Blenrep (Belantamab Mafodotin)
Antibody-drug conjugate for multiple myeloma — given in combination with bortezomib/dexamethasone or pomalidomide/dexamethasone
Blenrep (belantamab mafodotin) is an antibody-drug conjugate used in combination with other cancer medicines to treat adults with multiple myeloma. It works by targeting B-cell maturation antigen (BCMA) on myeloma cells, delivering a cytotoxic agent directly into cancer cells to destroy them. Blenrep is administered as an intravenous infusion in a hospital setting and requires regular eye examinations due to its potential to cause corneal changes. This guide covers uses, dosage, side effects, and essential safety information for patients and caregivers.
Quick Facts
Key Takeaways
- Blenrep is an antibody-drug conjugate that targets BCMA on multiple myeloma cells, used in combination with bortezomib/dexamethasone or pomalidomide/dexamethasone.
- Regular ophthalmological examinations are mandatory before each of the first four doses, as Blenrep can cause corneal changes that may affect vision.
- Preservative-free lubricating eye drops must be used at least four times daily throughout treatment to protect the corneal surface.
- Common side effects include eye problems (blurred vision, dry eyes), low blood cell counts (thrombocytopenia, neutropenia), infections, fatigue, and gastrointestinal symptoms.
- Contact lenses should not be worn during treatment unless specifically advised otherwise by an ophthalmologist.
What Is Blenrep and What Is It Used For?
Blenrep contains the active substance belantamab mafodotin, which belongs to a class of cancer medicines known as antibody-drug conjugates (ADCs). This innovative treatment approach combines the precision targeting of a monoclonal antibody with the cancer-killing power of a cytotoxic agent called monomethyl auristatin F (MMAF). The antibody component is specifically engineered to recognise and bind to B-cell maturation antigen (BCMA), a protein that is abundantly expressed on the surface of multiple myeloma cells.
Once the antibody binds to BCMA on a myeloma cell, the entire antibody-drug conjugate complex is internalised. Inside the cell, the cytotoxic payload MMAF is released, where it disrupts the cell's microtubule network — a critical structure involved in cell division. This disruption ultimately leads to the death of the myeloma cell through a process called apoptosis (programmed cell death). Importantly, because the antibody is designed to target only cells expressing BCMA, the drug preferentially destroys cancerous cells while aiming to limit damage to healthy tissues.
Multiple myeloma is a cancer that originates in the plasma cells of the bone marrow. Plasma cells are a type of white blood cell normally responsible for producing antibodies that help fight infections. In multiple myeloma, these plasma cells become cancerous and multiply uncontrollably, producing abnormal proteins and crowding out healthy blood cells. This can lead to bone destruction, kidney problems, weakened immunity, and anaemia. Multiple myeloma is often a relapsing disease, meaning patients may respond to initial therapy but later experience disease progression, requiring additional lines of treatment.
Blenrep is specifically indicated for use in combination with other cancer medicines:
- Bortezomib and dexamethasone (BVd regimen) — bortezomib is a proteasome inhibitor that blocks a key protein-recycling process in cancer cells, while dexamethasone is a corticosteroid with anti-inflammatory and anti-myeloma properties.
- Pomalidomide and dexamethasone (BPd regimen) — pomalidomide is an immunomodulatory drug that enhances the immune system's ability to fight cancer and directly inhibits myeloma cell growth.
Because Blenrep is always used as part of a combination regimen, it is essential that patients also read and understand the prescribing information for the other medicines in their treatment plan. If you have any questions about these companion therapies, your oncologist or haematologist can provide detailed guidance.
What Should You Know Before Taking Blenrep?
Contraindications
Do not use Blenrep if you are allergic to belantamab mafodotin or any of the other ingredients in this medicine. The excipients include sodium citrate monohydrate (E330), trehalose dihydrate, disodium edetate, and polysorbat 80 (E433). If you think you may be allergic, consult your doctor before receiving treatment.
Warnings and Precautions
Speak with your doctor or nurse before you use Blenrep if you have any of the following conditions. Your healthcare team needs to be aware of these to ensure your treatment is as safe and effective as possible.
Eye Problems (Ocular Toxicity)
Blenrep can cause significant changes to the surface of the eye, particularly the corneal epithelium. These changes may lead to blurred vision, dry eyes, photophobia (light sensitivity), a sensation of having something in the eye, eye irritation, eye pain, reduced visual acuity, and in some cases, the development of cataracts. This is one of the most important safety considerations with Blenrep, and strict ophthalmological monitoring is required throughout treatment.
- You must have an eye examination by an ophthalmologist before each of the first four doses. Your doctor may order additional eye examinations during continued treatment.
- Do not wear contact lenses during treatment unless your ophthalmologist specifically advises otherwise.
- Use preservative-free lubricating eye drops (artificial tears) at least four times daily to moisten and lubricate your eyes. Begin before each infusion and continue throughout treatment.
- Some corneal changes can occur without symptoms and may only be detected during a professional eye examination — even if your vision seems normal, do not skip scheduled eye appointments.
If you notice any changes in your vision, report them to your doctor immediately. Your doctor may adjust the dose, change the dosing interval, or refer you to an ophthalmologist for further evaluation. Prompt reporting of visual symptoms is essential to prevent potentially serious eye complications.
Abnormal Bruising and Bleeding (Thrombocytopenia)
Blenrep can decrease the number of platelets (thrombocytes) in your blood. Platelets are small blood cells that play a critical role in blood clotting. When platelet counts fall too low, a condition known as thrombocytopenia, the risk of bleeding increases. Symptoms of low platelet counts may include:
- Unusual bruising under the skin
- Prolonged bleeding after blood draws or cuts
- Nosebleeds or bleeding gums
- More serious bleeding events
Your doctor will order blood tests before starting treatment and at regular intervals during therapy to monitor your platelet levels. If you develop unusual bleeding, bruising, or any other concerning symptoms, inform your healthcare team without delay.
Infusion-Related Reactions
As Blenrep is administered as an intravenous infusion, some patients may experience infusion-related reactions. These reactions can occur during the infusion itself or within 24 hours afterwards. In rare cases, a severe allergic reaction (anaphylaxis) may develop, which can include swelling of the face, lips, mouth, tongue, or throat, difficulty swallowing or breathing, and an itchy rash (urticaria).
Seek immediate medical attention if you think you may be having an allergic reaction. If you have previously experienced a reaction to this or any other infusion, inform your doctor or nurse before receiving subsequent doses so that appropriate precautions can be taken.
Pneumonitis (Lung Inflammation)
Serious and potentially life-threatening inflammation of the lungs (pneumonitis) has been reported in some patients receiving Blenrep. Symptoms may include shortness of breath, chest pain, and new or worsening cough. If you develop any respiratory symptoms, inform your doctor immediately. Your doctor may decide to delay or discontinue Blenrep treatment depending on the severity of the pneumonitis.
Hepatitis B Reactivation
If you have ever had hepatitis B infection, Blenrep may cause the virus to become active again (reactivation). Your doctor may test you for hepatitis B before starting treatment and monitor you for signs of infection during therapy. Symptoms of hepatitis B reactivation may include worsening fatigue, yellowing of the skin or whites of the eyes (jaundice), and dark urine. If these symptoms develop, your doctor may need to delay or stop Blenrep treatment.
Children and Adolescents
Blenrep is not intended for use in children and adolescents under 18 years of age. The safety and efficacy of this medicine have not been established in this age group, and multiple myeloma is exceedingly rare in paediatric patients.
Other Medicines and Blenrep
Tell your doctor if you are taking, have recently taken, or might take any other medicines. While no formal drug interaction studies have been conducted specifically for belantamab mafodotin, it is important for your healthcare team to have a complete picture of all your medications — including prescription drugs, over-the-counter medicines, vitamins, and herbal supplements — to ensure your treatment plan is safe and coordinated.
Pregnancy and Breastfeeding
The use of Blenrep during pregnancy may cause harm to the developing foetus, and it is not recommended during pregnancy. Before starting treatment, your doctor will discuss the potential risks, and the following precautions must be observed:
- Pregnancy testing: Women of childbearing potential must have a pregnancy test before starting Blenrep.
- Female contraception: Effective contraception must be used during treatment and for 4 months after the last dose.
- Male contraception: Effective contraception must be used during treatment and for 6 months after the last dose.
- Breastfeeding: Do not breastfeed during treatment and for 3 months after the last dose. It is unknown whether Blenrep is excreted in breast milk.
- Fertility counselling: Both men and women who wish to have children in the future should receive fertility counselling before starting treatment.
Driving and Using Machines
Blenrep can cause vision problems that may impair your ability to drive or operate machinery. Do not drive or use machines unless you are certain your vision is not affected. Discuss any concerns about your visual function with your doctor.
Important Information About Ingredients
Blenrep contains polysorbat 80 (E433), which may cause allergic reactions in some individuals. Each 70 mg vial contains 0.28 mg and each 100 mg vial contains 0.4 mg of polysorbat 80 (equivalent to 0.2 mg/mL per vial). Tell your doctor if you have any known allergies to polysorbat.
This medicine contains less than 1 mmol (23 mg) of sodium per dose, meaning it is essentially sodium-free and does not pose a concern for patients on sodium-restricted diets.
How Does Blenrep Interact with Other Drugs?
Because belantamab mafodotin is a large protein molecule (antibody-drug conjugate), it is primarily metabolised through proteolytic degradation rather than through the liver's cytochrome P450 (CYP) enzyme system. This means that traditional pharmacokinetic drug interactions are less likely compared to small-molecule drugs. However, there are important clinical considerations when using Blenrep in combination regimens.
Blenrep is always administered alongside other anti-cancer agents — either bortezomib and dexamethasone, or pomalidomide and dexamethasone. Each of these companion drugs has its own interaction profile, and the combined regimen may have additive effects on bone marrow suppression, infection risk, and other overlapping toxicities. Your oncology team will monitor for these cumulative effects throughout your treatment.
| Interacting Category | Risk / Concern | Clinical Action |
|---|---|---|
| Myelosuppressive agents | Additive bone marrow suppression (anaemia, neutropenia, thrombocytopenia) | Frequent blood count monitoring; dose adjustments may be needed |
| Live vaccines | Immunosuppression may reduce vaccine efficacy or increase risk of vaccine-strain infection | Avoid live vaccines during treatment; discuss vaccination schedule with oncologist |
| Strong CYP3A4 inhibitors/inducers | May affect levels of companion drugs (bortezomib, pomalidomide, dexamethasone) | Review companion drug prescribing information; adjust doses as needed |
| Anticoagulants and antiplatelets | Increased bleeding risk due to Blenrep-induced thrombocytopenia | Close monitoring of platelet counts and bleeding symptoms; consider dose adjustment of anticoagulant |
| Nephrotoxic agents | Potential additive renal toxicity, particularly relevant in myeloma patients with existing kidney involvement | Regular renal function monitoring; adequate hydration |
| Hepatitis B antivirals | Risk of hepatitis B reactivation in susceptible patients | Screen for HBV before treatment; consider prophylactic antiviral therapy if indicated |
Always provide your healthcare team with a complete list of all medicines, including over-the-counter products, supplements, and herbal preparations. This ensures that any potential interactions — particularly with the companion drugs in your regimen — can be identified and managed appropriately.
What Is the Correct Dosage of Blenrep?
Your doctor will determine the appropriate dose of Blenrep based on your actual body weight in kilograms. The dose is carefully calculated for each individual patient and is administered in a controlled healthcare setting by trained professionals. Blenrep is always given in combination with other anti-myeloma therapies, and the specific dosing schedule depends on which combination regimen your doctor has selected.
Adults
BVd Regimen (Blenrep + Bortezomib + Dexamethasone)
Recommended dose: 2.5 mg per kilogram of body weight
Frequency: Every 3 weeks (21-day cycle)
Administration: Intravenous infusion over approximately 30 minutes
BPd Regimen (Blenrep + Pomalidomide + Dexamethasone)
First dose: 2.5 mg per kilogram of body weight
Subsequent doses: 1.9 mg per kilogram of body weight
Frequency: Every 4 weeks (28-day cycle)
Administration: Intravenous infusion over approximately 30 minutes
| Regimen | Dose | Cycle Length | Infusion Duration |
|---|---|---|---|
| BVd (+ bortezomib + dexamethasone) | 2.5 mg/kg every cycle | 21 days (3 weeks) | ~30 minutes |
| BPd (+ pomalidomide + dexamethasone) | 2.5 mg/kg first, then 1.9 mg/kg | 28 days (4 weeks) | ~30 minutes |
Children
Blenrep is not approved for use in children or adolescents under 18 years of age. Multiple myeloma is an extremely rare malignancy in paediatric patients, and no clinical trials have been conducted in this population.
Elderly
No specific dose adjustment is required for elderly patients based solely on age. However, as with all cancer treatments, your doctor will consider your overall health status, organ function, and other medications when determining the appropriate treatment plan. Elderly patients may be more susceptible to certain side effects, particularly bone marrow suppression and infections, and may require closer monitoring.
Dose Modifications
Your doctor may adjust your dose or delay treatment based on how you respond and any side effects you experience. Common reasons for dose modification include:
- Corneal findings: Based on ophthalmological examination results, your doctor may reduce the dose or extend the interval between doses.
- Low platelet counts: If thrombocytopenia develops, treatment may be delayed until platelet counts recover sufficiently.
- Infusion-related reactions: Depending on the severity, the infusion rate may be slowed or treatment temporarily interrupted.
Missed Dose
It is very important to attend all scheduled treatment appointments. If you miss a dose, contact your doctor or hospital as soon as possible to reschedule. Do not attempt to make up for a missed dose on your own — your healthcare team will determine the best course of action to maintain the effectiveness of your treatment.
Overdose
Since Blenrep is administered by healthcare professionals in a hospital or clinic setting, the likelihood of receiving an incorrect dose is very low. In the unlikely event of an overdose, your medical team will monitor you closely for any adverse effects and provide supportive care as needed. There is no specific antidote for belantamab mafodotin.
Eye Drop Instructions During Treatment
Before each infusion, you must apply preservative-free lubricating eye drops (artificial tears). Continue using these drops at least four times daily throughout the entire duration of your Blenrep treatment. Consistent use of eye drops helps protect the corneal surface and may reduce the risk of ocular side effects. Your doctor or pharmacist can recommend a suitable preservative-free artificial tear product.
What Are the Side Effects of Blenrep?
Like all medicines, Blenrep can cause side effects, although not everybody gets them. The following information summarises the side effects that have been reported in clinical trials of Blenrep given with bortezomib and dexamethasone, and Blenrep given with pomalidomide and dexamethasone. Side effects are grouped by how frequently they occur.
Serious Side Effects — Seek Immediate Medical Attention
Certain side effects require urgent medical attention. Contact your healthcare team or seek emergency care immediately if you experience any of the following:
Very Common Serious Side Effects
- COVID-19 — fever, chills, cough, sore throat, nasal congestion, loss of taste or smell
- Pneumonia (lung infection) — shortness of breath, chest pain, new or worsening cough
- Thrombocytopenia (low platelets) — abnormal bruising, prolonged bleeding, nosebleeds
- Neutropenia (low white blood cells) — fever, chills, fatigue, increased infection risk
- Pyrexia (fever) — chills, hot flushes
Common Serious Side Effects
- COVID-19 pneumonia — breathlessness, cough, chest pain, fever, extreme fatigue, confusion
- Infusion-related reactions — flushing, chills, fever, breathing difficulties, rapid heartbeat, low blood pressure
Uncommon Serious Side Effects
- Portosinusoidal vascular disease — abnormal liver function tests, portal hypertension, oesophageal varices, ascites (fluid accumulation in the abdomen)
Other Side Effects
The following side effects have been reported with both combination regimens. Tell your doctor or nurse promptly if you notice any of these:
Very Common
- Eye problems: blurred vision, corneal surface changes, dry eyes, photophobia, foreign body sensation, eye irritation, eye pain, reduced vision, cataracts
- Upper respiratory tract infection (cold symptoms, cough, runny nose, sore throat)
- Anaemia (low red blood cells causing weakness and tiredness)
- Neutropenia and lymphopenia (low white blood cell counts)
- Insomnia (difficulty sleeping)
- Neuropathy (nerve damage, tingling, numbness)
- Cough
- Diarrhoea, nausea, constipation
- Abnormal liver function tests (elevated ALT, AST, GGT)
- Joint pain, back pain
- Fatigue
Common
- Additional eye problems: increased tearing, double vision (diplopia), itchy eyes, eye discomfort, corneal ulcers
- Urinary tract infection
- Bronchitis (airway inflammation)
- Leukopenia, febrile neutropenia
- Hypogammaglobulinaemia (low immunoglobulin levels)
- Decreased appetite
- Dyspnoea (shortness of breath)
- Vomiting, skin rash
- Abnormal creatine phosphokinase levels
- Albuminuria (protein in urine)
- Asthenia (weakness)
Uncommon
- Hepatitis B reactivation (in patients with prior hepatitis B infection)
- Pneumonitis (lung inflammation) causing shortness of breath, chest pain, and cough
Unknown Frequency
- Decreased corneal sensitivity (hypoaesthesia of the corneal surface)
Reporting Side Effects
Reporting suspected side effects after a medicine has been authorised is important. It allows continuous monitoring of the benefit-risk balance. Patients and healthcare professionals are encouraged to report any suspected adverse reactions to their national pharmacovigilance authority. In the EU, reports can be made via the European Medicines Agency (EMA); in the US, via the FDA MedWatch program; and in the UK, via the MHRA Yellow Card scheme.
How Should You Store Blenrep?
Your doctor, pharmacist, or nurse is responsible for the proper storage and handling of Blenrep, as well as for the safe disposal of any unused medicine. As a patient, you will not handle or store this medicine at home. However, the following information provides an overview of the storage requirements:
- Unopened vials: Store in a refrigerator at 2°C to 8°C. Do not freeze.
- Reconstituted solution: Can be stored for up to 4 hours at room temperature (20°C–25°C) or for up to 4 hours in a refrigerator (2°C–8°C). Do not freeze.
- Diluted infusion solution: Can be refrigerated at 2°C to 8°C for up to 24 hours before administration. If refrigerated, allow the solution to reach room temperature before infusion. The diluted solution may be kept at room temperature (20°C–25°C) for a maximum of 6 hours, including infusion time.
- Keep out of sight and reach of children.
- Do not use after the expiry date printed on the label and carton.
- Unused medicine should be disposed of in accordance with local regulations for cytotoxic waste to protect the environment.
What Does Blenrep Contain?
Active Substance
The active ingredient is belantamab mafodotin. Blenrep is available in two vial sizes:
- 70 mg vial: Contains 70 mg of belantamab mafodotin as a powder. After reconstitution with 1.4 mL of sterile water for injection, the solution contains 50 mg/mL.
- 100 mg vial: Contains 100 mg of belantamab mafodotin as a powder. After reconstitution with 2.0 mL of sterile water for injection, the solution contains 50 mg/mL.
Other Ingredients (Excipients)
- Sodium citrate monohydrate (E330)
- Trehalose dihydrate
- Disodium edetate (EDTA)
- Polysorbat 80 (E433)
Appearance and Packaging
Blenrep is supplied as a white to yellow powder in a glass vial with a rubber stopper and removable plastic cap. The powder is reconstituted to produce a clear to slightly opalescent, colourless to yellow to brown liquid. Each carton contains one single-use vial. The reconstituted solution should be inspected visually — discard if it contains visible foreign particles other than translucent to white proteinaceous particles.
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Frequently Asked Questions About Blenrep
Blenrep (belantamab mafodotin) is used in combination with other cancer medicines to treat adults with multiple myeloma, a type of bone marrow cancer. It is given together with either bortezomib and dexamethasone, or pomalidomide and dexamethasone. The medicine works by targeting a protein called BCMA on the surface of myeloma cells and delivering a cell-killing agent directly into those cells.
The most frequently reported side effects include eye problems (blurred vision, corneal changes, dry eyes, light sensitivity), infections such as COVID-19 and pneumonia, low blood cell counts (thrombocytopenia, neutropenia, anaemia), fatigue, nausea, diarrhoea, constipation, neuropathy (nerve damage), and musculoskeletal pain. Eye-related side effects are among the most characteristic and require regular ophthalmological monitoring throughout treatment.
Blenrep can cause changes to the corneal epithelium (the outer layer of the eye's surface) that may lead to blurred vision, dry eyes, and photophobia. These changes can sometimes occur without any noticeable symptoms, which is why professional eye examinations are required before each of the first four doses. Your ophthalmologist will use specialised examinations to detect early corneal changes so that dose adjustments can be made if necessary. Preservative-free lubricating eye drops must also be used at least four times daily during treatment.
Blenrep is given as an intravenous (IV) infusion over approximately 30 minutes by trained healthcare professionals in a hospital or clinic. The dose is calculated based on your body weight. You will not administer this medicine yourself at home. Treatment continues for as long as your doctor determines it is beneficial and tolerable, and the dosing schedule depends on whether you are receiving the BVd regimen (every 3 weeks) or the BPd regimen (every 4 weeks).
In general, you should not wear contact lenses while being treated with Blenrep. The medicine can cause changes to the corneal surface and dry eyes, and contact lenses may exacerbate these effects. Only use contact lenses if your ophthalmologist specifically advises that it is safe to do so. Instead, use preservative-free artificial tears at least four times daily to keep your eyes well lubricated throughout your treatment course.
If you notice any changes in your vision — including blurred vision, dry eyes, light sensitivity, or difficulty seeing — inform your doctor immediately. Your doctor may need to reduce your dose, extend the time between doses, or arrange an additional ophthalmological examination. Do not wait until your next scheduled appointment to report visual symptoms, as early intervention can help prevent more serious eye complications.
References
- European Medicines Agency (EMA). Blenrep (belantamab mafodotin) — Summary of Product Characteristics. EMA. Available at: www.ema.europa.eu. Accessed January 2026.
- Lonial S, Lee HC, Badros A, et al. Belantamab mafodotin for relapsed or refractory multiple myeloma (DREAMM-2): a two-arm, randomised, open-label, phase 2 study. Lancet Oncol. 2020;21(2):207–221. doi:10.1016/S1470-2045(19)30788-0
- Dimopoulos MA, Hungria VTM, Radinoff A, et al. Belantamab mafodotin, bortezomib, and dexamethasone for multiple myeloma (DREAMM-7): a phase 3, open-label, randomised trial. Lancet. 2024;403(10427):529–539. doi:10.1016/S0140-6736(23)02343-7
- National Comprehensive Cancer Network (NCCN). NCCN Clinical Practice Guidelines in Oncology: Multiple Myeloma. Version 3.2025. Available at: www.nccn.org.
- Dimopoulos MA, Moreau P, Terpos E, et al. Multiple myeloma: EHA-ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up. Ann Oncol. 2021;32(3):309–322. doi:10.1016/j.annonc.2020.11.014
- World Health Organization (WHO). WHO Model List of Essential Medicines — 23rd List (2023). Geneva: World Health Organization; 2023.
- British National Formulary (BNF). Belantamab mafodotin. NICE. Available at: bnf.nice.org.uk. Accessed January 2026.
- Farooq AV, Degli Esposti S, Popat R, et al. Corneal epithelial findings in patients with multiple myeloma treated with antibody–drug conjugate belantamab mafodotin in the pivotal, randomised, DREAMM-2 study. Ophthalmol Ther. 2020;9:889–911. doi:10.1007/s40123-020-00280-2
About Our Medical Editorial Team
This article was written and reviewed by the iMedic Medical Editorial Team, comprising licensed specialist physicians in oncology, haematology, and clinical pharmacology. Our editorial process follows strict medical standards:
All medical claims are supported by peer-reviewed research, clinical guidelines, and official prescribing information (EMA SmPC, FDA PI). Evidence level 1A where available.
Content is reviewed by board-certified oncologists and haematologists following the GRADE evidence framework and international guidelines from EMA, FDA, NCCN, and ESMO.
iMedic is independently funded with no pharmaceutical company sponsorship. Our editorial decisions are free from commercial influence.
This article is reviewed and updated regularly to reflect the latest clinical evidence, safety data, and regulatory decisions. Last reviewed: January 2026.