Bosutinib Zentiva: Uses, Dosage & Side Effects
A tyrosine kinase inhibitor (TKI) targeting BCR-ABL for the treatment of Philadelphia chromosome-positive chronic myeloid leukemia (Ph+ CML) in adults
Bosutinib Zentiva (bosutinib) is a second-generation tyrosine kinase inhibitor (TKI) used in the treatment of Philadelphia chromosome-positive chronic myeloid leukemia (Ph+ CML). It works by blocking the BCR-ABL fusion protein, a key driver of CML cell growth. Bosutinib Zentiva is a generic form of bosutinib, approved for newly diagnosed adult patients with chronic phase Ph+ CML and for those previously treated with one or more TKIs when imatinib, nilotinib, and dasatinib are not considered appropriate. It is taken orally once daily with food and requires specialist prescription and regular monitoring of blood counts and liver function.
Quick Facts: Bosutinib Zentiva
Key Takeaways
- Bosutinib Zentiva is a second-generation BCR-ABL tyrosine kinase inhibitor used to treat Philadelphia chromosome-positive chronic myeloid leukemia (Ph+ CML) in adults.
- It is taken once daily with food; food significantly increases absorption and should not be skipped.
- Diarrhea is the most common side effect, particularly in the first few weeks, and is usually manageable with supportive care.
- Regular monitoring of liver function, blood counts, and kidney function is essential throughout treatment.
- Strong CYP3A4 inhibitors and inducers should be avoided as they significantly alter bosutinib blood levels.
What Is Bosutinib Zentiva and What Is It Used For?
Bosutinib Zentiva contains the active substance bosutinib, which belongs to a class of medicines called tyrosine kinase inhibitors (TKIs). These targeted therapies are designed to interfere with specific molecular pathways that cancer cells use to grow and survive. In the case of chronic myeloid leukemia, the target is the BCR-ABL fusion protein, an abnormal enzyme created by the Philadelphia chromosome translocation that is present in approximately 95% of CML cases.
The Philadelphia chromosome results from a reciprocal translocation between chromosomes 9 and 22, denoted as t(9;22)(q34;q11), which creates the BCR-ABL oncogene. This fusion gene produces a constitutively active tyrosine kinase that drives uncontrolled proliferation of myeloid cells in the bone marrow. Bosutinib potently inhibits this BCR-ABL kinase, as well as Src-family kinases that also play a role in CML disease progression.
Bosutinib Zentiva is specifically approved for two clinical situations. First, it can be used as a first-line treatment in newly diagnosed adult patients with chronic phase Philadelphia chromosome-positive CML. Second, it is indicated for adult patients with chronic, accelerated, or blast phase Ph+ CML who have been previously treated with one or more tyrosine kinase inhibitors and for whom imatinib, nilotinib, and dasatinib are not considered appropriate treatment options. This makes bosutinib a valuable option for patients who have experienced resistance or intolerance to other TKIs.
Unlike first-generation TKIs such as imatinib, bosutinib has a dual kinase inhibitory profile targeting both ABL and Src-family kinases. However, it has relatively low activity against c-KIT and platelet-derived growth factor receptor (PDGFR), which may contribute to a more favorable hematologic safety profile compared to some other TKIs. Clinical trials, including the pivotal BFORE study for newly diagnosed patients, have demonstrated that bosutinib achieves high rates of major molecular response (MMR) and complete cytogenetic response (CCyR) in CML patients.
As a generic formulation manufactured by Zentiva, Bosutinib Zentiva contains the same active ingredient as the originator product Bosulif and has been demonstrated to be bioequivalent. This means it delivers the same therapeutic effect at the same dosage. The availability of generic bosutinib helps improve patient access to this important cancer therapy.
What Should You Know Before Taking Bosutinib Zentiva?
Contraindications
Bosutinib Zentiva must not be used in certain situations. You should not take this medicine if you are allergic (hypersensitive) to bosutinib or any of the other ingredients in the tablet. Patients with hepatic (liver) impairment should not use bosutinib, as the drug is extensively metabolized in the liver and impaired liver function can lead to dangerously elevated drug levels. Your doctor will perform liver function tests before starting treatment and regularly throughout therapy.
Do not take Bosutinib Zentiva if you have significant liver impairment or if you are allergic to bosutinib or any of its excipients. Always inform your doctor of your complete medical history before starting treatment.
Warnings and Precautions
Several important warnings apply to bosutinib therapy. Hepatotoxicity (liver damage) is a significant concern. Elevated liver enzymes (ALT and AST) have been reported in clinical trials, with some cases of severe hepatotoxicity. Your doctor should monitor liver function tests monthly for the first three months and then as clinically indicated. If liver enzyme elevations occur, your doctor may need to temporarily interrupt treatment, reduce the dose, or permanently discontinue the medication.
Diarrhea is extremely common during bosutinib treatment, particularly during the first few weeks. While usually manageable with anti-diarrheal medications such as loperamide, severe diarrhea can lead to dehydration and electrolyte imbalances. Patients should be advised to report persistent or severe diarrhea immediately. Adequate fluid intake is essential, and your doctor may prescribe anti-diarrheal medications proactively.
Myelosuppression (suppression of bone marrow function) can occur, leading to low blood cell counts including neutropenia (low white blood cells), thrombocytopenia (low platelets), and anemia (low red blood cells). Complete blood counts should be performed weekly for the first month and then monthly thereafter, or as clinically indicated. Dose modifications or treatment interruption may be necessary if blood counts fall below acceptable thresholds.
Fluid retention, including pleural effusion (fluid around the lungs), pericardial effusion (fluid around the heart), pulmonary edema, and peripheral edema, has been reported. Patients should be monitored for signs and symptoms of fluid retention, including unexplained weight gain, swelling, or shortness of breath. Cardiac monitoring is recommended, particularly in patients with risk factors for cardiac disease.
Renal toxicity has been observed, and kidney function should be monitored before and during treatment. Pancreatitis has been reported rarely and lipase levels should be assessed if abdominal symptoms develop.
Regular monitoring of liver function (monthly for 3 months, then as needed), complete blood counts (weekly for 1 month, then monthly), kidney function, and lipase levels is essential during treatment with Bosutinib Zentiva.
Pregnancy and Breastfeeding
Bosutinib Zentiva must not be used during pregnancy. Animal studies have demonstrated embryo-fetal toxicity, including skeletal abnormalities, at clinically relevant doses. The potential risk to human fetuses is considered significant. Women of childbearing potential must use highly effective contraception during treatment and for at least one month after the final dose. A pregnancy test should be performed before initiating therapy.
Male patients with female partners of childbearing potential should also use effective contraception during treatment and for at least one month after the last dose. Men considering fathering a child should discuss sperm banking with their healthcare provider before starting treatment, as bosutinib may affect male fertility.
It is not known whether bosutinib or its metabolites are excreted in human breast milk. Because of the potential for serious adverse reactions in nursing infants, breastfeeding must be discontinued during treatment and for at least two weeks after the final dose. The decision to discontinue breastfeeding or to discontinue therapy should take into account the benefit of treatment for the mother.
How Does Bosutinib Zentiva Interact with Other Drugs?
Drug interactions are a critical consideration with bosutinib therapy because the drug is primarily metabolized by the cytochrome P450 enzyme CYP3A4 in the liver. Any medication that significantly affects CYP3A4 activity can alter bosutinib plasma concentrations, potentially leading to increased toxicity or reduced efficacy. Additionally, bosutinib absorption is pH-dependent, meaning medications that alter gastric pH can reduce its bioavailability.
Understanding these interactions is essential for safe prescribing. Your healthcare provider should review all medications, including prescription drugs, over-the-counter products, herbal remedies, and dietary supplements, before initiating bosutinib therapy and whenever medications are changed during treatment.
Major Interactions
| Drug / Class | Type | Effect | Recommendation |
|---|---|---|---|
| Ketoconazole, itraconazole, voriconazole | Strong CYP3A4 inhibitor | Increases bosutinib levels up to 8-fold | Avoid concomitant use |
| Ritonavir, cobicistat | Strong CYP3A4 inhibitor | Significantly increases bosutinib exposure | Avoid concomitant use |
| Rifampicin (rifampin) | Strong CYP3A4 inducer | Decreases bosutinib levels by ~94% | Avoid concomitant use |
| Phenytoin, carbamazepine | Strong CYP3A4 inducer | Significantly reduces bosutinib efficacy | Avoid concomitant use |
| St. John's Wort (Hypericum) | Strong CYP3A4 inducer | May reduce bosutinib plasma levels | Contraindicated |
| Proton pump inhibitors (omeprazole, lansoprazole) | Gastric acid suppressor | Reduces bosutinib absorption | Avoid long-term co-administration; use short-acting antacids with timing separation |
| Grapefruit, Seville oranges | CYP3A4 inhibitor (dietary) | Increases bosutinib plasma levels | Avoid during treatment |
Minor Interactions
Moderate CYP3A4 inhibitors such as erythromycin, fluconazole, diltiazem, and aprepitant may increase bosutinib levels to a lesser degree than strong inhibitors. If co-administration cannot be avoided, your doctor may consider reducing the bosutinib dose and monitoring more closely for adverse effects. Moderate CYP3A4 inducers such as efavirenz and modafinil may moderately reduce bosutinib levels.
Bosutinib may also affect the levels of other drugs. It is a weak inhibitor of CYP3A4 and may slightly increase levels of CYP3A4 substrates. Caution should be used when co-administering bosutinib with narrow therapeutic index drugs such as warfarin, cyclosporine, or certain statins. Bosutinib may also inhibit P-glycoprotein (P-gp), potentially increasing levels of P-gp substrates such as digoxin.
H2-receptor antagonists (such as ranitidine or famotidine) and antacids may also reduce bosutinib absorption, though to a lesser extent than proton pump inhibitors. If an antacid is needed, it should be administered more than 2 hours before or after bosutinib dosing. Short-acting antacids are preferred over long-acting acid suppressants.
What Is the Correct Dosage of Bosutinib Zentiva?
Bosutinib Zentiva dosing is determined by the clinical setting and must be individualized by a specialist physician experienced in treating CML. The tablets should be swallowed whole with food, as food significantly increases bioavailability by approximately 70%. Taking bosutinib on an empty stomach substantially reduces absorption and should be avoided.
Adults
| Indication | Starting Dose | Dose Escalation | Maximum Dose |
|---|---|---|---|
| Newly diagnosed chronic phase Ph+ CML | 400 mg once daily with food | May increase to 500 mg/day if inadequate response at 8-12 weeks | 600 mg/day |
| Previously treated CML (chronic, accelerated, or blast phase) | 500 mg once daily with food | May increase to 600 mg/day if inadequate response and no significant adverse events | 600 mg/day |
Dose escalation should only be considered in patients who do not achieve an adequate hematologic, cytogenetic, or molecular response at the expected time points and who are not experiencing significant grade 3 or higher adverse events at the current dose. The decision to escalate should be made by the treating hematologist or oncologist based on European LeukemiaNet (ELN) response milestones.
Dose reductions may be necessary for adverse events. Common dose modification triggers include diarrhea grade 3 or higher, liver enzyme elevations exceeding 5 times the upper limit of normal, clinically significant myelosuppression, and other grade 3-4 non-hematologic toxicities. The dose may be reduced in 100 mg increments. If 300 mg once daily is not tolerated, discontinuation should be considered.
Dose Adjustments for Hepatotoxicity
If ALT or AST exceeds 5x upper limit of normal (ULN): withhold bosutinib until recovery to ≤2.5x ULN, then resume at a dose reduced by 100 mg. If recovery takes longer than 4 weeks, consider discontinuation. If elevations recur at the reduced dose, discontinue treatment.
Dose Adjustments for Myelosuppression
If ANC <1.0 x 109/L or platelets <50 x 109/L: withhold bosutinib until ANC ≥1.0 x 109/L and platelets ≥50 x 109/L. If recovery occurs within 2 weeks, resume at the same dose. If blood counts remain low for more than 2 weeks, resume at a dose reduced by 100 mg upon recovery.
Children
Bosutinib Zentiva is not approved for use in children and adolescents under 18 years of age. The safety and efficacy of bosutinib in the pediatric population have not been established. Pediatric CML is typically managed with other approved TKIs such as imatinib or dasatinib, depending on the clinical scenario and local guidelines.
Elderly
No specific dose adjustment is recommended for elderly patients based on age alone. However, elderly patients may be more susceptible to certain adverse effects, particularly hepatotoxicity, fluid retention, and cardiac events. Closer monitoring is advisable in patients over 65 years of age. Renal function, which naturally declines with age, should be assessed before and during treatment, as impaired renal function may increase bosutinib exposure.
Missed Dose
If a dose is missed, the patient should take the next scheduled dose at the regular time. A double dose should not be taken to make up for the missed one. If vomiting occurs after taking a dose, an additional dose should not be taken; the patient should simply take the next scheduled dose. Consistent daily dosing is important for maintaining therapeutic drug levels and optimizing treatment outcomes.
Overdose
There is limited clinical experience with bosutinib overdose. In clinical trials, isolated cases of overdose have been reported. Symptoms of overdose are expected to be an exaggeration of the known side effects, particularly gastrointestinal toxicity (severe diarrhea, nausea, vomiting), hepatotoxicity, and myelosuppression. There is no specific antidote for bosutinib. In the event of overdose, supportive care should be provided, and the patient should be closely monitored for adverse effects. Given the high protein binding of bosutinib (~94%), hemodialysis is unlikely to be effective.
What Are the Side Effects of Bosutinib Zentiva?
Like all medicines, Bosutinib Zentiva can cause side effects, although not everybody gets them. The side effect profile of bosutinib has been well characterized in multiple clinical trials involving thousands of patients. Understanding the frequency and nature of these side effects can help patients and healthcare providers manage them effectively. Many side effects are most pronounced during the initial weeks of therapy and tend to diminish with continued treatment.
It is important to report any new or worsening symptoms to your healthcare provider promptly. Some side effects, particularly hepatotoxicity and severe myelosuppression, require immediate medical attention and may necessitate dose modification or treatment discontinuation. Regular monitoring through blood tests is essential to detect early signs of potentially serious adverse effects.
Very Common
May affect more than 1 in 10 people
- Diarrhea (most frequent, typically early in treatment)
- Nausea
- Vomiting
- Abdominal pain
- Thrombocytopenia (low platelet count)
- Anemia (low red blood cell count)
- Neutropenia (low white blood cell count)
- Rash
- Fatigue
- Elevated liver enzymes (ALT, AST)
- Decreased appetite
- Headache
- Pyrexia (fever)
- Respiratory tract infection
Common
May affect up to 1 in 10 people
- Pleural effusion (fluid around the lungs)
- Peripheral edema (swelling)
- Dizziness
- Cough
- Dyspnea (shortness of breath)
- Pruritus (itching)
- Arthralgia (joint pain)
- Myalgia (muscle pain)
- Back pain
- Elevated lipase
- Elevated bilirubin
- Renal impairment or elevated creatinine
- QT prolongation on electrocardiogram
- Pneumonia
- Hyperkalemia (elevated potassium)
- Dehydration
- Chest pain
Uncommon
May affect up to 1 in 100 people
- Pericardial effusion (fluid around the heart)
- Pulmonary edema
- Acute pancreatitis
- Hepatotoxicity (severe liver damage)
- Anaphylactic shock
- Erythema multiforme (severe skin reaction)
- Respiratory failure
- Pulmonary hypertension
Rare
May affect up to 1 in 1,000 people
- Stevens-Johnson syndrome
- Drug-induced liver failure
- Tumor lysis syndrome
Severe diarrhea with dehydration, yellowing of the skin or eyes (jaundice), significant bleeding or bruising, severe chest pain or shortness of breath, high fever with signs of infection, severe skin reactions, or swelling of the face, lips, tongue, or throat (anaphylaxis). These symptoms may indicate a serious complication requiring urgent medical care.
Gastrointestinal side effects, particularly diarrhea, are typically most severe during the first 1-2 months of treatment and usually decrease in frequency and severity thereafter. Proactive management with anti-diarrheal agents such as loperamide, adequate hydration, and dietary modifications can help mitigate these symptoms. Your healthcare provider may recommend starting loperamide at the first sign of diarrhea and maintaining adequate fluid intake throughout treatment.
Hepatotoxicity deserves special attention. Liver enzyme elevations (ALT, AST) typically occur within the first three months of treatment. Grade 3-4 elevations (more than 5 times the upper limit of normal) have been reported in approximately 7-9% of patients in clinical trials. Monthly liver function monitoring for the first three months and periodic monitoring thereafter is mandatory. In most cases, hepatotoxicity is reversible with dose interruption or reduction.
How Should You Store Bosutinib Zentiva?
Proper storage of Bosutinib Zentiva is essential to maintain the quality and effectiveness of the medication throughout its shelf life. The film-coated tablets should be stored at temperatures not exceeding 30°C (86°F). They should be kept in the original blister packaging to protect from moisture and light. Do not remove tablets from the blister until you are ready to take them.
Keep this medicine out of the sight and reach of children. Bosutinib is a cytotoxic (cancer-killing) medication, and accidental ingestion by a child could be extremely dangerous. Store the tablets in a secure location that is not accessible to children or pets.
Do not use Bosutinib Zentiva after the expiry date printed on the packaging (the expiry date refers to the last day of that month). If you notice any visible changes in the appearance of the tablets, such as discoloration, crumbling, or unusual odor, do not use them and consult your pharmacist.
Do not dispose of unused medicines via household waste or wastewater. Return any unused or expired bosutinib tablets to your pharmacist for proper disposal. This is important because bosutinib is a cytotoxic agent that could pose environmental risks if improperly discarded. Many pharmacies and healthcare facilities offer medication take-back programs for safe disposal of unused cancer medications.
What Does Bosutinib Zentiva Contain?
Understanding the full composition of Bosutinib Zentiva is important, particularly for patients with known allergies or sensitivities to specific pharmaceutical excipients. The active and inactive ingredients are listed below.
Active ingredient: Each film-coated tablet contains 100 mg of bosutinib (as bosutinib monohydrate). Bosutinib monohydrate is the pharmaceutical salt form used to ensure consistent absorption and stability of the active substance.
Tablet core excipients: The inactive ingredients in the tablet core typically include microcrystalline cellulose (a bulking agent), croscarmellose sodium (a disintegrant to help the tablet break apart in the stomach), poloxamer 188 (a solubilizer), povidone (a binder), and magnesium stearate (a lubricant used during manufacturing). These excipients are commonly used in pharmaceutical manufacturing and are generally well tolerated.
Film coating: The film coating typically contains polyvinyl alcohol, titanium dioxide (E171), macrogol/polyethylene glycol, and talc. The film coating provides protection for the tablet, aids in swallowing, and may contain iron oxide yellow (E172) for coloring depending on the specific formulation.
Patients with lactose intolerance should note that some bosutinib formulations may contain small amounts of lactose. However, the Zentiva formulation should be reviewed for this specific excipient by consulting the patient information leaflet included in the packaging or asking your pharmacist. If you have any known allergies to medications or food additives, inform your pharmacist or doctor before starting treatment.
Frequently Asked Questions About Bosutinib Zentiva
Bosutinib Zentiva is used to treat Philadelphia chromosome-positive chronic myeloid leukemia (Ph+ CML) in adults. It can be prescribed as a first-line treatment for newly diagnosed chronic phase CML, or for patients who have previously been treated with other tyrosine kinase inhibitors (such as imatinib, nilotinib, or dasatinib) when those treatments are no longer appropriate. It works by blocking the BCR-ABL protein that drives leukemia cell growth.
Take Bosutinib Zentiva once daily with food, as this significantly increases absorption. Swallow the tablet whole with water at approximately the same time each day. Do not crush, break, or chew the tablet. If you miss a dose, take your next dose at the regular scheduled time; do not double up. If you vomit after taking a dose, do not take another one.
Diarrhea is very common with bosutinib, especially during the first few weeks. Drink plenty of fluids to stay hydrated. Your doctor may recommend anti-diarrheal medication such as loperamide. Avoid foods that may worsen diarrhea (spicy, fatty, or high-fiber foods). If diarrhea is severe (more than 6 loose stools per day), persistent, or accompanied by fever or dehydration, contact your healthcare provider immediately as dose modification may be needed.
Proton pump inhibitors (such as omeprazole or lansoprazole) should be avoided with bosutinib as they significantly reduce its absorption. If you need an antacid, use short-acting formulations and take them at least 2 hours before or after your bosutinib dose. H2-receptor antagonists (such as famotidine) may also reduce absorption. Discuss any acid-reducing medications with your doctor before starting bosutinib.
Bosutinib Zentiva is a generic version of bosutinib (originally marketed as Bosulif). It contains the same active ingredient (bosutinib) at the same strength and has been demonstrated to be bioequivalent to the originator product. This means it delivers the same amount of drug into the bloodstream and is expected to have the same therapeutic effect. Generic medicines undergo rigorous regulatory review to confirm their quality, safety, and efficacy before approval.
Treatment with bosutinib is typically long-term, often continuing for years as long as it remains effective and tolerable. CML is a chronic condition that usually requires ongoing treatment to keep the disease under control. Some patients who achieve a deep and sustained molecular response may be eligible for treatment-free remission (TFR) attempts under close medical supervision, but this decision should only be made by your specialist. Never stop taking bosutinib without consulting your doctor.
References
- European Medicines Agency (EMA). Bosulif (bosutinib) - Summary of Product Characteristics. Last updated 2025.
- U.S. Food and Drug Administration (FDA). Bosulif (bosutinib) - Prescribing Information. Revised 2024.
- Cortes JE, Gambacorti-Passerini C, Deininger MW, et al. Bosutinib versus imatinib for newly diagnosed chronic myeloid leukemia: results from the randomized BFORE trial. J Clin Oncol. 2018;36(3):231-237.
- Hochhaus A, Baccarani M, Silver RT, et al. European LeukemiaNet 2020 recommendations for treating chronic myeloid leukemia. Leukemia. 2020;34(4):966-984.
- National Comprehensive Cancer Network (NCCN). Clinical Practice Guidelines in Oncology: Chronic Myeloid Leukemia. Version 1.2025.
- Gambacorti-Passerini C, Cortes JE, Lipton JH, et al. Safety of bosutinib versus imatinib in the phase 3 BFORE trial in newly diagnosed chronic phase chronic myeloid leukemia. Leukemia. 2020;34(8):2154-2163.
- Brummendorf TH, Cortes JE, Milojkovic D, et al. Bosutinib (BOS) versus imatinib for newly diagnosed chronic phase (CP) chronic myeloid leukemia (CML): final 5-year results from the BFORE trial. Blood. 2022;140(Suppl 1):7642-7644.
- World Health Organization (WHO). WHO Model List of Essential Medicines. 23rd List, 2023.
- Cortes JE, Kantarjian HM, Brummendorf TH, et al. Safety and efficacy of bosutinib (SKI-606) in chronic phase Philadelphia chromosome-positive chronic myeloid leukemia patients with resistance or intolerance to imatinib. Blood. 2011;118(17):4567-4576.
- European Society for Medical Oncology (ESMO). Chronic Myeloid Leukemia: ESMO Clinical Practice Guidelines. Ann Oncol. 2024;35(1):1-20.
iMedic Medical Editorial Team
This article has been written and reviewed by the iMedic Medical Editorial Team, consisting of licensed physicians and pharmacists specializing in hematology, oncology, and clinical pharmacology. Our content follows the GRADE evidence framework and adheres to international guidelines from EMA, FDA, NCCN, ELN, and ESMO.
Hematology & Oncology Specialists
Board-certified hematologists and oncologists with expertise in chronic myeloid leukemia and targeted therapy management.
Clinical Pharmacologists
Specialists in drug interactions, pharmacokinetics, and medication safety with focus on oncology pharmaceuticals.
Medical Researchers
Research professionals with access to the latest clinical trial data and systematic reviews in CML treatment.
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