2 The technology
2.1 Abiraterone acetate (Zytiga, Janssen) is a selective androgen synthesis inhibitor that works by blocking cytochrome P450 17 alpha‑hydroxylase. It blocks androgen production in the testes and adrenal glands, and in prostatic tumour tissue. Abiraterone is administered orally in combination with prednisolone or prednisone. It is indicated for treating 'metastatic castration resistant [hormone-relapsed] prostate cancer in adult men who are asymptomatic or mildly symptomatic after failure of androgen deprivation therapy in whom chemotherapy is not yet clinically indicated'. It is also indicated for treating 'metastatic castration resistant prostate cancer in adult men whose disease has progressed on or after a docetaxel-based chemotherapy regimen'.
2.2 The summary of product characteristics lists the following adverse reactions for abiraterone as being very common (that is, occurring in 1 in 10 or more people): diarrhoea, urinary tract infection, hypokalaemia (low blood potassium concentrations), hypertension (high blood pressure) and peripheral oedema (swelling of the limbs). The summary of product characteristics states that 'other important adverse reactions' are cardiac disorders, hepatotoxicity and fractures. For full details of adverse reactions and contraindications, see the summary of product characteristics.
2.3 The current list price of abiraterone is £2,930 for 120 tablets (excluding VAT; British national formulary [BNF], accessed online November 2015). The company has agreed a commercial access arrangement with NHS England, the details of which are confidential. This commercial access arrangement was agreed in July 2016, after guidance publication. It presents a change to the pricing arrangement that was considered during development of this guidance. The pricing arrangement considered during guidance development was that the company would reduce the list price to £2,300 for 120 tablets at the time of publication of NICE guidance. The company had also agreed a complex patient access scheme (PAS) with the Department of Health. This would have involved the NHS paying the new list price for abiraterone for the first 10 months of treatment. After 10 months, the company would have rebated the cost of any subsequent tablets prescribed. The commercial access arrangement agreed in July 2016 replaces the PAS and therefore the list price has not been changed and the PAS no longer applies.