Norditropin FlexPro

What it is

Norditropin FlexPro is a biosynthetic human growth hormone injection solution containing somatropin. Somatropin is a polypeptide hormone of recombinant DNA origin, synthesised by a modified strain of E coli bacteria, and contains the identical sequence of 191 amino acids constituting the naturally occurring pituitary human growth hormone. Norditropin FlexPro is available in strengths of 5 mg, 10 mg or 15 mg in 1.5 mL. It is supplied as a colourless solution for injection.

Approved indications

Children: — Treatment of growth failure in children due to pituitary growth hormone deficiency. — Treatment of growth failure in girls due to gonadal dysgenesis (Turner Syndrome). — Treatment of growth failure in children due to chronic renal insufficiency whose height is on or less than the twenty-fifth percentile and whose growth velocity is on or less than the twenty-fifth percentile for bone age, where chronic renal insufficiency is defined as a glomerular filtration rate of less than 30 mL/min/1.73 m². — Treatment of severe growth failure due to intrauterine growth retardation in children born small for gestational age without spontaneous catch-up growth by two years of age. Adults: — Treatment of adults with severe growth hormone deficiency as diagnosed in the insulin tolerance test for growth hormone deficiency and defined by peak growth hormone concentrations of less than 2.5 nanogram/mL.

Dosing overview

Treatment with Norditropin should be directed by specialists experienced in the diagnosis and management of growth hormone deficiency, Turner syndrome, chronic renal disease and small for gestational age conditions. The dosage must be individualised for each patient in accordance with the individual's response to therapy. Generally, daily subcutaneous administration in the evening, 6–7 days per week, is recommended.

Key safety warnings

Serum thyroxine levels may fall during treatment due to increased peripheral deiodination of T4 to T3, and hypothyroidism may develop in patients with pituitary disease. Patients should have periodic thyroid function tests and thyroid hormone should be substituted when indicated. Leukaemia has been reported in a small number of growth hormone deficient patients, some of whom have been treated with somatropin. Based on current evidence it is unlikely that somatropin is responsible for this. In patients in complete remission from tumours or malignant disease, growth hormone therapy has not been associated with an increased relapse rate, but patients should be followed closely for relapse after commencement of Norditropin therapy. Treatment with Norditropin may decrease insulin sensitivity and hyperglycaemia may occur, potentially unmasking previously undiagnosed impaired glucose tolerance and diabetes mellitus. Glucose levels should be monitored periodically in all patients, especially those with risk factors such as obesity, Turner syndrome, or a family history of diabetes mellitus. Although rare, pancreatitis should be considered in Norditropin-treated patients who develop abdominal pain, especially in children. Very rare cases of benign intracranial hypertension have been reported. In cases of severe or recurrent headache, visual symptoms, nausea and/or vomiting, fundoscopy for papilloedema is recommended, and if confirmed, growth hormone treatment should be discontinued.

Contraindications

Norditropin should not be used in children with closed epiphyses, in patients with retarded growth due to any other cause than pituitary growth hormone deficiency unless specifically indicated, or in patients with known hypersensitivity to any of the ingredients. Norditropin should not be used in patients with any evidence of active malignant tumours, and intracranial neoplasm must be inactive and anti-tumour therapy must be completed prior to instituting Norditropin therapy. Growth hormone is contraindicated in patients with proliferative or preproliferative diabetic retinopathy. Growth hormone is contraindicated in patients with Prader-Willi syndrome who are severely obese or have respiratory impairment. Norditropin should not be initiated to treat patients with acute critical illness due to complications following open heart surgery or abdominal surgery, multiple accident trauma or acute respiratory failure.

PBS listing

Norditropin FlexPro is listed on the PBS in three strengths: 5 mg (15 IU) in 1.5 mL pre-filled pen at A$151.51 ex-manufacturer price, 10 mg (30 IU) in 1.5 mL pre-filled pen at A$312.72 ex-manufacturer price, and 15 mg (45 IU) in 1.5 mL pre-filled pen at A$469.08 ex-manufacturer price. All strengths are restricted and require authority approval.

Regulatory history

Norditropin FlexPro somatropin (rbe) 5 mg, 10 mg and 15 mg injection-solution pre-filled cartridges were first listed on the ARTG on 9 May 2011.