Givosiran (Givlaari, Alnylam) is a small-interfering ribonucleic acid that suppresses delta-aminolevulinic acid synthase 1 production by the liver. This reduces the level of toxic precursors of porphyrin. Givosiran has a marketing authorisation in the UK for 'treating acute hepatic porphyria in adults and adolescents aged 12 years or older'. It is administered by subcutaneous injection. The recommended dose is 2.5 mg per kg body weight once a month.
Very common adverse reactions (that is, occurring in 1 in 10 people or more) include injection site reactions, nausea and fatigue. Elevated transaminases and anaphylactic reactions have led to people stopping treatment. For full details of adverse reactions and contraindications, see the summary of product characteristics.
The price for givosiran is £41,884.43 per 189 mg vial (excluding VAT; company's evidence submission). The company has a commercial arrangement. This makes givosiran available to the NHS with a discount. The size of the discount is commercial in confidence. It is the company's responsibility to let relevant NHS organisations know details of the discount.