1.1 Severe Primary IGF-1 Deficiency (Primary IGFD)

INCRELEX® (mecasermin [rDNA origin] injection) is indicated for the treatment of:

• growth failure in children with severe primary IGF-1 deficiency.
• growth hormone (GH) gene deletion who have developed neutralizing antibodies to GH.

Severe Primary IGF-1 deficiency (IGFD) is defined by:

• height standard deviation score ≤ –3.0 and
• basal IGF-1 standard deviation score ≤ –3.0 and
• normal or elevated growth hormone (GH).

Severe Primary IGFD includes classical and other forms of growth hormone insensitivity. Patients with Primary IGFD may have mutations in the GH receptor (GHR), post-GHR signaling pathway including the IGF-1 gene. They are not GH deficient, and therefore, they cannot be expected to respond adequately to exogenous GH treatment.

INCRELEX® is not intended for use in subjects with secondary forms of IGF-1 deficiency, such as GH deficiency, malnutrition, hypothyroidism, or chronic treatment with pharmacologic doses of anti-inflammatory steroids. Thyroid and nutritional deficiencies should be corrected before initiating INCRELEX® treatment.

Limitations of use: INCRELEX® is not a substitute to GH for approved GH indications.

2.1 Dosage

Preprandial glucose monitoring is recommended at treatment initiation and until a well-tolerated dose is established. If frequent symptoms of hypoglycemia or severe hypoglycemia occur, preprandial glucose monitoring should continue. The dosage of INCRELEX® should be individualized for each patient. The recommended starting dose of INCRELEX® is 0.04 to 0.08 mg/kg (40 to 80 micrograms/kg) twice daily by subcutaneous injection. If well-tolerated for at least one week, the dose may be increased by 0.04 mg/kg per dose, to the maximum dose of 0.12 mg/kg given twice daily. Doses greater than 0.12 mg/kg given twice daily have not been eva luated in children with Primary IGFD and, due to potential hypoglycemic effects, should not be used. If hypoglycemia occurs with recommended doses despite adequate food intake, the dose should be reduced. INCRELEX® should be administered shortly before or after (± 20 minutes) a meal or snack. If the patient is unable to eat shortly before or after a dose for any reason, that dose of INCRELEX® should be withheld. Subsequent doses of INCRELEX® should never be increased to make up for one or more omitted doses.

Treatment with INCRELEX should be supervised by a physician who is experienced in the diagnosis and management of pediatric patients with short stature associated with severe primary IGF-1 deficiency or with growth hormone gene deletion and who have developed neutralizing antibodies to growth hormone.

2.2 Administration

INCRELEX® is administered by subcutaneous injection.

INCRELEX® injection sites should be rotated to a different site (upper arm, thigh, buttock or abdomen) with each injection to help prevent lipohypertrophy.

INCRELEX® should be administered using sterile disposable syringes and needles. The syringes should be of small enough volume so that the prescribed dose can be withdrawn from the vial with accuracy.

Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration, whenever solution and container permit.

If using syringes that measure dose in units, doses in mg/kg must be converted to units using the following formula: Weight (kg) × Dose (mg/kg) × 1 mL/10 mg × 100 units/1 mL = units/injection.

• Active or Suspected Neoplasia

INCRELEX® is contraindicated in the presence of active or suspected malignancy, and therapy should be discontinued if evidence of malignancy develops.

• Known Hypersensitivity

INCRELEX® should not be used by patients who are allergic to mecasermin (rhIGF-1) or any of the inactive ingredients in INCRELEX®, or who have experienced a severe hypersensitivity to INCRELEX® [see Warnings and Precautions (5.2) and Adverse Reactions (6.3)]

• Intravenous Administration

Intravenous administration of INCRELEX® is contraindicated.

• Closed Epiphyses

INCRELEX® should not be used for growth promotion in patients with closed epiphyses.

5.1 Hypoglycemia

Because INCRELEX® has insulin-like hypoglycemic effects it should be administered shortly before or after (± 20 minutes) a meal or snack. Glucose monitoring and INCRELEX® dose titration are recommended until a well tolerated dose is established [see Dosage and Administration (2.1)] and subsequently as medically indicated. Special attention should be paid to small children because their oral intake may not be consistent. Patients should avoid engaging in any high-risk activities (e.g., driving, etc.) within 2 to 3 hours after dosing, particularly during the initiation of INCRELEX® treatment until tolerability and a stable dose have been established [see Adverse Reactions (6.1)]. INCRELEX® should not be administered when the meal or snack is omitted. The dose of INCRELEX® should never be increased to make up for one or more omitted doses.

5.2 Hypersensitivity and Allergic Reactions, including Anaphylaxis

Allergic reactions to INCRELEX® have been reported post-marketing. They range from localized (injection site) reactions to systemic reactions, including anaphylaxis requiring hospitalization. Parents and patients should be informed that such reactions are possible and that if a systemic allergic reaction occurs, treatment should be interrupted and prompt medical attention should be sought. [see Contraindications (4) and Adverse Reactions (6.3)]

5.3 Intracranial Hypertension

Intracranial hypertension (IH) with papilledema, visual changes, headache, nausea and/or vomiting have occurred in patients treated with INCRELEX®. IH-associated signs and symptoms resolved after interruption of dosing. Funduscopic examination is recommended at the initiation and periodically during the course of INCRELEX® therapy. [see Adverse Reactions (6.3)]

5.4 Lymphoid Tissue Hypertrophy

Lymphoid tissue (e.g., tonsillar and adenoidal) hypertrophy associated with complications, such as snoring, sleep apnea, and chronic middle-ear effusions have been reported with the use of INCRELEX®. Patients should have periodic examinations to rule out such potential complications and receive appropriate treatment if necessary. [see Adverse Reactions (6.3)]

5.5 Slipped Capital Femoral Epiphysis

Slipped capital femoral epiphysis can occur in patients who experience rapid growth. Any pediatric patient with the onset of a limp or complaints of hip or knee pain during INCRELEX® therapy should be carefully eva luated.

5.6 Progression of Preexisting Scoliosis

Progression of scoliosis may occur in patients who experience rapid growth. Because INCRELEX® increases growth rate, patients with a history of scoliosis who are treated with INCRELEX® should be monitored for progression of scoliosis.

5.7 Benzyl Alcohol

Benzyl alcohol, a component of this product, has been associated with serious adverse events and death, particularly in pediatric patients. The "gasping syndrome," (characterized by central nervous system depression, metabolic acidosis, gasping respirations, and high levels of benzyl alcohol and its metabolites found in the blood and urine) has been associated with benzyl alcohol dosages >99 mg/kg/day in neonates and low-birth weight neonates. Additional symptoms may include gradual neurological deterioration, seizures, intracranial hemorrhage, hematologic abnormalities, skin breakdown, hepatic and renal failure, hypotension, bradycardia, and cardiovascular collapse. Practitioners administering this and other medications containing benzyl alcohol should consider the combined daily metabolic load of benzyl alcohol from all sources.

6.1 Clinical Trial Experience

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.

In clinical studies of 71 subjects with Primary IGFD treated for a mean duration of 3.9 years and representing 274 subject-years, no subjects withdrew from any clinical study because of adverse reactions. Adverse reactions to INCRELEX® treatment that occurred in 5% or more of these study participants are listed below by organ class.

 

Metabolism and Nutrition Disorders: hypoglycemia

 

General Disorders and Administrative Site Conditions: lipohypertrophy, bruising

 

Infections and Infestations: otitis media, serous otitis media

 

Respiratory, Thoracic and Mediastinal Disorders: snoring, tonsillar hypertrophy

 

Nervous System Disorders: headache, dizziness, convulsions

 

Gastrointestinal Disorders: vomiting

 

Ear and Labyrinth Disorders: hypoacusis, fluid in middle ear, ear pain, abnormal tympanometry

 

Cardiac Disorders: cardiac murmur

 

Musculoskeletal and Connective Tissue Disorders: arthralgia, pain in extremity

 

Blood and Lymphatic System Disorders: thymus hypertrophy

 

Surgical and Medical Procedures: ear tube insertion

Hypoglycemia was reported by 30 subjects (42%) at least once during their course of therapy. Most cases of hypoglycemia were mild or moderate in severity. Five subjects had severe hypoglycemia (requiring assistance and treatment) on one or more occasions and 4 subjects experienced hypoglycemic seizures/loss of consciousness on one or more occasion. Of the 30 subjects reporting hypoglycemia, 14 (47%) had a history of hypoglycemia prior to treatment. The frequency of hypoglycemia was highest in the first month of treatment, and episodes were more frequent in younger children. Symptomatic hypoglycemia was generally avoided when a meal or snack was consumed either shortly (i.e., 20 minutes) before or after the administration of INCRELEX®.

Tonsillar hypertrophy was noted in 11 (15%) subjects in the first 1 to 2 years of therapy with lesser tonsillar growth in subsequent years. Tonsillectomy or tonsillectomy/adenoidectomy was performed in 7 subjects; 3 of these had obstructive sleep apnea, which resolved after the procedure in all three cases.

Intracranial hypertension occurred in three subjects. In two subjects the events resolved without interruption of INCRELEX® treatment. INCRELEX® treatment was discontinued in the third subject and resumed later at a lower dose without recurrence.

Mild elevations in the serum AST and LDH were found in a significant proportion of patients before and during treatment. Rise in levels of these serum enzymes did not lead to treatment discontinuation. ALT elevations were occasionally noted during treatment.

Renal and splenic lengths (measured by ultrasound) increased rapidly on INCRELEX® treatment during the first years of therapy. This lengthening slowed down subsequently; though in some patients, renal and/or splenic length reached or surpassed the 95th percentile. Renal function (as defined by serum creatinine and calculated creatinine clearance) was normal in all patients, irrespective of renal growth.

Elevations in cholesterol and triglycerides to above the upper limit of normal were observed before and during treatment.

Echocardiographic evidence of cardiomegaly/valvulopathy was observed in a few individuals without associated clinical symptoms. The relation of these cardiac changes to drug treatment cannot be assessed due to underlying disease and the lack of a control group.

Thickening of the soft tissues of the face was observed in several patients and should be monitored during INCRELEX® treatment.

6.2 Immunogenicity

As with all therapeutic proteins, there is potential for immunogenicity. The detection of antibody formation is highly dependent on the sensitivity and specificity of the assay. Additionally, the observed incidence of antibody (including neutralizing antibody) positivity in an assay may be influenced by several factors including assay methodology, sample handling, timing of sample collection, concomitant medications, and underlying disease. For these reasons, comparison of the incidence of antibodies to INCRELEX® with the incidence of antibodies to other products may be misleading.

Anti-IGF-1 antibodies were present at one or more of the periodic assessments in 14 of 23 children with Primary IGFD treated for 2 years. However, no clinical consequences of these antibodies were observed (e.g., attenuation of growth).

6.3 Post-Marketing Experience

The following adverse reactions have been identified during post approval use of INCRELEX®. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.

Systemic hypersensitivity: anaphylaxis, generalized urticaria, angioedema, dyspnea

In the post-marketing setting, the frequency of cases indicative of anaphylaxis was estimated to be 0.3%. Symptoms included hives, angioedema, and dyspnea, and some patients required hospitalization. Upon re-administration, symptoms did not re-occur in all patients.

Local allergic reactions at the injection site: pruritus, urticaria

Skin and Subcutaneous Tissue Disorders: alopecia, hair texture abnormal

General Disorders and Administrative Site Conditions: injection site reactions (e.g. erythema, pain, haematoma, haemorrhage, induration, rash, swelling)

Musculoskeletal and Connective Tissue Disorders: osteonecrosis/avascular necrosis (occasionally associated with slipped capital femoral epiphysis)

8.1 Pregnancy

8.3 Nursing Mothers

Excretion of INCRELEX® in human milk has not been studied. Caution should be exercised when INCRELEX® is administered to a nursing woman.

8.4 Pediatric Use

Safety and effectiveness in pediatric patients below the age of 2 years of age have not been established.

8.5 Geriatric Use

The safety and effectiveness of INCRELEX® in patients aged 65 and over has not been established.

8.6 Renal Impairment

No Studies have been conducted in Primary IGFD children or adult subjects with renal impairment [see Clinical Pharmacology (12.3)].

8.7 Hepatic Impairment

No studies have been conducted in Primary IGFD children or adult subjects with hepatic impairment [see Clinical Pharmacology (12.3)].