Bispecific gp100 × CD3 (ImmTAC) Pregnancy: Based on the mechanism of action, tebentafusp may cause fetal harm when administered to a pregnant woman. There are no available data in pregnant women and no animal reproductive or developmental toxicity studies have been conducted; molecules of similar molecular weight can cross the placenta resulting in fetal exposure. Advise women of the potential risk to the fetus and to use effective contraception (§8.1, §5.4).

Tebentafusp (Specialist drug)

Brand names: Kimmtrak

Tebentafusp is a bispecific T-cell engager used in HLA-A*02:01-positive adults with unresectable or metastatic uveal melanoma.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: 20 mcg (micrograms) on Day 1, 30 mcg on Day 8, 68 mcg on Day 15, then 68 mcg once every week thereafter.

Route: Intravenous infusion over 15-20 minutes, after dilution (2-step dilution using Albumin (Human) in 0.9% sodium chloride injection to prevent adsorption to the infusion bag and delivery system).

Frequency: Weekly. Treat until unacceptable toxicity or disease progression occurs.

Patient selection: only for unresectable or metastatic uveal melanoma in patients with a positive HLA-A*02:01 genotyping test on a whole blood sample (§2.1). Administer the first three infusions in an appropriate healthcare setting and monitor patients during the infusion and for at least 16 hours after it is complete. If the patient does not experience Grade 2 or worse hypotension (requiring medical intervention) during or after the third infusion, subsequent doses may be given in an appropriate ambulatory care setting with a minimum of 30 minutes monitoring after each infusion. No dosage reduction is recommended (§2.3); manage adverse reactions by withholding, resuming at the same dose level, or permanently discontinuing per US label Table 1 — during initial dose escalation do not escalate after a severe event, and resume escalation once the dosage is tolerated. Paediatric: safety and efficacy have not been established in paediatric patients (§8.4). Geriatric: no overall differences in safety or efficacy in patients 65 years and older (§8.5). Source note: no UK SPC (eMC) record was fetched — regimen taken from the US prescribing information, and the fetched §2 text was truncated at the source-fetch limit part-way through the preparation instructions.

Dose auto-extracted from US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

None (US label §4)

Side effects

Cytokine release syndrome
Rash
Pyrexia
Pruritus
Fatigue
Nausea
Chills

Clinical monograph

How it works

It combines an affinity-enhanced T-cell receptor that recognises a gp100 peptide presented on HLA-A*02:01 with an anti-CD3 effector, redirecting T cells to kill gp100-expressing uveal melanoma cells.

Prescribing in practice

Eligibility requires HLA-A*02:01 positivity, and cytokine release syndrome is common, so the first infusions are given with a step-up schedule under monitoring in a setting able to manage acute reactions.
Skin reactions related to gp100 expression in melanocytes are frequent.
Given by intravenous infusion by specialists with monitoring for hypotension and other features of cytokine release.

Monitoring

Monitor for cytokine release syndrome (including blood pressure) during and after early infusions and for skin reactions.

Counselling the patient

Report fever, rash, dizziness, or feeling faint during or after infusions.
Expect skin changes such as rash, itching or swelling, particularly early in treatment.
Attend the extended monitoring after your first infusions as arranged.

Evidence & guidelines

A randomised phase 3 trial demonstrated an overall survival benefit in metastatic uveal melanoma, supporting its approval.

Reference: NICE TA864; SmPC; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

Calculators

Pathways