets.
- Morning dosing recommended: During the initial ramp-up period, take your tablets in the morning to facilitate any follow-up blood tests that may be required later in the day.
- If you vomit: If you vomit after taking Venclyxto, do not take an additional dose that day. Take your next dose at the usual time the following day.
Hydration Requirements (CLL Patients)
Drinking adequate amounts of water is critically important during the first 5 weeks of Venclyxto treatment for CLL to help reduce the risk of tumor lysis syndrome:
- Begin drinking at least 1.5 to 2 liters of water per day starting 2 days before your first dose of Venclyxto.
- Continue drinking at least 1.5 to 2 liters on the day you start taking Venclyxto and during the ramp-up period.
- Drink the same amount for 2 days before and on the day of each dose increase.
- Non-alcoholic, caffeine-free drinks also count toward your daily fluid intake. However, do not drink grapefruit juice, Seville orange juice, or starfruit juice.
Missed Dose
If you forget to take your dose of Venclyxto:
- If fewer than 8 hours have passed since you would normally take your dose, take it as soon as possible.
- If more than 8 hours have passed, skip the missed dose and take your next dose at the regular time the next day.
- Do not take a double dose to make up for the missed one.
Overdose
If you take more Venclyxto than you should, contact your doctor, pharmacist, or go to a hospital emergency department immediately. Take the tablets and this information with you so the healthcare team knows what you have taken.
Do not stop taking Venclyxto unless your doctor tells you to. Stopping treatment prematurely without medical guidance may allow your cancer to progress. If you have any questions about how long you should continue taking this medicine, discuss them with your doctor.
What Are the Side Effects of Venclyxto?
Like all medicines, Venclyxto can cause side effects, although not everyone gets them. The types and frequency of side effects can differ depending on whether you are being treated for CLL or AML, and whether Venclyxto is given alone or with other medications. Your medical team will monitor you closely and manage side effects as they arise.
Serious Side Effects
Stop taking Venclyxto and seek immediate medical attention if you experience: fever or chills; nausea or vomiting; confusion; difficulty breathing; irregular heartbeat; dark or cloudy urine; unusual tiredness; muscle pain or joint discomfort; seizures; or abdominal pain and swelling.
Your doctor will monitor your blood counts during treatment. Signs of infection may include fever, chills, weakness or confusion, cough, or pain or burning during urination. Some infections, such as pneumonia or sepsis (blood poisoning), can be serious and life-threatening. Contact your doctor immediately if you develop any signs of infection.
Side Effects in CLL Patients
Very Common
May affect more than 1 in 10 people
- Pneumonia (lung infection)
- Upper respiratory tract infection (runny nose, sore throat, cough)
- Diarrhea
- Nausea or vomiting
- Constipation
- Fatigue
- Decreased red blood cell count (anemia)
- Decreased lymphocyte count
- Elevated potassium levels
- Elevated phosphate levels
- Decreased calcium levels
Common
May affect up to 1 in 10 people
- Sepsis (serious blood infection)
- Urinary tract infection
- Febrile neutropenia (fever with low white blood cells)
- Elevated creatinine levels (indicator of kidney function)
- Elevated urea levels
Side Effects in AML Patients
Very Common
May affect more than 1 in 10 people
- Nausea or vomiting
- Diarrhea
- Mouth sores (stomatitis)
- Fatigue or weakness
- Lung or blood infection
- Decreased appetite
- Joint pain (arthralgia)
- Dizziness or fainting
- Headache
- Shortness of breath (dyspnea)
- Bleeding
- Low blood pressure (hypotension)
- Urinary tract infection
- Weight loss
- Abdominal pain
- Decreased platelets (thrombocytopenia)
- Febrile neutropenia (fever with low white blood cells)
- Anemia (decreased red blood cells)
- Elevated total bilirubin
- Low potassium levels
Common
May affect up to 1 in 10 people
- Gallstones (cholelithiasis)
- Gallbladder infection (cholecystitis)
If you experience any side effects, including those not listed here, tell your doctor or nurse. You can also report suspected side effects to your national pharmacovigilance authority (e.g., the EMA in Europe, the FDA MedWatch program in the United States, or the MHRA Yellow Card Scheme in the United Kingdom) to help monitor the ongoing benefit-risk profile of Venclyxto.
How Should You Store Venclyxto?
Keep this medicine out of the sight and reach of children. Do not use Venclyxto after the expiry date which is stated on the blister, label, and outer carton after “EXP”. The expiry date refers to the last day of that month.
- Storage conditions: There are no special storage requirements for Venclyxto tablets. Store at room temperature.
- Disposal: Do not throw away any medicines via wastewater or household waste. Ask your pharmacist how to throw away medicines you no longer use. These measures help protect the environment.
What Does Venclyxto Contain?
Active Substance
The active substance is venetoclax. It is available in three strengths:
- 10 mg tablets: Each film-coated tablet contains 10 mg venetoclax.
- 50 mg tablets: Each film-coated tablet contains 50 mg venetoclax.
- 100 mg tablets: Each film-coated tablet contains 100 mg venetoclax.
Inactive Ingredients (Excipients)
Tablet core: copovidone (K 28), polysorbate 80 (E433), colloidal anhydrous silica (E551), anhydrous calcium hydrogen phosphate (E341 (ii)), sodium stearyl fumarate.
Film coating:
- 10 mg tablets: Yellow iron oxide (E172), polyvinyl alcohol (E1203), titanium dioxide (E171), macrogol 3350 (E1521), talc (E553b).
- 50 mg tablets: Yellow iron oxide (E172), red iron oxide (E172), black iron oxide (E172), polyvinyl alcohol (E1203), titanium dioxide (E171), macrogol 3350 (E1521), talc (E553b).
- 100 mg tablets: Yellow iron oxide (E172), polyvinyl alcohol (E1203), titanium dioxide (E171), macrogol 3350 (E1521), talc (E553b).
Appearance and Pack Sizes
The 10 mg tablet is pale yellow, round, 6 mm in diameter, debossed with “V” on one side and “10” on the other. The 50 mg tablet is beige, oblong, 14 mm long, debossed with “V” on one side and “50” on the other. The 100 mg tablet is pale yellow, oblong, 17.2 mm long, debossed with “V” on one side and “100” on the other.
Venclyxto tablets are supplied in blister packs or bottles in the following configurations:
- 10 mg: 10 tablets (5 blisters × 2) or 14 tablets (7 blisters × 2)
- 50 mg: 5 tablets (5 blisters × 1) or 7 tablets (7 blisters × 1)
- 100 mg: 7 tablets (7 blisters × 1), 14 tablets (7 blisters × 2), 112 tablets (4 × 28), or 360 tablets (3 bottles × 120)
Not all pack sizes may be marketed in all countries.
Manufacturer
Venclyxto is manufactured and marketed by AbbVie Deutschland GmbH & Co. KG, Knollstrasse, 67061 Ludwigshafen, Germany. In the United States, the same molecule is marketed as Venclexta by AbbVie Inc. and Genentech.
Frequently Asked Questions About Venclyxto
Venclyxto (venetoclax) is used to treat adults with chronic lymphocytic leukemia (CLL) and acute myeloid leukemia (AML). For CLL, it can be given alone or in combination with rituximab or obinutuzumab. For AML, it is used with azacitidine or decitabine in newly diagnosed patients who are not eligible for intensive chemotherapy. It works by blocking the BCL-2 protein that cancer cells rely on for survival.
Tumor lysis syndrome (TLS) occurs when cancer cells are killed rapidly and release their contents into the bloodstream. This can cause dangerously high levels of potassium, uric acid, and phosphate, and low calcium levels, potentially leading to kidney failure, irregular heartbeat, seizures, and even death. Venclyxto is particularly effective at destroying cancer cells, so TLS risk is highest during the initial dose ramp-up period. This is why the dose is gradually increased, blood tests are performed frequently, and patients must drink plenty of water.
Grapefruit, Seville oranges, and starfruit contain natural compounds that inhibit the CYP3A4 enzyme, which is responsible for breaking down venetoclax in the body. Eating these fruits, drinking their juice, or taking supplements containing them can significantly increase venetoclax blood levels, raising the risk of serious side effects including tumor lysis syndrome. This applies throughout the entire course of treatment, not just during the dose ramp-up phase.
The duration of Venclyxto treatment depends on your condition and regimen. For CLL with rituximab, treatment lasts 24 months. For CLL with obinutuzumab, the venetoclax component lasts approximately 10 months. For CLL monotherapy, treatment continues as long as the drug remains effective and tolerable. For AML, treatment continues until disease progression or intolerable side effects. Your doctor will determine the appropriate duration for your individual situation.
No, Venclyxto should not be used during pregnancy as it may harm the unborn baby. Women of childbearing potential must use highly effective contraception during treatment and for at least 30 days after the last dose. Because Venclyxto may reduce the effectiveness of hormonal contraceptives (such as the pill), a barrier method (such as a condom) must also be used. Breastfeeding is not recommended during treatment. Men should discuss sperm preservation before starting treatment, as the drug may affect fertility.
Venclyxto has demonstrated impressive clinical efficacy in CLL. In the MURANO trial for relapsed/refractory CLL, the combination of venetoclax and rituximab achieved a 5-year progression-free survival rate of approximately 53%, compared to 5% for the previous standard of care (bendamustine plus rituximab). In the CLL14 trial for previously untreated CLL, venetoclax plus obinutuzumab achieved high rates of undetectable minimal residual disease, with sustained remissions even after treatment completion. The drug is effective regardless of TP53 status, making it an important option for patients with high-risk genetic features.
References
- European Medicines Agency (EMA). Venclyxto (venetoclax) – Summary of Product Characteristics. Last updated 2025. Available from: EMA EPAR.
- U.S. Food and Drug Administration (FDA). Venclexta (venetoclax) Prescribing Information. Revised 2024. Available from: FDA Drug Label.
- Seymour JF, Kipps TJ, Eichhorst B, et al. Venetoclax–Rituximab in Relapsed or Refractory Chronic Lymphocytic Leukemia (MURANO). N Engl J Med. 2018;378(12):1107–1120. doi:10.1056/NEJMoa1713976.
- Fischer K, Al-Sawaf O, Bahlo J, et al. Venetoclax and Obinutuzumab in Patients with CLL and Coexisting Conditions (CLL14). N Engl J Med. 2019;380(23):2225–2236. doi:10.1056/NEJMoa1815281.
- DiNardo CD, Jonas BA, Pullarkat V, et al. Azacitidine and Venetoclax in Previously Untreated Acute Myeloid Leukemia (VIALE-A). N Engl J Med. 2020;383(7):617–629. doi:10.1056/NEJMoa2012971.
- Al-Sawaf O, Zhang C, Tandon M, et al. Venetoclax plus obinutuzumab versus chlorambucil plus obinutuzumab for previously untreated chronic lymphocytic leukaemia (CLL14): follow-up results from a multicentre, open-label, randomised, phase 3 trial. Lancet Oncol. 2020;21(9):1188–1200.
- National Comprehensive Cancer Network (NCCN). NCCN Clinical Practice Guidelines in Oncology: Chronic Lymphocytic Leukemia/Small Lymphocytic Lymphoma. Version 1.2025.
- Eichhorst B, Robak T, Montserrat E, et al. Chronic lymphocytic leukaemia: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up. Ann Oncol. 2024;35(1):90–115.
- World Health Organization (WHO). WHO Model List of Essential Medicines – 23rd List. Geneva: WHO; 2023.
- Kater AP, Wu JQ, Kipps TJ, et al. Venetoclax Plus Rituximab in Relapsed Chronic Lymphocytic Leukemia: 4-Year Results and Evaluation of Impact of Genomic Complexity and Prior Therapy in the MURANO Phase III Study. J Clin Oncol. 2020;38(34):4042–4054.
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