Somatrem

Summary

Somatrem (met-hGH) was the first recombinant human growth hormone analog approved by the FDA, marketed as Protropin by Genentech. It contains an extra methionine residue at the N-terminus compared to native hGH. It was indicated for treatment of growth failure in children due to growth hormone deficiency. It was withdrawn from the market in 2004 and replaced by somatropin (authentic sequence rhGH), which had a more favorable immunogenicity profile.

Mechanism of Action

Binds to growth hormone receptors on target cells, stimulating IGF-1 production in the liver and peripheral tissues, promoting linear bone growth, protein synthesis, lipolysis, and carbohydrate metabolism. Somatrem is a methionyl derivative of human growth hormone (met-hGH), differing by an additional N-terminal methionine residue.

Routes of Administration

Goals & Uses

• Increased lean body massBody CompositionModerate
• Reduction of body fatMetabolicModerate
• Treatment of pediatric growth hormone deficiencyEndocrinology / GrowthHigh

Contraindications

• Active malignancyOncologyHighUse caution or avoid depending on agent and context
• Closed epiphysesSkeletalModerate
• Hypersensitivity to somatrem or excipientsAllergy/ImmunologyHigh
• Diabetic retinopathyOphthalmologyModerate
• Prader-Willi syndrome with severe obesity or respiratory impairmentGenetic SyndromeHigh

Adverse Effects

• EdemaFluid BalanceUncommonSwelling from fluid retention
• Injection site reactionsLocalCommon
• Intracranial hypertensionNeurologicalUncommon
• Hyperglycemia / insulin resistanceMetabolic / EndocrineUncommon
• Slipped capital femoral epiphysisMusculoskeletalRare
• Antibody formation to somatremImmunologicalCommon

Drug Interactions

• Cytochrome P450-metabolized drugs (e.g., corticosteroids, sex steroids, anticonvulsants)Low
• GlucocorticoidsModerate
• Insulin / antidiabetic agentsModerate

Population Constraints

• Pediatric patientsAgeAbsolute
• Patients with diabetes mellitusMetabolicRelative
• Patients with hypothyroidismEndocrineRelative

Regulatory Status

• European UnionWithdrawnApproved: Pediatric growth hormone deficiencyNo longer marketed in EU; superseded by somatropin products with native GH sequence.
• United StatesWithdrawnApproved: Pediatric growth hormone deficiency with growth failureFDA approved 1985 (NDA 19-640); voluntarily withdrawn by Genentech in 2004. Replaced by somatropin (Nutropin).
• United KingdomWithdrawnApproved: Pediatric growth hormone deficiencyNo longer available; replaced by native-sequence recombinant hGH products.

FDA approved in 1985 as the first recombinant DNA-derived growth hormone; voluntarily withdrawn from the US market in 2004 by Genentech in favor of somatropin (Nutropin). Higher immunogenicity compared to native-sequence somatropin due to the additional methionine residue.

Evidence & Sources

No sources recorded yet.