Sotatercept

Source: UK SPC (eMC) §4.2 for Winrevair 45 mg powder and solvent for solution for injection (https://www.medicines.org.uk/emc/product/100843/smpc). Verbatim: 'Winrevair is administered once every 3 weeks as a single subcutaneous injection according to patient weight… Treatment is initiated with a single dose of 0.3 mg/kg… the dose should be escalated to the recommended target dose of 0.7 mg/kg… Treatment should be continued at 0.7 mg/kg every 3 weeks unless dose adjustments are required.' No separate maximum dose is stated in §4.2. INITIATION: treatment should only be initiated and monitored by a physician experienced in the diagnosis and treatment of PAH; haemoglobin (Hgb) and platelet count must be obtained prior to the first dose; initiation is contraindicated if platelet count is consistently < 50 x 10^9/L. MONITORING: Hgb and platelet count before each dose for the first 5 doses (or longer if values are unstable), then every 3 to 6 months. DOSE DELAY — delay treatment for 3 weeks (one dose delay) if: Hgb increases > 1.24 mmol/L (2 g/dL) from the previous dose and is above the upper limit of normal (ULN); Hgb increases > 2.48 mmol/L (4 g/dL) from baseline; Hgb increases > 1.24 mmol/L (2 g/dL) above ULN; or platelet count decreases < 50 x 10^9/L. Re-check Hgb and platelets before reinitiating. For delays lasting > 9 weeks, restart at 0.3 mg/kg and escalate to 0.7 mg/kg after verifying acceptable Hgb and platelet count; for delays > 9 weeks due to platelets consistently < 50 x 10^9/L, carry out a benefit/risk re-evaluation before reinitiating. MISSED DOSE: administer as soon as possible; if not taken within 3 days of the scheduled date, adjust the schedule to maintain 3-week dosing intervals. The SPC gives weight-band injection-volume tables for both 0.3 mg/kg and 0.7 mg/kg (30.0 kg up to 180.0 kg; 45 mg and 60 mg vial kits) — consult the SPC tables for the volume and kit type. ELDERLY: no dose adjustment required in patients ≥ 65 years. HEPATIC: no dose adjustment based on hepatic impairment (Child-Pugh A to C); not studied in hepatic impairment. PAEDIATRIC: safety and efficacy in children and adolescents below 18 years have not yet been established, no data available — verify any under-18 use against a children's formulary. Single use only; must be reconstituted before use; intended for use under the guidance of a healthcare professional, with patient/caregiver administration only after training.