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Expert opinion: Another arbitrary decision on Abiraterone?

Published: Mon 21 Mar 2016
Expert opinion: Another arbitrary decision on Abiraterone?

Prostate cancer is the most common male-specific cancer with around 35,000 new cases each year in the UK, resulting in about 10,000 deaths. Fortunately, there are a wide and generally effective range of treatment options available, chief amongst which is hormone therapy, aimed at blocking androgen (testosterone) production.

The rationale for this treatment is that most prostate tumors, especially in the earlier stages of the disease, require androgens for their continued growth and survival, in much the same way that some breast cancers are dependent on estrogen. The original treatment for depriving prostate tumors of androgen was the removal of the testicles, giving rise to the delightful term “castration resistant prostate cancer”. Castration was subsequently replaced with drug-based therapy, of which abiraterone, developed in the early 1990s by Mike Jarman, Elaine Barrie, and Gerry Potter of the Cancer Research UK (CRUK) Centre for Cancer Therapeutics in the Institute of Cancer Research, London, is considered to be one of the most effective as it almost completely blocks testosterone production.

Hormone therapy is not without side effects, as it can (and usually does) lead to varying degrees of feminization. However, these effects are generally far less severe than those associated with therapies used when tumors fail to respond to hormone treatment, which include conventional chemotherapy with cytotoxic drugs that are generally designed to selectively kill rapidly dividing cells. Many normal adult cells also need to divide quickly though, for example those involved in replacing the lining of the gut or in generating new blood cells, and consequently this type of chemotherapy can have a broad and significant range of side effects. Abiraterone delays the need for chemotherapy by helping to overcome the problem of castration resistant tumors – in which the cancer cells become more and more sensitive to androgen in response to its reduced levels after hormone therapy. This has been supported by a number of large clinical trials, including one that recruited 1,088 men and revealed that abiraterone increased the average time taken for prostate cancer to spread from 8.3 months to 16.5 months.

Despite this, the National Institute for Health and Care Excellence (NICE) refused to approve the use of abiraterone for prostate cancer on the grounds that its cost (originally £3,000 per month) was not justified by its proven clinical benefits. NICE have now reversed this decision based on additional information supplied by its manufacturer, Janssen, and abiraterone can be given to prostate cancer patients who currently have mild symptoms but some evidence of the disease spreading, and who have not previously responded to hormone therapy and have not undergone radiotherapy. However, it does not seem entirely clear what this new data is, or why the current, published data was considered to be insufficient, and therefore there is a risk that these decisions could appear to be arbitrary.

A more fundamental point though would seem to be this: the drug was initially developed by CRUK using money donated by cancer survivors, the families of cancer patients, and numerous other individuals and organizations. And yet the final product has until recently been prohibitively expensive, to the point where thousands of men may have missed out on its potential benefits, and it has severely strained NHS budgets.

Prof Richard Morgan, Director, Institute of Cancer Therapeutics reacting to BBC News article on U-turn over prostate cancer drug after price change.

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