Hope Medicine has announced positive interim results from a global phase II clinical trial evaluating HMI-115, a novel monoclonal antibody therapy for Endometriosis. The investigational drug, which targets the prolactin receptor, represents a first-in-class approach for managing endometriosis-associated pain.

The randomised, double-blind, placebo-controlled study enrolled 142 women across the United States, Poland and China. Interim analysis of the first 102 patients demonstrated statistically significant reductions in both menstrual (dysmenorrhea) and non-menstrual pelvic pain. Patients receiving HMI-115 (240 mg every two weeks) experienced a 42 percent reduction in dysmenorrhea pain and a 50 percent reduction in non-menstrual pelvic pain compared to baseline, outperforming placebo.

Importantly, the treatment was well tolerated, with no treatment-related serious adverse events reported. Unlike existing hormonal therapies, HMI-115 did not disrupt normal menstrual cycles or alter key sex hormone levels such as estradiol, luteinising hormone (LH), Follicle-Stimulating Hormone (FSH), or progesterone. No significant changes in bone mineral density were observed and patients did not report typical menopausal symptoms.

Experts highlighted the significance of the findings, noting the long-standing need for treatments that provide pain relief without impacting hormonal balance. Current therapies, including GnRH blockers, often come with side effects such as bone loss and menopausal symptoms, limiting their long-term use.

HMI-115 has already received Breakthrough Therapy Designation from the National Medical Products Administration, underscoring its potential to address a critical unmet need. The company plans to initiate discussions with global regulators, including the US Food and Drug Administration, to advance the therapy into phase III clinical trials.

Endometriosis affects an estimated 190 million women worldwide and is a leading cause of chronic pelvic pain and infertility. The condition significantly impacts quality of life, with symptoms including severe menstrual pain, pain during intercourse, and reproductive challenges.

Hope Medicine stated that it aims to accelerate the development of HMI-115 to bring a safer and more effective treatment option to patients globally.