Wednesday, December 03, 2014

Off label promotion of cabergoline for treating endometriosis

Endometriosis is a distressing disease , and difficult to treat . Even though it’s so common, we still don't know what causes it , and most medications just provide temporary suppression . We can’t cure it, which is why doctors are looking for new ways of tackling this disease . Pharmaceutical companies spend a lot of money in doing research in order to find new treatments, and everyone would be very happy when we can find something which works . However, developing a new drug is very expensive, and takes a lot of time and money.

Doctors are also happy to try new approaches, and a medical journal paper described a new way of treating endometriosis , using an old drug called cabergoline. The hypothesis was that some patients with endometriosis have high prolactin levels , and since cabergoline reduces high prolactin levels , it may help in treating endometriosis . Also, in vitro studies have shown that cabergoline reduces angiogenesis ( new blood vessel formation) by reducing levels of VEGF ( vascular endothelial growth factor).  The study was a small one, and showed that cabergoline was slightly more effective in reducing the size of a chocolate cyst ( endometrioma) as compared to the standard treatment which uses GnRH agonist injections.

While it’s promising that doctors are trying out new approaches to treating endometriosis, the problem is that this is only a small single study , which measures only a reduction in the size of endometriomas, which is quite a pointless result from the patient’s perspective. These studies need to be repeated by other doctors, to see if the drug helps in relieving the pelvic pain of endometriosis; or in improving their fertility before we can start recommending it in clinical practise. This can take time, and needs patience.

However, the tragedy is that when pharmaceutical companies come across a drug which is already being used for treating other diseases , and they find a paper which shows that it can also be used for treating endometriosis , they are very happy to promote this drug for that disease. This called an off-label use of the medicine, and while it’s quite ethical for doctors to prescribe this for their patients, it’s not ethical ( or legal) for companies to do so.

The problem is that when this drug is being actively promoted by MRs, gynecologists often don’t bother to read the fine print, or take the trouble to understand the limitations of the research. They fail to factor in the fact that a 25% reduction in the size of an endometrioma is of  very limited clinical importance – and that GnRH agonists have been shown to be quite ineffective in “treating” chocolate cysts, so there’s little point in comparing cabergoline with the GnRH agonists for this indication ! However, they are quite happy to do whatever the MR suggests. Doctors are always happy to prescribe medicines, because it gives them ( and their patients) the satisfaction that they are doing something ( even if it maybe ineffective). They get carried away by the “research” published in a foreign medical journal”, and are very pleased that they are doing something “new and different” for their patients.  Because the drug can be taken orally, doctors will tend to overprescribe it, because of the active promotional campaign being carried out by the pharma company. While this is good for the company  ( because it’s an expensive drug), it’s very unlikely that the poor endometriosis patient will benefit.

I'm not saying that cabergoline may not help patients with endometriosis. My point is that it has not been adequately documented to be proven to be an effective treatment for endometriosis , and until this is done, it should not be promoted to unsuspecting doctors and hoisted on clueless patients.

It seems that the pharma company is misusing one single article published in a medical journal in order to increase its drug sales. Rather than do this, they should promote clinical trials, to assess the efficacy
( or the lack of efficacy) of cabergoline in reducing the pelvic pain in patients with endometriosis, so that doctors learn when the drug is useful, and when it is not, so that they can prescribe it intelligently/

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