GENOTROPIN

What it is

GENOTROPIN is somatropin (rbe) powder for injection with diluent, available in multiple formulations including GENOTROPIN and GENOTROPIN GoQuick cartridges, and GENOTROPIN MiniQuick single dose syringes. GENOTROPIN and GENOTROPIN GoQuick are available in strengths of 5 mg/mL, 5.3 mg/mL, and 12 mg/mL after reconstitution. GENOTROPIN MiniQuick contains somatropin ranging from 0.2 mg to 2.0 mg in 0.25 mL. GENOTROPIN is administered by subcutaneous injection.

Approved indications

— Short stature due to decreased or failed secretion of pituitary growth hormone. — Severe growth hormone deficiency in adults 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. — Growth disturbances associated with gonadal dysgenesis (Turner syndrome). — Improvement of body composition and treatment of short stature associated with Prader-Willi syndrome in paediatric patients. — Growth disturbance in children with chronic renal insufficiency whose height is on or less than twenty-fifth percentile and whose growth velocity is on or less than twenty-fifth percentile for bone age.

Dosing overview

Dosing is individualised and varies by indication. The weekly dose is given in divided doses, 6 to 7 times per week.

Key safety warnings

Fatalities have been reported in paediatric patients with Prader-Willi syndrome who had one or more risk factors including severe obesity, history of respiratory impairment or sleep apnoea, or unidentified respiratory infection. Patients with Prader-Willi syndrome should be evaluated for upper airway obstruction before initiation of treatment, and treatment should be interrupted if signs of upper airway obstruction develop during therapy. Somatropin reduces insulin sensitivity and patients should be observed for evidence of glucose intolerance. In rare cases type 2 diabetes mellitus may be fulfilled as a result of growth hormone therapy, particularly in patients with risk factors such as obesity, family history, or steroid treatment. Growth hormone can be used in patients with already manifest diabetes mellitus, however it requires special care and adjustment of anti-diabetic therapy may be necessary. Introduction of somatropin treatment may inhibit 11β-hydroxysteroid dehydrogenase type 1 and result in reduced serum cortisol concentrations, potentially unmasking previously undiagnosed central hypoadrenalism. Patients on glucocorticoid replacement therapy may require increased maintenance or stress doses following initiation of somatropin treatment. In two placebo controlled trials involving 522 critically ill adult patients, mortality was higher in patients treated with 5.3 mg or 8 mg GENOTROPIN daily compared to placebo (41.9% versus 19.3%).

Contraindications

GENOTROPIN should not be used in patients with active tumours or evidence of tumour growth, and anti-tumour therapy must be completed prior to starting therapy. It should not be used for growth promotion in children with closed epiphyses. Known hypersensitivity to metacresol is a contraindication for GENOTROPIN formulations with preservative. Patients with acute critical illness suffering complications following open heart surgery, abdominal surgery, multiple accident trauma, extensive burns or acute respiratory failure should not be treated with GENOTROPIN. Somatropin is contraindicated in patients with Prader-Willi syndrome who are severely obese or have severe respiratory impairment.

PBS listing

GENOTROPIN is listed on the PBS in multiple strengths, ranging from 0.4 mg (1.2 i.u.) to 2.0 mg (6 i.u.) in single use syringes without preservative, and 5 mg (15 i.u.) and 12 mg (36 i.u.) in pre-filled pens with preservative. All PBS items require authority approval, with ex-manufacturer prices ranging from A$87.56 to A$437.81 depending on strength.

Regulatory history

GENOTROPIN 5.3 mg/mL was first registered on the ARTG on 2 December 1991. GENOTROPIN MINIQUICK single dose presentations ranging from 0.2 mg to 2.0 mg were first listed on 3 November 2000. GENOTROPIN 5.0 mg and 12 mg strengths were registered on 2 July 2001 and 20 August 2003 respectively. GENOTROPIN GoQuick pre-filled pens in 5 mg, 5.3 mg and 12 mg strengths were first listed on 5 March 2010. In March 2016, the PBAC recommended listing for growth hormone deficiency, Turner syndrome, Prader-Willi syndrome and chronic renal insufficiency. In July 2017, the PBAC recommended listing for adults with severe growth hormone deficiency under Section 100 special arrangements. In May 2024, the PBAC recommended amending Section 100 to enable adults with established hypothalamic-pituitary disease to access somatropin without dynamic testing.