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Blenrep Side Effects

Generic name: belantamab mafodotin

Medically reviewed by Last updated on Feb 15, 2023.

Note: This document contains side effect information about belantamab mafodotin. Some dosage forms listed on this page may not apply to the brand name Blenrep.

Applies to belantamab mafodotin: intravenous powder for solution.


Intravenous route (Powder for Solution)

Ocular ToxicityBelantamab mafodotin-blmf caused changes in the corneal epithelium resulting in changes in vision, including severe vision loss and corneal ulcer, and symptoms, such as blurred vision and dry eyes.Conduct ophthalmic exams at baseline, prior to each dose, and promptly for worsening symptoms. Withhold belantamab mafodotin-blmf until improvement and resume, or permanently discontinue, based on severity.Because of the risk of ocular toxicity, belantamab mafodotin-blmf is available only through a restricted program under a Risk Evaluation and Mitigation Strategy (REMS) called the BLENREP REMS.

Serious side effects of Blenrep

Along with its needed effects, belantamab mafodotin (the active ingredient contained in Blenrep) may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor or nurse immediately if any of the following side effects occur while taking belantamab mafodotin:

More common

  • Black, tarry stools
  • bleeding gums
  • blood in urine or stools
  • blurred vision or any other change in vision
  • body aches or pain
  • change in color vision
  • chest pain or tightness
  • chills
  • confusion
  • constipation
  • cough
  • decreased frequency or amount of urine
  • depression
  • difficulty seeing at night
  • difficulty with swallowing
  • dizziness
  • dry eye
  • dry mouth
  • ear congestion
  • eye redness, irritation, or pain
  • fainting
  • fast heartbeat
  • fever
  • headache
  • incoherent speech
  • increased sensitivity of the eyes to sunlight
  • increased thirst
  • increased urination
  • lightheadedness or faintness
  • loss of appetite
  • loss of voice
  • low blood pressure or pulse
  • lower back or side pain
  • metallic taste
  • muscle weakness
  • nausea
  • pinpoint red spots on the skin
  • pounding in the ears
  • rapid, shallow breathing
  • runny or stuffy nose
  • skin rash, itching, or hives
  • sneezing
  • sore throat
  • stomach pain
  • swelling in the face, hands, or lower legs
  • trouble breathing
  • unconsciousness
  • unusual bleeding or bruising
  • unusual tiredness or weakness
  • vomiting
  • weight gain or loss

Incidence not known

  • General feeling of discomfort or illness
  • thickening of bronchial secretions

Other side effects of Blenrep

Some side effects of belantamab mafodotin may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common

For Healthcare Professionals

Applies to belantamab mafodotin: intravenous powder for injection.


Very common (10% or more): Ocular adverse reactions (77%), keratopathy (based on slit lamp eye examination and characterized as corneal epithelium changes with or without symptoms) (76% all Grades; 44% Grade 3 or 4), decreased visual acuity (53% all Grades; 28% Grade 3 or 4), blurred vision (e.g., diplopia, vision blurred, visual acuity reduced, visual impairment (22% all Grades; 4% Grade 3 or 4), dry eye (e.g., dry eye, ocular discomfort, eye pruritus) (14% all Grades 1% Grade 3 or 4)

Common (1% to 10%): Photophobia, eye irritation, infective keratitis, ulcerative keratitis[Ref]


Very common (10% or more): Thrombocytopenia (69% all Grades, 13% Grade 2, 10% Grade 3, 17% Grade 4), platelets decreased (62%), lymphocytes decreased (49%), hemoglobin decreased (32%), neutrophils decreased (28%)[Ref]


Frequency not reported: Potential for immunogenicity[Ref]


Very common (10% or more): Infusion related reactions (IRRs) (e.g., infusion-related reaction, pyrexia, chills, diarrhea, nausea, asthenia, hypertension, lethargy, tachycardia) (21%)[Ref]


Very common (10% or more): Arthralgia (12%), back pain (11%)[Ref]


Very common (10% or more): Albumin decreased (43%), glucose increased (38%), sodium decreased (21%), potassium decreased (20%), anorexia (12%)[Ref]


Common (1% to 10%): Albuminuria[Ref]


Very common (10% or more): Aspartate aminotransferase increased (57%), alkaline phosphatase increased (26%), gamma-glutamyl transferase increased (25%)[Ref]


Very common (10% or more): Upper respiratory tract infection (e.g., upper respiratory tract infection, nasopharyngitis, rhinovirus infections, sinusitis (11%)

Common (1% to 10%): Pneumonia[Ref]


Very common (10% or more): Pyrexia (22%), fatigue/asthenia (20%)[Ref]


This drug caused serious adverse reactions in 40% of patients. Serious adverse reactions in 3% or more of patients included pneumonia (7%), pyrexia (6%), renal impairment (4%), sepsis (4%), hypercalcemia (4%), and infusion-related reactions (3%). Fatal adverse reactions occurred in 3.2% of patients, including sepsis (1%), cardiac arrest (1%), and lung infection (1%).[Ref]


Very common (10% or more): Creatinine increased/creatinine phosphokinase increased (22%)[Ref]


Very common (10% or more): Infusion related tachycardia[Ref]


Very common (10% or more): Nausea (24%), constipation (13%), diarrhea (13%)

Common (1% to 10%): Vomiting[Ref]


1. "Product Information. Blenrep (belantamab mafodotin)." GlaxoSmithKline (2020):

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.