• Triptorelin, leuprorelin and goserelin are gonadotrophin releasing hormone (GnRH) analogues that are licensed for monthly or 3-monthly treatment of a number of indications including prostate cancer, endometriosis and uterine fibroids.

• Triptorelin is available as 2 branded products – Decapeptyl SR and Gonapeptyl Depot whereas there is only one goserelin brand (Zoladex) and one leuprorelin brand (Prostap).

• The major use of GnRH analogues is for treatment of prostate cancer. The 2 triptorelin products have different indications. Decapeptyl is licensed for the treatment of patients with locally advanced, non-metastatic prostate cancer as an alternative to surgical castration, and for the treatment of metastatic prostate cancer. Gonapeptyl is licensed for the treatment of advanced, hormone-dependent prostate carcinoma. Leuprorelin is licensed for the treatment of advanced prostate cancer, while goserelin is licensed for prostate cancer suitable for hormonal manipulation.

• The vast majority of data for treatment of prostate cancer is for goserelin. One study has compared triptorelin and goserelin. There is a small amount of comparative information for triptorelin and leuprorelin.

• Triptorelin has demonstrated efficacy for treatment of endometriosis and as a class, GnRH analogues are considered to have comparable efficacy.

• For treatment of uterine fibroids the GnRH analogues are presumed to have comparable effects. The vast majority of information is on use of leuprorelin and goserelin.

• Both the monthly and 3-monthly goserelin products are administered by subcutaneous (SC) injection, both leuprorelin products are also administered by SC injection although the monthly product may be given by IM injection. In comparison both Decapeptyl products are given by IM injection. Gonapeptyl Depot is only available as a monthly preparation and can be given by IM or SC injection.

• The Decapeptyl preparations are cheaper than goserelin, leuprorelin and Gonapeptyl Depot. The development of a generic goserelin 3 month injection for treatment of hormone sensitive prostate cancer may change the market over the coming months and this should be monitored.

• The majority of the prescribing of GnRH analogues occurs in primary care. In terms of evidence for use and taking into account the combined costs of both primary and secondary care, goserelin and Decapeptyl (triptorelin) preparations appear to be the preferred GnRH analogues.

• The ultimate place in therapy of triptorelin will be determined by further comparative trials with leuprorelin and goserelin. The selection of one GnRH analogue over another should be driven by the licensed indications and the evidence for use, the side effect profile, the type of administration schedule desired and economic considerations.