Atossa Therapeutics, Inc. announced that 170 patients have been enrolled in the Company's ongoing Phase 2 Karisma-Endoxifen clinical trial. Atossa expects the study to fully enroll in the fourth quarter of 2023. The Karisma-Endoxifan trial is a randomized, double-blind, placebo-controlled efficacy study of oral (Z) -endoxifen in premenopausal women with measurable breast density.

Participants receive daily doses of (Z) -endoxIFen for six months, over the course of which mammograms are conducted to measure reduction in mammographic breast density (MBD). Participants will also have a mammogram at 24 months to assess the durability of the MBD changes. Women with the highest density are four to six times more likely to get breast cancer than women with the least dense breasts.

(Z)-endoxifen is the most active metabolite of the FDA approved Selective Estrogen Receptor Modulator (SERM), tamoxifen. Studies by others have demonstrated that the therapeutic effects of tamoxifen are driven in a concentration-dependent manner by (Z)-endoxifan. In addition to its potent anti-estrogen effects, (Z)-endoxifEN at higher concentrations has been shown to target PKCb1, a known oncogenic protein.

Atossa is developing a proprietary oral formulation of (Z)-endoxif En that does not require liver metabolism to achieve therapeutic concentrations and is encapsulated to bypass the stomach as acidic conditions in the stomach convert a greater proportion of (Z)-endoxIFen to the inactive (E)-endoxifen. Atossa's (Z)-endoxifin is protected by three issued U.S. patents and numerous pending patent applications.