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Kimmtrak Side Effects

Generic name: tebentafusp

Medically reviewed by Last updated on Nov 27, 2022.

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

Applies to tebentafusp: intravenous solution.


Intravenous route (Solution)

Warning: Cytokine Release SyndromeCytokine Release Syndrome (CRS), which may be serious or life-threatening, occurred in patients receiving tebentafusp-tebn. Monitor for at least 16 hours following first three infusions and then as clinically indicated.

Serious side effects of Kimmtrak

Along with its needed effects, tebentafusp (the active ingredient contained in Kimmtrak) 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 tebentafusp:

More common

  • Blurred vision
  • chills
  • confusion
  • diarrhea
  • dizziness
  • dizziness, faintness, or lightheadedness when getting up suddenly from a lying or sitting position
  • faintness
  • fast, pounding, or irregular heartbeat or pulse
  • feeling of warmth
  • fever
  • general feeling of discomfort or illness
  • headache
  • muscle or joint pain
  • nausea
  • nervousness
  • pounding in the ears
  • rash, itching, or skin swelling
  • redness of the face, neck, arms and occasionally, upper chest
  • redness of the skin
  • sweating
  • unusual tiredness or weakness
  • unusually warm skin
  • vomiting


  • Anxiety
  • chest pain
  • clay colored stools
  • cough
  • dark urine
  • loss of appetite
  • problems with movement, walking, or speech
  • seizures
  • stomach pain or tenderness
  • swelling of the feet or lower legs
  • trouble breathing
  • yellow eyes or skin

Other side effects of Kimmtrak

Some side effects of tebentafusp 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
  • burning, crawling, itching, numbness, prickling, "pins and needles", or tingling feelings
  • constipation
  • difficulty in moving
  • dry skin
  • joint pain or swelling
  • lightening of the normal skin color
  • loss or thinning of the hair
  • muscle aches, cramps, pain, or stiffness
  • night sweats
  • pain in the arms or legs
  • runny nose
  • shivering
  • sore throat
  • trouble sleeping

For Healthcare Professionals

Applies to tebentafusp: intravenous solution.


Serious side effects were reported in 28% of patients who received this drug and included cytokine release syndrome (CRS), rash, pyrexia, and hypotension. Side effects led to permanent discontinuation in 3.3% of patients and included anaphylactic reaction, brain edema, CRS, fatigue, hepatotoxicity, hypotension, and nausea. Side effects led to dosage interruption in 25% of patients and included fatigue, increased lipase, pyrexia, increased ALT, and increased AST. Side effects led to dose reduction in 5% of patients and included CRS and rash.

The most common side effects were CRS, rash, pyrexia, pruritus, fatigue, nausea, chills, abdominal pain, edema, hypotension, dry skin, headache, and vomiting; the most common laboratory abnormalities were decreased lymphocyte count, increased creatinine, increased glucose, increased AST, increased ALT, decreased hemoglobin, and decreased phosphate.[Ref]


Very common (10% or more): CRS (up to 89%), anti-drug antibodies (up to 33%)[Ref]

In 1 study, CRS (at least grade 2) occurred in 77% of patients treated with this drug; among these patients, 23%, 8%, and 0.8% received systemic corticosteroids, supplemental oxygen, and a vasopressor, respectively, for or during at least 1 infusion. In 1 study, 60% of patients had at least grade 2 CRS with more than 1 infusion (median of 2 events [range: 1 to 12 events]); most (84%) episodes of CRS started the day of infusion, and among cases that resolved, the median time to resolution was 2 days.[Ref]


Decreased lymphocyte count (grades 1 to 4: 91%; grades 3 to 4: 56%), decreased hemoglobin (grades 1 to 4: 51%; grades 3 to 4: 0.8%), decreased platelet count (grades 1 to 4: 16%), and decreased neutrophil count (grades 1 to 4: 14%; grades 3 to 4: 2%) have been reported.[Ref]

Very common (10% or more): Decreased lymphocyte count (up to 91%), decreased hemoglobin (up to 51%), decreased platelet count (up to 16%), decreased neutrophil count (up to 14%)[Ref]


Increased creatinine (grades 1 to 4: 87%; grades 3 to 4: 0.4%) has been reported.[Ref]

Very common (10% or more): Increased creatinine (up to 87%)[Ref]


Very common (10% or more): Skin reactions (up to 91%), rash (up to 83%), pruritus (up to 69%), dry skin (up to 31%), skin hypopigmentation (up to 28%), cutaneous edema (up to 27%), erythema (up to 25%), hair color changes (up to 20%)

Frequency not reported: Alopecia, skin hyperpigmentation, night sweats[Ref]

In 1 study, skin reactions occurred in 91% of patients treated with this drug, including grade 2 (44%) and grade 3 (21%) events; skin reactions included rash (83%), pruritus (69%), erythema (25%), and cutaneous edema (27%). The median time to onset of skin reactions was 1 day (range: 1 to 55 days); the median time to improvement to grade 1 or lower was about 6 days.

Alopecia, skin hyperpigmentation, and night sweats were reported in less than 20% of patients.[Ref]


Decreased phosphate (grades 1 to 4: 51%; grades 3 to 4: 11%), decreased albumin (grades 1 to 4: 47%; grades 3 to 4: 2.1%), decreased calcium (grades 1 to 4: 45%; grades 3 to 4: 1.6%), decreased magnesium (grades 1 to 4: 34%), increased alkaline phosphatase (grades 1 to 4: 34%; grades 3 to 4: 2.9%), decreased sodium (grades 1 to 4: 30%; grades 3 to 4: 2.9%), increased potassium (grades 1 to 4: 29%; grades 3 to 4: 1.6%), decreased potassium (grades 1 to 4: 17%; grades 3 to 4: 0.8%), and increased calcium (grades 1 to 4: 13%) have been reported.

Flushing and influenza-like illness were reported in less than 20% of patients.[Ref]

Very common (10% or more): Pyrexia (up to 76%), fatigue (up to 64%), decreased phosphate (up to 51%), chills (up to 48%), decreased albumin (up to 47%), edema (up to 45%), decreased calcium (up to 45%), decreased magnesium (up to 34%), increased alkaline phosphatase (up to 34%), decreased sodium (up to 30%), increased potassium (up to 29%), decreased potassium (up to 17%), increased calcium (up to 13%)

Frequency not reported: Flushing, influenza-like illness[Ref]


Increased glucose (grades 1 to 4: 66%; grades 3 to 4: 3.3%) and decreased glucose (grades 1 to 4: 18%; grades 3 to 4: 0.4%) have been reported.

Decreased appetite was reported in less than 20% of patients.[Ref]

Very common (10% or more): Increased glucose (up to 66%), decreased glucose (up to 18%)

Frequency not reported: Decreased appetite[Ref]


Very common (10% or more): Increased ALT/AST (up to 65%), increased AST (up to 55%), increased ALT (up to 52%), increased bilirubin (up to 27%)

Common (1% to 10%): Liver enzyme elevations

Frequency not reported: Hepatotoxicity[Ref]

Increased AST (grades 1 to 4: 55%; grades 3 to 4: 13%), increased ALT (grades 1 to 4: 52%; grades 3 to 4: 9%), and increased bilirubin (grades 1 to 4: 27%; grades 3 to 4: 4.1%) have been reported.

In 1 study, increases in ALT and AST were observed in 65% of patients treated with this drug; in those with ALT/AST elevations, 73% initially occurred within the first 3 infusions. Most patients with grade 3 or 4 ALT/AST elevations had improvement to grade 1 or lower within 7 days. For events observed outside the setting of CRS, the median time to onset was 129 days; grade 3 or greater liver enzyme elevations outside the setting of CRS occurred in about 8% of patients. Liver enzyme elevations led to permanent discontinuation in 0.4% of patients.[Ref]


Increased lipase (grades 1 to 4: 37%; grades 3 to 4: 15%) and increased amylase (grades 1 to 4: 23%; grades 3 to 4: 4.1%) have been reported.

Constipation was reported in less than 20% of patients.[Ref]

Very common (10% or more): Nausea (up to 49%), abdominal pain (up to 45%), increased lipase (up to 37%), vomiting (up to 30%), diarrhea (up to 25%), increased amylase (up to 23%)

Frequency not reported: Constipation[Ref]


Hypertension and tachycardia/sinus tachycardia were reported in less than 20% of patients.[Ref]

Very common (10% or more): Hypotension (up to 39%)

Frequency not reported: Hypertension, tachycardia/sinus tachycardia[Ref]

Nervous system

Very common (10% or more): Headache (up to 31%)

Frequency not reported: Paresthesia, dizziness, brain edema[Ref]

Paresthesia and dizziness were reported in less than 20% of patients.[Ref]


Very common (10% or more): Arthralgia (up to 22%)

Frequency not reported: Back pain, muscle spasms, myalgia, pain in extremity[Ref]

Back pain, muscle spasms, myalgia, and pain in extremity were reported in less than 20% of patients.[Ref]


Frequency not reported: Anaphylactic reaction[Ref]


Frequency not reported: Dyspnea, oropharyngeal pain, pulmonary embolism[Ref]

Dyspnea and oropharyngeal pain were reported in less than 20% of patients.

A fatal pulmonary embolism occurred in 1 patient.[Ref]


1. Product Information. Kimmtrak (tebentafusp). Immunocore LLC. 2022.

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.