SLBST Pharma Inc. seeks to address the pain of endometriosis by repurposing a 60-year-old drug as the first non-hormonal, well-tolerated, long-term treatment. The company holds issued US and European patents for the use of hydroxychloroquine (HCQ) to treat endometriosis. HCQ has an excellent six-decade safety record among the tens of millions of patients who've used it for lupus (SLE) and rheumatoid arthritis (RA). Roughly one-in-ten women of childbearing age suffer from endo, representing over 20M women between the US and Europe. Two-thirds of women taking the existing hormonal treatments for endo express dissatisfaction. There is a large unmet need for an endo treatment compatible with conception and pregnancy (which HCQ is). Following consultation with the FDA in early 2022, the company is preparing an IND application to begin a Phase 2b clinical trial in the spring of 2023.