Mirena is an intrauterine device (IUD) that releases a medicine, levonorgestrel, directly into the uterus. It is authorised for contraception, reduction of heavy menstrual bleeding (menorrhagia) and protection from endometrial hyperplasia during oestrogen replacement therapy. Since Mirena first became available in the United Kingdom women have been able to obtain it through the national health service.
The Medicines and Healthcare product Regulatory Agency (MHRA), together with independent expert advice for the Commission on Human Medicines is responsible for ensuring that medicines, including Mirena, have met appropriate standards of efficacy, safety and quality before they are granted a marketing authorisation and for ensuring that the benefits of treatment continue to outweigh the risks post authorisation, as further evidence emerges.
In addition to efficacy studies conducted by the marketing authorisation holder, Schering Health, prior to grant of a marketing authorisation, the Department has funded a number of studies to evaluate the effectiveness of Mirena (mainly in the indication of menstrual bleeding). These include the ongoing ECLIPSE randomised controlled trial in 1,200 women with menorrhagia.
The MHRA monitors the safety of all medicines, including Mirena, by evaluating data including adverse reaction reports received through the Yellow Card Scheme, published data, company studies and safety reviews, and information from other regulatory authorities. The benefits associated with Mirena are currently considered to outweigh the risks in its licensed indications.
The safety of Mirena was recently subject to European review and this has lead to a recommendation to clarify advice about the recognised risks of ectopic pregnancy and uterine perforation. As a precautionary measure, Mirena will be contraindicated in women with progesterone-dependent cancers. The product information for health professionals is being updated to reflect this advice.
The marketing authorisation holder is planning two studies: one to compare the risk of breast cancer in Mirena users with the risk in copper IUD users and users of other hormonal contraceptives and the other to compare the risk of uterine perforation in Mirena users with that in copper IUD users.