SAIZEN

What it is

SAIZEN is somatropin (rmc), recombinant human growth hormone . It is presented as a sterile liquid (opalescent white to off-white solution, practically free from visible particles) in glass cartridges for multidose use . Available strengths are 6 mg/1.03 mL (5.83 mg/mL), 12 mg/1.5 mL (8.00 mg/mL) or 20 mg/2.5 mL (8.00 mg/mL) .

Approved indications

— Growth failure in children due to human growth hormone deficiency . — Growth failure in girls with gonadal dysgenesis (Turner Syndrome), confirmed by chromosomal analysis . — Growth disturbance (growth retardation) in pre-pubertal children due to chronic renal insufficiency . — Growth disturbance (current height standard deviation score (H SDS) <-2.5 and parental adjusted H SDS <-1) in short children born small for gestational age (SGA) with a birth weight and/or length below -2 standard deviations (SD), who failed to show catch-up growth (height velocity standard deviation score (HV SDS) <0 during the last year) by four years of age or later . — Replacement therapy in adults with pronounced growth hormone deficiency as diagnosed in 2 different dynamic tests for growth hormone deficiency and defined by peak GH concentrations of less than 2.5 nanogram/mL .

Dosing overview

Dosing varies according to indication. For treatment of growth failure due to growth hormone deficiency in children, the recommended weekly dose is 0.2 mg/kg body weight or 4 mg/m² BSA, which may be divided into 3, 6, or 7 single doses per week . For treatment of growth failure in girls with Turner Syndrome, the recommended daily dose is 0.045–0.05 mg/kg body weight or 1.4 mg/m² BSA . For treatment of growth disturbance in children with chronic renal insufficiency, the recommended daily dose is 0.045–0.05 mg/kg body weight or 1.4 mg/m² BSA . For treatment of growth disturbance in short children born small for gestational age, the recommended starting daily dose is 0.035 mg/kg body weight or 1 mg/m² BSA, which may be increased to a maximum recommended dose of 0.067 mg/kg/day (2 mg/m²/day) based on clinical judgement . For treatment of growth hormone deficiency in adults, low doses of 0.15–0.3 mg are recommended as a daily subcutaneous injection, with the dose titrated carefully guided by IGF-1 age-adjusted normal values and clinical effect; the recommended final dose seldom exceeds 1.0 mg/day .

Key safety warnings

When somatropin is administered subcutaneously at the same site over a long period, localised lipoatrophy may result, but this can be avoided by frequent rotation of the injection site . Fluid retention is expected during growth hormone replacement therapy in adults; in case of persistent oedema or severe paraesthesia, the dosage should be decreased in order to avoid the development of carpal tunnel syndrome . In critically ill patients, the effects of E-coli-derived growth hormone were studied in two placebo-controlled clinical trials involving 522 adult patients who were critically ill due to complications following open heart or abdominal surgery, multiple accident trauma, or acute respiratory failure; mortality was higher (41.9% vs 19.3%) among growth hormone treated patients than among those receiving placebo, and these patients must not be treated with somatropin . Hypothyroidism may appear during therapy with SAIZEN and should be corrected with thyroid hormone; thyroid assessment should be undertaken before starting SAIZEN therapy and not less frequently than annually . Because somatropin can decrease insulin sensitivity, patients treated with growth hormone should be monitored for evidence of glucose intolerance; SAIZEN should be used with caution in patients with diabetes mellitus or with a family history of diabetes mellitus, and the insulin dose may require adjustment . Fundoscopic examination should be performed routinely before initiating treatment with SAIZEN to exclude pre-existent papilloedema; in case of severe or recurrent headache, visual problems, nausea and/or vomiting, fundoscopy is recommended, and if papilloedema is confirmed, a diagnosis of idiopathic intracranial hypertension should be considered and the growth hormone treatment should be discontinued .

Contraindications

SAIZEN should not be used for growth promotion in children/patients with closed epiphyses . SAIZEN should not be used in patients with hypersensitivity to any constituent of the product . SAIZEN is contraindicated where there is evidence of an active intracranial lesion; intracranial lesions must be inactive for 12 months prior to instituting therapy and SAIZEN should be discontinued if there is any evidence of recurrent activity . SAIZEN is contraindicated in patients with active neoplasia (either newly diagnosed or recurrent); any pre-existing neoplasia should be inactive and any anti-tumour treatment must be completed prior to starting treatment . SAIZEN is contraindicated in patients with proliferative or preproliferative diabetic retinopathy . SAIZEN should not be initiated to treat patients with acute critical illness due to complications following open heart or abdominal surgery, multiple accident trauma, patients having acute respiratory failure or patients with similar conditions .

PBS listing

SAIZEN solution for injection is listed on the PBS in three strengths: 6 mg in 1.03 mL cartridge (ex-manufacturer price A$181.81), 12 mg in 1.5 mL cartridge (ex-manufacturer price A$363.62), and 20 mg in 2.5 mL cartridge (ex-manufacturer price A$625.45) . All strengths are subject to authority required restriction .

Regulatory history

SAIZEN somatropin (rmc) was first listed on the ARTG on 22 August 2011 in three strengths: 6 mg/1.03 mL, 12 mg/1.5 mL, and 20 mg/2.5 mL solution for injection multidose cartridges . In September 2023, PBAC recommended SAIZEN for severe late onset growth hormone deficiency .