Anti-IGF-1R monoclonal antibody Pregnancy: Should not be used in pregnancy — based on animal findings and its mechanism of action (inhibition of IGF-1 receptor signalling) it may cause fetal harm. Appropriate contraception should be implemented prior to initiation, during treatment and for 6 months following the last dose; women of childbearing age should have a pregnancy test before starting. If the patient becomes pregnant during treatment, discontinue and advise of the potential risk to the fetus.

Teprotumumab

Brand names: Tepezza

Teprotumumab is a monoclonal antibody used in the treatment of thyroid eye disease (thyroid-associated ophthalmopathy), reducing proptosis and orbital inflammation. It is given by intravenous infusion.

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: 10 mg/kg by intravenous infusion for the initial dose, followed by 20 mg/kg by intravenous infusion every 3 weeks for 7 additional infusions (8 infusions in total)

Route: Intravenous infusion — reconstitute each 500 mg vial with 10 mL sterile water for injection and dilute further in 0.9% sodium chloride injection; do not administer as an intravenous push or bolus

Frequency: Initial dose, then every 3 weeks for 7 further infusions

US label (Tepezza) — no UK SPC was fetched. Infusion duration: administer the diluted solution intravenously over at least 90 minutes for the first two infusions; if well tolerated, the minimum time for subsequent infusions can be reduced to 60 minutes; if not well tolerated, the minimum time for subsequent infusions should remain 90 minutes and pre-medication is recommended for subsequent infusions. Preparation: each vial contains 500 mg; after reconstitution the concentration is 47.6 mg/mL (10.5 mL total volume); use a 100 mL infusion bag for a dose less than 1800 mg and a 250 mL bag for a dose of 1800 mg or greater, removing an equivalent volume of sodium chloride first. Do not infuse concomitantly with other agents. Combined storage time of reconstituted and diluted solution is 4 hours at room temperature or up to 48 hours refrigerated, protected from light. Paediatric: safety and effectiveness have not been established in paediatric patients. Geriatric: no overall differences in efficacy or safety observed in patients 65 years and older.

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 (section 4 of the US label states: None)

Side effects

Muscle spasm (incidence greater than 5%)
Nausea and diarrhoea
Alopecia
Fatigue and headache
Hyperglycaemia (assess blood glucose before infusion and monitor during treatment)
Hearing impairment including hearing loss, which may be severe and in some cases permanent; dry skin, dysgeusia, weight decreased, nail disorder; infusion reactions in approximately 4% of patients

Clinical monograph

How it works

It is a fully human monoclonal antibody that binds and inhibits the insulin-like growth factor-1 receptor (IGF-1R), interrupting the signalling that drives orbital fibroblast activation and the tissue expansion seen in thyroid eye disease.

Prescribing in practice

It can cause or worsen hyperglycaemia, so blood glucose and glycaemic control should be assessed before and during treatment, particularly in patients with pre-existing diabetes.
Infusion-related reactions can occur, and pre-existing inflammatory bowel disease may be exacerbated, so patients should be monitored and the diagnosis confirmed before starting.
Hearing impairment, including some cases that may be persistent, has been reported, so auditory symptoms should be reviewed during therapy.

Monitoring

Monitor blood glucose, hearing, and ophthalmic response, and review symptoms suggestive of an infusion reaction or worsening inflammatory bowel disease throughout the treatment course.

Counselling the patient

Report any new or worsening high blood sugar symptoms such as excessive thirst or passing more urine.
Tell your clinician about any hearing changes, ringing in the ears, or new bowel symptoms.
Effective contraception is advised because of potential harm to a developing baby.

Evidence & guidelines

Efficacy in reducing proptosis in active thyroid eye disease was established in randomised placebo-controlled trials that underpinned its regulatory approval for this indication.

Reference: 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