Cost regulators for NHS treatments in England and Wales have opened a second consultation on the use of Astellas' Xtandi (enzalutamide) in patients with prostate cancer, after widening the drug's target population.

The National Institute for Health and Care Excellence (NICE) has this morning (Tuesday) issued new draft guidance endorsing the use of Xtandi in adult patients with hormone relapsed metastatic prostate cancer.

The has a different mechanism of action from other anti androgens on the market; it works by blocking the binding of androgens to androgen receptors, prevents activated androgen receptors from migrating to the nucleus, and blocks the interaction of the activated androgen receptor with DNA in the nucleus to help prevent the spread of the disease.

As it stands, NICE is advising that the drug is used in patients only when their disease has progressed during or after a docetaxel-containing chemotherapy regimen and they have not been treated with Johnson's & Johnson's prostate cancer drug Zytiga (abiraterone).

This marks a change from first draft guidance published last October, which specified that Xtandi should only be used for people whose disease has progressed during or after one docetaxel-containing chemotherapy, and not any number of such regimens, a limitation which has now been removed thus widening the drug's potential scope. 

NICE says its independent appraisal committee heard that while both Xtandi and Zytiga are oral treatments, only Xtandi can be taken on a full stomach, making it more convenient to take. In addition, panel was also told that Xtandi can help control the cancer longer because there is no need to reduce the dose to prevent liver toxicity, as with Zytiga.

The cost regulator also stipulated that its endorsement is dependent on the continued provision of Xtandi at a confidential discount under a patient access scheme, bringing its average cost down from the £25,269 (as based on the list price).

Patients who were on Zytiga denied access to Xtandi

The guidance has not gone down well with Astellas however, given that NICE added a new limitation that patients who have previously received Zytiga no longer have access to Xtandi. The firm is especially disappointed given that this was not included in the original NICE guidance.

Alan McDougall, medical director at Astellas UK, said the announcement "represents a major setback for many prostate cancer patients who would otherwise be eligible for treatment with enzalutamide according to the original draft guidance and licensed indication". He added that the company "is concerned that such an approach has not been taken with similar appraisals for other cancer agents and leaves prostate cancer patients disadvantaged".

The Scottish Medicines Consortium recommended the use of Xtandi on NHS Scotland last November, with no additional restrictions.