A precision approach to the molecular drivers of endometriosis.

Endometriosis is a chronic, systemic disease in which tissue resembling the uterine lining grows outside the uterus — most commonly on the pelvic peritoneum, ovaries, and other organs. These ectopic lesions establish their own pathological microenvironment, supported by aberrant local hormonal signaling and chronic inflammation.

A central feature of endometriotic lesions is their ability to produce estrogen locally, independent of the body's normal endocrine regulation. This local estrogen production drives lesion growth, sustains inflammation, and helps explain why systemic hormonal suppression — even when it works — only partially addresses the disease.

The molecular details of how lesions sustain themselves point to specific, druggable nodes that current therapies do not engage.

First-line care for endometriosis is dominated by combined hormonal contraceptives, progestins, and GnRH-axis modulators. These therapies aim to lower systemic estrogen exposure and quiet the ovaries, but they act on the entire endocrine system rather than on the disease itself.

The consequences are well-documented: bone-density loss, vasomotor symptoms, mood and metabolic effects, and limits on duration of use that are particularly difficult for women in reproductive years. Even when symptoms improve, the underlying lesion biology is not addressed, and recurrence after discontinuation is common.

Surgical excision can provide meaningful relief, but it is invasive, technically demanding, and carries a high rate of disease recurrence. There is a clear unmet need for a therapy that intervenes at the level of the lesion biology — without imposing a system-wide endocrine cost.

Esma Bio is developing an RNA-based, lesion-selective therapeutic designed to act within endometriotic lesions — silencing the local drivers of estrogen production that sustain them, while preserving normal systemic endocrine function.