A prospective, single-centre, single-arm, open label study of the long term use of a gonadotropin releasing hormone agonist (Triptorelin SR, 11.25 mg) in combination with Tibolone add-back therapy in the management of chronic cyclical pelvic pain

Background: Chronic cyclic pelvic pain (CCPP) affects women's quality of life and pituitary downregulation is often used for symptomatic relief. However, prolonged suppression of ovarian function is associated with menopausal side effects and can lead to osteoporosis. Currently, the use of gonadotropin releasing hormone agonists (GnRHa) for treatment of CCPP is usually restricted to 6-9 months, limiting their efficacy. There is limited information regarding safety and efficacy with longer-term use. The aim of this study is to examine the safety and efficacy of long-term (24 months) pituitary down-regulation with the GnRHa (Triptorelin SR) with add-back therapy (ABT) using Tibolone for symptom relief in women with CCPP. Methods: A single-arm, prospective clinical trial at a Tertiary University Teaching Hospital of 27 patients receiving Triptorelin SR (11.25 mg) and Tibolone (2.5 mg). Outcomes measures were the safety of treatment assessed by clinical examination, haematological markers, liver and renal function tests and bone mineral density (BMD) at 12, 18 and 24 months as well as at 6 months post-treatment. Pain and health-related quality of life (HR-QoL) assessed using the endometriosis health profile (EHP-30) and chronic pain grade (CPG) questionnaires. Results: There was no evidence for any significant harmful effects on any of the measured haematological, renal or liver function tests. Although results regarding the effect on BMD are not conclusive there is an increased risk of development of osteopaenia after 12 months of treatment. Pain and HRQoL assessments showed significant improvement during medication, but with deterioration after treatment cessation. Conclusion: Long- term Triptorelin plus Tibolone add-back therapy in women suffering from CCPP does not appear to be associated with significant serious adverse events apart from the possibility of deterioration in the BMD that needs to be monitored. This mode of therapy appears to be effective in pain relief and in improving quality of life over a 24-month period.