The effectiveness of a modified Gui Zhi Fu Ling Wan formulation (Gynoclear™) for the treatment of endometriosis: a study protocol for a placebo-controlled, double-blind, randomised controlled trial

Background: Endometriosis is the presence of tissue similar to that of the endometrium outside the uterine cavity and is the most common cause of chronic pelvic pain. Current non-surgical treatments such as non-steroidal anti-inflammatories, oral contraceptive pills and hormonal treatments have limited effectiveness, and the side effect profile is bothersome. This study will evaluate the efficacy of Gynoclear (TM) by change in endometriosis-related pain based on the Endometriosis Pain Daily Diary (EPPD) scores. Methods: This randomised, double-blind, placebo-controlled trial will recruit a minimum of 90 adult participants across Australia who have a laparoscopic visualisation/confirmation of endometriosis in the last 5 years and have current moderate or greater pelvic pain. Participants will be randomly allocated in a 1:1 ratio to receive either Gynoclear (TM) (active) or placebo. Gyncolear's active ingredients are Carthamus tinctorius (Safflower), Cinnamomum cassia (Chinese cinnamon), Poria cocos (Hoelen), Paeonia suffriticosa (Tree peony), Paeonia lactiflora (Peony) and Salvia miltiorrhiza (Red sage). Participants are asked to complete a total of 5 months' worth of pain diary entries via the EPDD v3, including 1-month screening, 2-month treatment period and 1-month post-treatment follow-up. The primary outcome variable is change in endometriosis-related pain based on the EPDD v3 scores. Secondary outcomes include change in health-related quality of life via the Endometriosis Health Profile (EHP-30), SF-12 and EQ-5D scores as well as changes in rescue analgesic usage, dyspareunia and fatigue via the EPDD. Discussion: This study will determine the safety and efficacy of Gynoclear (TM) to reduce the severity and duration of non-cyclical pelvic pain, dysmenorrhoea, dyspareunia and other symptoms of endometriosis. Study outcomes will be of interest to health professionals and members of the public who suffer from endometriosis.