Analogues of
luteinizing hormone-releasing hormone (
LH-RH) have made possible new approaches to the treatment of some
hormone-dependent
cancers and diseases and conditions which result from inappropriate
sex hormone levels. In the fields of both gynaecology and oncology, the development of sustained delivery depot systems has played a key role in the clinical use of
LH-RH agonists and will be also essential for the
LH-RH antagonists. Clinical results show that
therapy with agonists of
LH-RH is the preferred method of treatment for men with advanced
prostate cancer. For
prostate cancer and other indications, the new
LH-RH antagonists such as
Cetrorelix may offer an advantage based on the fact that they inhibit LH, FSH and sex-
steroid secretion from the start of the administration and thus reduce the time of the onset of
therapeutic effects. The use of antagonists would avoid the temporary clinical "flare-up" of the disease which can occur with the agonists in men with
prostate cancer. The rapid shrinkage of the prostate and improvement in urinary symptoms obtained with
Cetrorelix in men with
benign prostatic hyperplasia (BHP) suggests that
LH-RH antagonists offer a therapeutic alternative in patients who are considered poor surgical risks. Various experimental and clinical studies suggest that analogues of
LH-RH might be useful for treatment of premenopausal women with oestrogen-dependent
breast cancer.
LH-RH antagonists such as
Cetrorelix could be also considered for hormonal
therapy of
epithelial ovarian cancer which responds only marginally to the agonists, and for treatment of
endometrial cancer. Many investigators have reported beneficial effects of
LH-RH agonists in the treatment of patients with
leiomyomas.
LH-RH antagonists also appear to be promising for
therapy of uterine
leiomyomas, and in addition might be useful for treatment of
endometriosis and polycystic
ovarian disease (PCOD).
LH-RH agonists have been employed in in vitro fertilization and embryo transfer (IVF-ET) programs to prevent a premature rise in LH and various results suggest that the use of antagonist
Cetrorelix in assisted reproduction procedures, could be even more advantageous. For most of these indications, the use of sustained release
depot preparations will be required.