2 The technology
2.1 Tolvaptan (Jinarc, Otsuka Pharmaceuticals) is a selective vasopressin antagonist. By inhibiting the binding of vasopressin to the V2 receptors, tolvaptan reduces cell proliferation, cyst formation and fluid excretion. This reduces kidney growth and protects kidney function. Tolvaptan has a marketing authorisation in the UK 'to slow the progression of cyst development and renal insufficiency of autosomal dominant polycystic kidney disease (ADPKD) in adults with CKD stage 1 to 3 at initiation of treatment with evidence of rapidly progressing disease'.
2.2 The summary of product characteristics lists the following adverse reactions for tolvaptan: thirst, polyuria, nocturia, pollakiuria (frequent urination), serum alanine aminotransferase or aspartate aminotransferase elevation. Hepatotoxicity has been observed in some people having tolvaptan for autosomal dominant polycystic kidney disease. For full details of adverse reactions and contraindications, see the summary of product characteristics.
2.3 Tolvaptan is taken orally, twice daily as a split dose. Doses can be titrated according to tolerability up to a maximum total daily dose of 120 mg. It is available as 15 mg, 30 mg, 60 mg and 90 mg tablets, in 28‑day packs of split‑dose tablets, at a flat net price of £1208.20, equating to £43.15 per day, regardless of dose. The company provided these costs to NICE because the British National Formulary (BNF) had not listed the price at the time of producing this guidance. The annual cost of tolvaptan is estimated by the company to be £15,750 per person. The company has agreed a patient access scheme with the Department of Health. This scheme provides a simple discount to the list price of tolvaptan, with the discount applied at the point of purchase or invoice. The level of the discount is commercial in confidence. The Department of Health considered that this patient access scheme does not constitute an excessive administrative burden on the NHS.