3 The technology

3.1 Elosulfase alfa (Vimizim, BioMarin) is a recombinant form of the human N‑acetylgalactosamine‑6‑sulfatase enzyme. It is intended to replace the enzyme lacking in people with mucopolysaccharidosis type IVa (MPS IVa). Elosulfase alfa has a marketing authorisation in the UK for treating MPS IVa in people of all ages. It is given by intravenous infusion, over 4 hours, once a week. The recommended dosage is 2 mg/kg body weight each week, and treatment is anticipated to continue for life.

3.2 The summary of product characteristics lists the following adverse reactions for elosulfase alfa: anaphylaxis, hypersensitivity, headache, dizziness, shortness of breath, diarrhoea, vomiting, nausea, sore throat, abdominal pain, muscle pain, chills and fever. For full details of adverse reactions and contraindications, see the summary of product characteristics.

3.3 Elosulfase alfa is available in 5 ml vials containing 5 mg of elosulfase alfa, at a net price of £750 per vial (excluding VAT). NICE estimates that the average cost per year for elosulfase alfa is £394,680 per patient (based on the recommended dosage of 2 mg/kg/week and an average body weight of 25.3 kg). The company has proposed a patient access scheme, in which elosulfase alfa would be provided at a discounted cost; the discount is commercial in confidence and so cannot be reported here. The managed access agreement includes further commercial arrangements between the company and NHS England for the duration of the agreement.