Clinical-stage biopharmaceutical company Atossa Therapeutics Inc (Nasdaq:ATOS) announced on Tuesday that it has been granted US Patent No. 12,275,684, expanding its intellectual property portfolio for (Z)-endoxifen, a Selective Estrogen Receptor Modulator.

The patent covers enteric oral formulations of (Z)-endoxifen and their use in treating hormone-dependent breast and reproductive tract disorders.

This addition strengthens Atossa Therapeutics' existing patent estate, which includes multiple US patents and more than 100 claims related to (Z)-endoxifen compositions and clinical applications. The company is focused on advancing targeted therapies for hormone receptor-positive breast cancer.

(Z)-endoxifen is designed to inhibit estrogen receptors, degrade them, and target the oncogenic protein PKCβ1 at clinically relevant concentrations. It has demonstrated efficacy in patients resistant to standard hormonal therapies and shows favorable bone and endometrial safety profiles compared to tamoxifen.

Atossa Therapeutics is developing an oral, enteric-coated version of (Z)-endoxifen to preserve its potency by avoiding stomach acid-induced conversion to the inactive (E)-endoxifen. Clinical studies indicate the formulation is well tolerated in both cancer and non-cancer populations.

The company is currently evaluating (Z)-endoxifen for both treatment and prevention of breast cancer, including ongoing studies in metastatic breast cancer.