Atossa Therapeutics’ Endoxifen shows breast cancer risk prevention in trial

Atossa Therapeutics (ATOS) announced the publication of results from the KARISMA Endoxifen trial in the Journal of the National Cancer Institute. The Phase 2 study evaluated daily oral Endoxifen and demonstrated that low-dose Endoxifen significantly reduced MBD, a key risk factor for breast cancer. The article highlighted data from a study funded by Atossa. The study evaluated placebo, 1 mg, and 2 mg Endoxifen administered daily for six months in 240 healthy premenopausal women enrolled through the Swedish national mammography screening program. Elevated MBD is an established risk factor for breast cancer and a recognized pharmacodynamic marker of response to endocrine risk-reduction therapy. In the KARISMA Endoxifen trial, both the 1 mg and 2 mg Endoxifen dose levels produced statistically significant reductions in MBD compared with placebo. The 1 mg dose reduced MBD by 19.3% vs. placebo, while the 2 mg dose reduced MBD by 26.5% vs. placebo. These reductions were comparable to those previously reported with standard-dose tamoxifen, but were achieved using direct administration of Endoxifen, the most therapeutically active metabolite of tamoxifen. Both levels demonstrated a favorable tolerability profile. Adverse events were generally vasomotor in nature, consistent with those previously reported for tamoxifen.