Pegvisomant
Aliases: Somavert
Last verified: 2026-09-23
The short version
A PEGylated GH-receptor antagonist — the only drug that directly blocks growth-hormone action; for acromegaly.
Identity & type
- Molecular type
- analog
- Origin
- A PEGylated GH-receptor antagonist — the only drug that directly blocks growth-hormone action; for acromegaly.
Mechanism of action
Competitive GHR blockade → IGF-1 fall without tumor effect.
Dosing & routes
Official / clinical context
Approved drug — indications, dosing and warnings are defined by the official label. 10–30 mg SC daily.
Regulator-approved labeling and published study designs — never a recommendation.
Community-reported practice
10–30 mg SC daily. Somavert: in acromegaly normalizes IGF-1 in most patients when other drugs fall short; liver monitoring required.
Unverified self-reports. Not medical advice. Not endorsement.
Expected effects (community)
Somavert: in acromegaly normalizes IGF-1 in most patients when other drugs fall short; liver monitoring required.
Protocol — official vs community
Official / label
Somavert (acromegaly, inadequate response to surgery/radiation/somatostatin analogs): 40 mg loading dose SC, then 10 mg SC once daily; adjust in 5 mg steps by IGF-1 to a usual range of 10–30 mg/day.
- 01Day 1: 40 mg loading SC
- 02Maintenance: 10 mg SC daily; adjust by IGF-1 in 5 mg steps (usual 10–30 mg/day)
Duration: Chronic. Normalizes IGF-1 in >90% of patients in trials — the most complete biochemical control of any acromegaly drug.
It blocks the GH receptor rather than suppressing secretion, so tumor-size monitoring remains necessary — adenoma growth is a labeled warning. Liver enzymes need periodic checks.
Community (anecdotal)
Structured protocol data for this entry is coming.
Human evidence
Normalizes IGF-1 in >90% of patients.
Preclinical evidence
The preclinical phase was completed and submitted to regulators as part of registration; pharmacology and toxicology details are part of the official label.
Known risks
- Liver-enzyme elevation, adenoma growth (monitoring).characterized
Teal: characterized in clinical/labeling contexts. Amber: theoretical or reported outside controlled settings.
Unknowns & evidence gaps
- Real-world data outside controlled trials