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Zynlonta Side Effects

Generic name: loncastuximab tesirine

Medically reviewed by Last updated on Sep 26, 2022.

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

Applies to loncastuximab tesirine: intravenous powder for solution.

Serious side effects of Zynlonta

Along with its needed effects, loncastuximab tesirine (the active ingredient contained in Zynlonta) 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 loncastuximab tesirine:

More common

  • Black, tarry stools
  • bleeding gums
  • blood in the urine or stools
  • body aches or pain
  • chills
  • cough
  • ear congestion
  • fever
  • headache
  • increased sensitivity of the skin to sunlight
  • itching, skin rash
  • loss of voice
  • lower back or side pain
  • muscle or bone pain
  • pain or tenderness around the eyes and cheekbones
  • painful or difficult urination
  • pale skin
  • pinpoint red spots on the skin
  • redness or other discoloration of the skin
  • severe sunburn
  • sore throat
  • stuffy or runny nose
  • swelling of the hands, ankles, feet, or lower legs
  • swelling or puffiness of the face
  • tightness in the chest
  • trouble breathing
  • ulcers, sores, or white spots in the mouth
  • unusual bleeding or bruising
  • unusual tiredness or weakness

Less common

  • Anxiety
  • blistering, crusting, irritation, itching, or reddening of the skin
  • blue or pale skin
  • chest pain, possibly moving to the left arm, neck, or shoulder
  • confusion
  • cracked, dry, scaly skin
  • darkening of the skin
  • dizziness
  • dry cough
  • fainting
  • fast heartbeat
  • general feeling of discomfort or illness
  • lightheadedness
  • rapid, shallow breathing
  • sneezing
  • thickening of bronchial secretions

Other side effects of Zynlonta

Some side effects of loncastuximab tesirine 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

  • Back pain
  • constipation
  • decreased appetite
  • diarrhea
  • difficulty in moving
  • joint pain
  • lack or loss of strength
  • muscle aches, cramps, or stiffness
  • nausea
  • stomach pain
  • swollen joints
  • unusual drowsiness, dullness, or feeling of sluggishness
  • vomiting

For Healthcare Professionals

Applies to loncastuximab tesirine: intravenous injection.


Very common (10% or more): Platelets decreased (58%), neutrophils decreased (52%), hemoglobin decreased (51%), albumin decreased (37%), neutropenia (Grade 3 or 4) (32%), thrombocytopenia (20%), anemia (12%)

Common (1% to 10%): Febrile neutropenia[Ref]


Common (1% to 10%): Sepsis/escherichia sepsis/septic shock

Frequency not reported: Immunogenicity[Ref]


Uncommon (0.1% to 1%): Infusion site extravasation[Ref]


Very common (10% or more): Musculoskeletal pain (e.g., musculoskeletal pain, musculoskeletal chest pain, musculoskeletal discomfort, back pain, limb discomfort, myalgia, neck pain, non-cardiac chest pain, pain in extremity) (23%)[Ref]


Very common (10% or more): Glucose increased (48%), edema (e.g., edema, face edema, generalized edema, peripheral edema, ascites, fluid overload, peripheral swelling, swelling, swelling face) (28%), anorexia (15%)[Ref]


Very common (10% or more): AST increased (37%), ALT increased (34%)[Ref]


Very common (10% or more): Dyspnea/dyspnea exertional (13%), pleural effusion (10%), upper respiratory tract infection (e.g., upper respiratory tract infection, upper respiratory tract congestion, nasopharyngitis, rhinitis, rhinovirus infection, sinusitis (10%)

Common (1% to 10%): Pleural effusion (Grade 3), pneumonia/pneumonitis, pleuritis[Ref]


Very common (10% or more): Fatigue/asthenia/lethargy (38%)[Ref]


The most common (greater than 20%) adverse reactions, including laboratory abnormalities, were thrombocytopenia, increased gamma-glutamyltransferase, neutropenia, anemia, hyperglycemia, transaminase elevation, fatigue, hypoalbuminemia, rash, edema, nausea, and musculoskeletal pain.[Ref]


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


Very common (10% or more): Rash (e.g., rash erythematous, rash maculopapular, rash pruritic, rash pustular, erythema, generalized erythema, dermatitis, dermatitis acneiform, dermatitis bullous, dermatitis exfoliative generalized, palmar-plantar erythrodysesthesia syndrome) (30%), pruritus (12%), photosensitivity reaction (10%)

Common (1% to 10%): Hyperpigmentation, dermatitis[Ref]


Very common (10% or more): Nausea (23%), diarrhea (17%), abdominal pain (e.g., abdominal pain, abdominal discomfort, abdominal pain lower, abdominal pain upper) (14%), vomiting (13%), constipation (12%)

Common (1% to 10%): Pericardial effusion[Ref]


1. "Product Information. Zynlonta (loncastuximab tesirine)." ADC Therapeutics America (2021):

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.