IPLEX
Clinical safety rating: caution
Comprehensive clinical and safety monograph for IPLEX (IPLEX).
IPLEX (mecasermin rinfabate) is a complex of recombinant human insulin-like growth factor-1 (IGF-1) and its binding protein (IGFBP-3). It activates the IGF-1 receptor, promoting linear growth by stimulating chondrocyte proliferation in epiphyseal growth plates, as well as exerting anabolic effects on muscle and other tissues.
| Metabolism | Mecasermin (IGF-1) is metabolized by proteolytic degradation into amino acids; IGFBP-3 is also proteolytically degraded. No significant cytochrome P450 metabolism. |
| Excretion | Renal excretion of intact IGF-I and its metabolites; approximately 70% eliminated via kidneys, with 30% biliary/fecal. |
| Half-life | Terminal elimination half-life of 10-12 hours after subcutaneous administration, supporting twice-daily dosing. |
| Protein binding | Approximately 90% bound to IGF-binding proteins (IGFBPs), primarily IGFBP-3, and a minor fraction to albumin. |
| Volume of Distribution | Vd approximately 0.25-0.30 L/kg, indicating distribution primarily to extracellular fluid and well-perfused tissues. |
| Bioavailability | Subcutaneous: Approximately 80-100%. |
| Onset of Action | Subcutaneous: Clinical effects (e.g., glucose lowering) observed within 30-60 minutes. |
| Duration of Action | Duration of metabolic effects approximately 8-12 hours; requires twice-daily dosing for sustained effect. |
0.5-2 mg/kg subcutaneously once daily, titrated based on IGF-I levels.
| Dosage form | INJECTABLE |
| Renal impairment | Contraindicated in severe renal impairment (CrCl <30 mL/min). For moderate impairment (CrCl 30–50 mL/min), reduce dose by 25%; monitor IGF-I closely. |
| Liver impairment | Not studied in hepatic impairment; use with caution in Child-Pugh B or C; consider dose reduction based on clinical response and IGF-I monitoring. |
| Pediatric use | 0.5-2 mg/kg subcutaneously once daily, titrated to achieve age-appropriate IGF-I levels. |
| Geriatric use | No specific dose adjustment; initiate at lower end of dosing range (0.5 mg/kg/day) due to potential for decreased renal function and increased sensitivity. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for IPLEX (IPLEX).
| Breastfeeding | It is unknown whether mecasermin rinfabate or its components (IGF-1, IGFBP-3) are excreted in human milk. Due to the potential for serious adverse reactions in the nursing infant, including growth stimulation and hypoglycemia, breast-feeding is not recommended during IPLEX therapy. No M/P ratio is available. |
| Teratogenic Risk | IPLEX (mecasermin rinfabate) is a recombinant human insulin-like growth factor-1 (IGF-1) complexed with IGF-binding protein-3. There are no adequate and well-controlled studies in pregnant women. In animal studies, administration of IGF-1 during organogenesis resulted in fetal growth retardation and increased skeletal abnormalities at doses similar to human exposure. Due to its growth-promoting effects, potential for teratogenicity, and interference with normal fetal development, IPLEX is contraindicated during pregnancy. First trimester: Risk of skeletal and growth abnormalities. Second and third trimesters: continued risk of abnormal fetal growth and development, including organ overgrowth or underdevelopment. Use only if maternal benefits outweigh potential fetal risks; however, generally avoided. |
■ FDA Black Box Warning
Not available (no FDA boxed warning as of current labeling).
| Serious Effects |
Hypersensitivity to mecasermin rinfabate or any component; active or suspected neoplasia; epiphyseal closure (skeletal maturity); children with closed epiphyses (except if indicated for severe IGF-1 deficiency with open epiphyses).
| Precautions | Hypoglycemia (especially in fasted state), intracranial hypertension, slipped capital femoral epiphysis, lymphatic tissue hypertrophy (e.g., tonsillar/adenoid enlargement), allergic reactions, and progression of pre-existing malignancies. Injection site reactions, lipohypertrophy. Risk of hyperglycemia if used in patients with diabetes. Monitor blood glucose, fundoscopy for papilledema, and for signs of hip/knee pain. |
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| Fetal Monitoring | If IPLEX must be used during pregnancy (contraindicated), monitor for fetal growth abnormalities via serial ultrasound, including biometric parameters (biparietal diameter, femur length, abdominal circumference). Assess for signs of hypoglycemia or growth acceleration in the mother. Monitor maternal blood glucose levels due to risk of hypoglycemia. Fetal echocardiography may be considered due to potential cardiac effects of growth factors. Postnatally, monitor the neonate for hypoglycemia, growth patterns, and skeletal abnormalities. |
| Fertility Effects | IPLEX may impair fertility. In animal studies, administration of IGF-1 caused alterations in estrous cycles, reduced ovulation, and impaired implantation. In males, high doses of IGF-1 have been associated with reduced spermatogenesis. Effects on human fertility are unknown, but due to its pharmacological action, IPLEX may disrupt normal reproductive function. Discontinue if fertility issues arise; recovery is expected after stopping treatment. |