Steroidal 'add-back' therapy in patients treated with GnRH agonists

GnRH analogues (GnRH-a) are well established in the treatment of endometriosis. However, due to hypooestrogenic effects, treatment is limited to 6 months. The aim of this randomized, double-blind, comparative study was to evaluate whether symptoms and signs of hypooestrogenism, e.g. hot flushes, sweating and sleeplessness, could be avoided by a steroidal add-back regimen, while the beneficial effect of a GnRH-a on endometriosis could be maintained. In group A, 14 patients were treated with 3.75 mg leuprorelin acetate depot per month i.m. in combination with 20 mg ethinyloestradiol plus 0.15 mg desogestrel orally for 3 weeks. In group P, 13 patients received leuprorelin acetate, following the same schedule as in group A, and placebo. Treatment duration was 6 months. At first-look laparoscopy (postoperatively) group A had an r-AFS score of 23.57 and group P of 24.23. After 6 months of treatment with leuprorelin acetate depot r-AFS scores had dropped to 16.14 in group A and to 6.25 in group P at second-look laparoscopy, achieving statistical significance in both groups (p < 0.001). Hypooestrogenic adverse drug reactions (e.g. hot flushes, sweating and sleeplessness) were more frequently reported in group P, whereas the occurrence of headache was comparable in both groups. Dysmenorrhoea was significantly reduced in both groups, whereas dyspareunia was only decreased in group P. Variations in laboratory values were within normal ranges and did not give any concern about drug safety. Loss of bone mineral density caused by the GnRH-a was reduced by the combined oestrogen/progestin add-back therapy. In conclusion, this therapy can lead to a reduction in hypooestrogenic adverse drug reactions and mostly preserves agonist efficacy with the chance of treatment prolongation.