The 23rd annual conference of the European Society of Human Reproduction and Embryology today revealed a promising new therapy for protecting the fertility of women with cancer and auto-immune diseases such as lupus.
Dr. Kate Stern, Research Director of the Royal Women's Hospital, Melbourne, Australia, told the conference that her pilot study had shown gonadotropin-releasing hormone (GnRH) antagonists were likely to be able to protect the ovary in women receiving potentially toxic doses of chemotherapy. "We are now hoping to carry out a randomised controlled trial to assess the long term protective effect of this treatment", she said.
GnRH analogues are commonly used in the management of women's disorders that are dependent on oestrogen production, and in IVF therapies. Dr. Stern and her team studied women between the ages of 18 and 35 years who were due to receive high doses of cyclophosphamide, a chemotherapy drug.
They knew that GnHR analogues were already used for the temporary suppression of ovulation in infertility treatment, so reasoned that it would be possible to use it to shut down the ovaries temporarily during the time that chemotherapy was administered, and hence protect them from the effect of the drugs.
The women were given the GnRH antagonist cetrorelix by 3 subcutaneous injections, each of them four days apart, concurrently with their chemotherapy.
The scientists observed that there was evidence that ovarian function was suppressed, but that this returned to normal after chemotherapy stopped. Follicle stimulating hormone levels were up in 73% of the patients, but these also subsequently returned to normal. 94% of the patients resumed spontaneous ovulation and menses within 12 months.
"We believe that using GnRH antagonists in this way could reduce the side effects of chemotherapy over a long period", said Dr. Stern. "Other studies have tried to analyse whether similar treatments work, but the medications used have been long-acting and therefore cause shutdown for the whole time the patient is in chemo.
This means that patients get unpleasant side effects related to having low oestrogen levels, such as hot flushes, and can also lead to loss of bone mass."
The side effects associated with the cyclical use of GnRH antagonists were minimal, she said. "19% of patients did not experience any at all, and only 6% reported persistent side effects, none of which were dangerous or serious."
Dr. Stern and her team are currently completing a five year follow up of the pilot study. "We are optimistic that this will prove to be an effective way of protecting fertility for women without the problems that have been associated with GnRH agonists in the past", she said.
"The medical community needs to acknowledge the importance of future fertility for young people having cancer treatment. Not all patients who are having cancer treatment have the opportunity to talk with a fertility specialist before beginning treatment, and yet there are already several options for protecting the ovaries and even preserving eggs, embryos, or ovarian tissue.
In addition to raising awareness among the medical profession, more support is needed for research in this important area."