Dienogest interrupts the chemokine signalling axis in endometriotic lesions with resistant signatures providing novel opportunities for personalised treatment.

Progestins are important first line and adjuvant medications for endometriosis, yet their efficacy varies among patients. Dienogest (DNG), a 4th generation progestin, is one of the most prescribed and successful progestins, although a subset of patients remain refractory to treatment. A prospective method to match patients to DNG, or other treatments could significantly improve patient outcomes. We employed a multidisciplinary approach using archival patient samples, clinical data, single nuclei sequencing, in silico prediction and high-content organoid drug screening to investigate DNG's impact on endometriotic lesions, signatures of non-response, and treatment options for refractory patients. We found DNG represses the inflammatory phenotype of deeply infiltrating endometriotic lesions by disrupting the chemokine signalling axis. Refractory patients displayed altered epithelial and stromal cell composition, aberrant progesterone receptor co-repressor signalling and enhanced TGF-B mediated fibrosis. Computational drug predictions identified potential therapies for refractory cases, including glucocorticoid receptor agonists for stroma- and immune-rich lesions, and HSP90 or NF-κB inhibitors for epithelial-dominant lesions, the activity of which were validated in high content screening of patient derived organoids. Notably some progestins already approved for endometriosis management possess off-target glucocorticoid activity, providing immediate potential for personalized treatment selection.