Nusinersen

UK SPC (Spinraza 12 mg solution for injection, eMC product 2715), spinal muscular atrophy. Treatment should only be initiated by a physician with experience in the management of SMA, and the decision to treat should be based on an individualised expert evaluation of expected benefit against risk; patients with profound hypotonia and respiratory failure at birth, where Spinraza has not been studied, may not experience clinically meaningful benefit. Treatment should be initiated as early as possible after diagnosis. It is recommended that a volume of cerebrospinal fluid equivalent to the volume of Spinraza to be injected is removed prior to administration. Sedation may be required as indicated by the clinical condition of the patient, and ultrasound or other imaging techniques may be considered to guide administration, particularly in younger patients and those with scoliosis. The injection must not be given into areas of skin showing signs of infection or inflammation. Duration: long-term efficacy data are not available; the need for continuation should be reviewed regularly on an individual basis. DELAYED OR MISSED DOSES (SPC Table 1): a delayed or missed LOADING dose should be given as soon as possible with at least 14 days between doses, with subsequent doses continuing at the prescribed intervals from the last dose. For a missed MAINTENANCE dose: more than 4 to less than 8 months from the last dose — give as soon as possible, then the next dose per the original schedule provided the two are at least 14 days apart; 8 to less than 16 months — give as soon as possible then the next dose 14 days later; 16 to less than 40 months — give as soon as possible then two further doses 14 days apart; 40 months or more — administer the entire loading regimen on the prescribed intervals (Days 0, 14, 28 and 63). In each case a maintenance dose follows 4 months after the last dose and is then repeated every 4 months. Platelet count, coagulation laboratory testing and urine protein testing (preferably a first morning specimen) are recommended prior to administration if clinically indicated. Hepatic impairment: not studied; dose adjustment is unlikely to be required as nusinersen is not metabolised via the cytochrome P450 system. PAEDIATRIC USE: the dose is a FLAT 12 mg per administration with no per-kg component, and the same dose and schedule apply irrespective of age (the US label states safety and effectiveness have been established in paediatric patients from newborn to 17 years). paedDose is therefore null — there is no per-kg paediatric dose to record. Verify against a children's formulary. IMPORTANT DIVERGENCE TO RESOLVE — the US label in the same bundle (SPINRAZA, Biogen, label date 2026-03-31) now describes TWO regimen options: a Low Dose Regimen (12 mg loading doses and 12 mg maintenance every 4 months, with the fourth loading dose 30 days after the third rather than the UK's Day 63) and a High Dose Regimen (one 50 mg loading dose, a second 50 mg loading dose 14 days later, then 28 mg once every 4 months). The high-dose regimen and the 28 mg and 50 mg vial strengths are NOT in the retrieved UK SPC. A clinician must confirm current UK licensing before publication.