Mecasermin (Increlex) - Recombinant IGF-1 for Growth Hormone Insensitivity — Aging
FDA-approved recombinant human IGF-1 for severe primary IGF-1 deficiency and growth hormone insensitivity syndrome.
Overview
Mecasermin (Increlex) is recombinant human insulin-like growth factor-1 (rhIGF-1) approved by the FDA in August 2005 for long-term treatment of growth failure in children ≥2 years with severe primary IGF-1 deficiency (primary IGFD) or GH gene deletion with neutralizing antibodies to GH. It bypasses the defective GH receptor pathway by directly providing IGF-1, which stimulates statural growth, glucose/lipid/amino acid uptake, and anabolic signaling. Pivotal trials showed height velocity increased from 2.8→8.0 cm/yr in year 1, with sustained growth for up to 8 years. This is a prescription medication requiring physician supervision due to hypoglycemia risk and other side effects.
Indications
- Severe primary IGF-1 deficiency (primary IGFD)
- GH gene deletion with neutralizing GH antibodies
- Growth hormone insensitivity syndrome (Laron syndrome)
- Growth failure in children ≥2 years
Mechanism of Action
Primary IGF-1 deficiency due to GH receptor mutations, GH gene deletion, or neutralizing GH antibodies prevents endogenous IGF-1 production
Dosing
| Compound | Dose | Frequency | Notes |
|---|---|---|---|
| Mecasermin 10 mg/mL solution | 0.04-0.08 mg/kg SC | Twice daily (20 min before/after meal) | Initial dose for children ≥2 years with severe primary IGFD |
| Mecasermin 10 mg/mL solution | Up to 0.12 mg/kg SC (maximum) | Twice daily | Titrate by 0.04 mg/kg/dose after 1 week if tolerated; rotate injection sites (arm, thigh, abdomen, buttock) |
Evidence Grade
GRADE B
Safety & Contraindications
- ⚠️ PRESCRIPTION MEDICATION - Physician supervision required
- HYPOGLYCEMIA RISK (42%): Must eat 20 min before/after dose; avoid fasting
- Adeno-tonsillar hypertrophy: May require tonsillectomy/adenoidectomy
- Intracranial hypertension: Monitor for headaches, visual changes, papilledema
- Organ enlargement: Kidney/spleen size monitoring required; renal function usually normal
- Antibody formation: 14/23 patients developed anti-IGF-1 antibodies (usually no clinical consequence)
- NOT for secondary IGF-1 deficiency (GH deficiency, malnutrition, hypothyroidism, steroid use)
- Theoretical cancer risk: IGF-1 has anti-apoptotic effects; long-term surveillance recommended
- Contraindicated: Active malignancy, closed epiphyses, IV use