IPLEX
Clinical safety rating
cautionComprehensive 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. |
| Molecular Weight | 7649 |
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 | Avoid due to potential anabolic effects on fetal growth; limited human data. |
| 2nd trimester | Avoid unless benefit outweighs risk; may affect fetal IGF-1 levels. |
| 3rd trimester | Avoid in late pregnancy due to potential effects on fetal growth and development. |
Clinical note
Comprehensive clinical and safety monograph for IPLEX (IPLEX).
| Placental transfer | Limited data; IGF-1 is known to cross the placenta, but the complex form may reduce transfer. However, potential for fetal effects exists. |
| Breastfeeding | IPLEX (mecasermin rinfabate) is a recombinant human insulin-like growth factor-1 (rhIGF-1) complexed with IGF binding protein-3. It is unknown if it is excreted in human milk. Given the molecular weight and potential for growth promotion in the infant, caution is advised. Use during breastfeeding is generally avoided unless no safer alternative exists. |
| Lactation Rating | L4 (Possibly Hazardous) |
| 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. |
| 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. |
■ FDA Black Box Warning
Not available (no FDA boxed warning as of current labeling).
| Serious Effects |
Active or suspected malignancyHypersensitivity to mecasermin or any componentEpiphyseal closure (linear growth stimulation not indicated)
| 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. |
| Food/Dietary | No specific food interactions reported. However, to minimize hypoglycemia risk, IPLEX should be administered immediately after a meal or snack. Avoid prolonged fasting. Alcohol use may increase hypoglycemia risk; avoid or limit alcohol consumption. |
| Clinical Pearls | IPLEX (mecasermin rinfabate) is a complex of recombinant human insulin-like growth factor-1 (rhIGF-1) and its binding protein (rhIGFBP-3). It is indicated for growth failure in children with severe primary IGF-1 deficiency (e.g., Laron syndrome) or with GH gene deletion who have developed neutralizing antibodies to GH. Administer subcutaneously; dose is based on IGF-1 levels. Monitor for hypoglycemia, especially after injection; patients should eat shortly after dosing. Do not use in patients with closed epiphyses or active neoplasia. May cause lymphoproliferative disorders; monitor for splenomegaly, lymphadenopathy. |
| Patient Advice | Inject IPLEX within 20 minutes after a meal or snack to prevent hypoglycemia. · Rotate injection sites (abdomen, thigh, upper arm) to avoid lipohypertrophy. · Report symptoms of hypoglycemia (shakiness, sweating, confusion) or increased growth velocity. · Keep a log of blood glucose levels if advised by your doctor. · Store IPLEX in the refrigerator (2-8°C); do not freeze. Protect from light. · Do not share needles or pens; dispose of used needles in a sharps container. · Continue regular follow-up appointments for growth monitoring and blood tests. |
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