Investigational and experimental GnRH analogs and associated neurotransmitters.

The GnRH agonistic analogs enable for desensitizing the hypothalamo-pituitary-gonadal axis in malignant and benign conditions where minimizing the production of sex hormones, or blocking ovulation is necessary. The possible indications are prostate cancer, benign prostate hyperplasia, breast cancer, endometriosis, precocious puberty, uterine leiomyomata, assisted reproduction (ART)/in vitro fertilization (IVF), PCOS, minimizing the gonadotoxic effect of chemotherapy in young women, and possibly ovarian cancer. Areas covered: The aim of the current review is to summarize, giving a critical overview, of the investigational GnRH agonists, and shortly discuss the difference between the GnRH agonists, antagonists, Kisspeptin, and Neurokinin B analogs. Expert opinion: The broad armamentarium of agonists may make it possible, in the future, to expand the indications and uses of these analogs, choosing and specifically tailoring the analog to the required effect, while minimizing side effects.