EnCyzix

EnCyzix is a medicine that contains the active substance enclomifene. It was to be available as capsules to be taken by mouth.

EnCyzix was expected to be used to treat hypogonadotropic hypogonadism in men. In this condition, the sex organs (the testes in men) do not work properly resulting in symptoms such as infertility, low libido, impotence, weakened bones and weight gain. EnCyzix was to be used in overweight men with a body mass index (BMI) of at least 25 kg/m².

Overweight men with hypogonadotropic hypogonadism produce too much of the hormone oestrogen. This stops the release of other hormones called gonadotrophins, which are needed for the testes to produce testosterone and to work normally. EnCyzix blocks the excess oestrogen enabling release of gonadotrophins and normal testicular function.

The company presented the results of 4 main studies involving a total of 588 patients. Patients were given either EnCyzix, or placebo (a dummy treatment) with and without application of a testosterone gel. The main measures of effectiveness were the amount of sperm produced and testosterone levels.

The CHMP noted that although the studies showed an increase in testosterone levels with EnCyzix, they did not look at whether EnCyzix would improve symptoms such as bone strength, weight gain, impotence and libido. In addition, there is a risk of venous thromboembolism (problems due to the formation of blood clots in the veins) with the medicine. Therefore, the CHMP was of the opinion that the benefits of EnCyzix did not outweigh its risks and recommended that it be refused marketing authorisation.

The company informed the CHMP that there are no ongoing clinical trials or compassionate use programmes with EnCyzix.