Increlex — mecasermin

Mecasermin is human insulin-like growth factor-1 (IGF-1) manufactured by recombinant DNA technology (rhIGF-1). IGF-1 is the primary mediator of the growth promoting effects of human growth hormone. As such, mecasermin also can stimulate the growth of bone, muscle, and internal organs. Its effects on skeletal muscle are also strongly hyperplasic, meaning it causes an increase in cell number. Unlike hGH, however, mecasermin has very strong insulin-like effects. It can support growth by increasing the uptake of amino acids, glucose, and fatty acids, but lowers blood sugar levels so efficiently that it can induce severe hypoglycemia if too high a dosage is taken. The increased uptake of fatty acids also means that mecasermin may promote lipogenesis, or an increase in the storage of body fat.This agent is of interest to bodybuilders and athletes for its potential to support the growth of skeletal muscle and connective tissue. Mecasermin is most commonly prescribed for the treatment of severe primary IGF-1 deficiency (Primary IGFD). This disease is characterized by a failure to produce normal levels of IGF-1 due to insufficiencies in the growth hormone / IGF-1 axis (usually involving GH receptor, signaling pathway, or IGF-1 gene defects). Such patients typically have normal or even high levels of growth hormone, but their bodies do not respond to it with the sufficient production of IGF-1. Mecasermin may also be used for the treatment of patients who have developed antibodies to growth hormone therapy. In both instances the patient is not GH deficient, but does not respond properly to growth hormone therapy, making IGF-1 an effective alternative medication. Given its differing effects on metabolism, however, mecasermin is not considered to be a medical substitute for hGH therapy, and retains a narrow field of FDA approved uses.

Brand name Increlex, Mecasermin

Mecasermin History

The U.S. Food and Drug Administration approved Mecasermin in August 2005. It is sold under the brand name Increlex, manufactured by Tercica Inc. of Brisbane ,California. Tercica licenses this technology from Genentech, which was the first company to sell a synthetically manufactured human growth hormone product in the United States (Protropin). Tercica’s rhIGF-1 is produced by a similar recombinant DNA technology. The process involves inserting the gene encoding for the human IGF-1 protein into E. coli bacteria, which then synthesize the protein. In October 2006, Tercia licensed the European rights to Increlex to the specialties pharmaceutical firm Ipsen. Ipsen received approval to market Increlex in the European Union in August 2007.

How is Mecasermin Supplied

Mecasermin (Increlex) is supplied in 4mL multi-dose vials containing 10 mg/mL.

Structural Characteristics of Mecasermin

Mecasermin is human IGF-1 protein manufactured by recombinant DNA technology. It consists of a string of 70 amino acids and has a molecular weight of 7,649 daltons. Its amino acid sequence is identical to that of endogenous human IGF-1.

Mecasermin Storage

Do not freeze. Refrigeration (2º to 8ºC, 35º to 46º F) required before and after reconstitution.

Mecasermin Side Effects (Hypoglycemia)

The most common adverse reaction to mecasermin therapy is hypoglycemia, which occurred on at least one occasion in 42% of patients receiving the drug during clinical trials. Approximately 7% of patients noticed severe hypoglycemia, and 5% noticed hypoglycemic seizure or loss of consciousness. Signs of mild to moderate hypoglycemia include hunger, drowsiness, blurred vision, depressive mood, dizziness, sweating, palpitation, tremor, restlessness, tingling in the hands, feet, lips, or tongue, lightheadedness, inability to concentrate, headache, sleep disturbances, anxiety, slurred speech, irritability, abnormal behavior, unsteady movement, and personality changes. If any of these warning signs should occur, one should immediately consume a food or drink containing simple sugars such as a candy bar or carbohydrate drink. Signs of severe hypoglycemia include disorientation, seizure, and unconsciousness. Severe hypoglycemia can lead to death and requires immediate emergency medical attention. Note that in some cases the symptoms of hypoglycemia can be mistaken for drunkenness.

Mecasermin should never be taken before sleep or in higher than recommended doses. A meal or snack must be consumed within 20 minutes (before or after) of administration.

Mecasermin Side Effects (Injection site)

The subcutaneous administration of mecasermin may cause bruising at the site of injection. It may also cause a localized increase of adipose tissue, which may be compounded by the repeated administration at the same site of injection. Rotation of the injection sites is recommended.

Mecasermin Side Effects (General)

Other potential adverse reactions to mecasermin therapy include joint pain, growth of the tonsils, snoring, headache, dizziness, convulsions, vomiting, ear pain, hearing loss, and hypertrophy of the thymus gland. Mild elevations in serum AST, ALT, and LDH levels were found in a significant number of patients, but they were not associated with hepatotoxicity. Mecasermin can stimulate the growth of internal organs. Kidney and spleen hypertrophy was particularly pronounced in the first years of long-term therapy in clinical trials, without declining renal function. Elevations in cholesterol and triglycerides were also observed, but remained within the upper limit of normal values. Evidence of heart enlargement was observed in a few patients, but this appeared without any apparent clinical significance. The overall relationship between mecasermin use and cardiac changes has not yet been fully assessed. Thickening of facial soft tissues was observed in several patients, and should be monitored during therapy. The abuse of mecasermin may cause acromegaly, which is characterized by a visible thickening of the bones, most notably the feet, forehead, hands, jaw, and elbows. Due to the growth promotion effects of hIGF-1, this drug should not be used by individuals with active or recurring cancer.

Mecasermin Administration

Mecasermin is intended for subcutaneous administration. The initiation of therapy involves close monitoring of blood glucose levels until a proper maintenance dose is established. The recommended starting dose is .04 to .08 mg/kg (40 to 80 mcg/kg) twice daily. The dose may be increased by .04 mg/kg per injection, reaching a maximum of .12 mg/kg twice daily. Doses greater than .12 mg/kg are not advised due to potential hypoglycemic effects. Mecasermin should always be administered within 20 minutes (before or after) a meal or snack.

Mecasermin is not widely used for physique- or performance-enhancing purposes. Common protocols of administration have not yet been established. Due to the potential for severe hypoglycemia, maximum doses among bodybuilders and athletes are not likely to measurably exceed those supplied by therapeutic guidelines. This drug will most likely by taken in cycles lasting no longer than 8-12 weeks in an effort to minimize unwanted organ growth or fat gain.

Mecasermin Availability

Mecasermin is approved for sale in the United States and Europe under the Increlex brand name.


Wlliam Llewellyn (2011) - Anabolics

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