Mecasermin
Recombinant human IGF-1, approved for severe primary IGF-1 deficiency and growth failure that GH cannot treat. It bypasses the GH axis by supplying IGF-1 directly, promoting linear growth in children.
01 Overview
Mecasermin (brand Increlex) is recombinant human insulin-like growth factor 1 (rhIGF-1), the downstream effector of growth hormone. It is used in children with severe primary IGF-1 deficiency, GH gene deletion with neutralising antibodies, or Laron syndrome, where GH therapy is ineffective.
Because IGF-1 shares structural and functional overlap with insulin, hypoglycaemia is the key dose-limiting effect and dosing is tied to meals. It is a genuine FDA/EMA-approved biologic with a solid pediatric evidence base.
02 Mechanism
Directly activates the IGF-1 receptor, driving cellular growth and anabolism independent of the pituitary GH signal.
03 Dosing
| Tier | Dose | Route | Notes |
|---|---|---|---|
| Pediatric growth | 0.04–0.12 mg/kg | SubQ | Twice daily with or shortly before food to limit hypoglycaemia; titrated. |
04 Effects
| Effect | Magnitude | Evidence | |
|---|---|---|---|
| Increased linear growthImproves height velocity in severe primary IGF-1 deficiency. | +~8 cm/yr early | Clinical | |
| Anabolic/tissue growthPromotes growth in bone, muscle and organs via IGF-1 receptor. | dose-dependent | Clinical |
05 Side effects
| Effect | Severity | Frequency | Evidence | Countermeasures |
|---|---|---|---|---|
| HypoglycaemiaIGF-1's insulin-like activity can cause significant hypoglycaemia. | Severe | Common | Clinical | |
| Tonsillar/adenoid hypertrophyLymphoid tissue overgrowth can cause snoring or sleep apnoea. | Moderate | Common | Clinical | |
| Intracranial hypertensionRare raised intracranial pressure, typically early in therapy. | Severe | Rare | Clinical |