Atossa Therapeutics, Inc. announced an expanded research agreement with Weill Cornell Medicine to explore the potential synergy between antibody drug conjugates (ADCs) and (Z)-endoxifen. The expanded research agreement with Weill Cornell will build on previously conducted in silico research that determined a strong clinically relevant anti-tumor effect when combining ADCs and (Z)-endoxifen. Specifically, the artificial intelligence modeling showed that the combination of (Z)-endoxifen with ADCs will enhance the pro-apoptotic effects seen after administration of either therapy alone.

This computer-based analysis was further validated by previously published preclinical studies looking at the effect of selective estrogen receptor modulator (SERM) and chemotherapy combination strategies. Seven key opinion leaders also confirmed the strong scientific rationale and proposed efficacy of combining (Z)-endoxifen with ADCs in patients with advanced breast cancer. ADCs are a specially designed class of therapeutics that target cancer cells expressing specific antigens using directed antibody-drug delivery.

The therapies bind to targets on the cell, causing the release of a cytotoxic drug designed to kill the cancer cell. The Weill Cornell research will focus on the combination of (Z) -endoxifen and two FDA-approved ADCs, TRODELVY and ENHERTU. Both are currently approved as monotherapies to treat metastatic breast cancer.

Additionally, TRODELVY is approved to treat adults with metastatic bladder and urinary tract cancers. (Z)-endoxifen is the most potent Selective Estrogen Receptor Modulator (SERM) for estrogen receptor inhibition and also causes estrogen receptor degradation. It has also been shown to have efficacy in the setting of patients with tumor resistance to other hormonal treatments.

In addition to its potent anti-estrogen effects, (Z)-endoxifen has been shown to target PKCß1, a known oncogenic protein, at clinically attainable blood concentrations. Finally, (Z)-endoxifen appears to deliver similar or even greater bone agonistic effects while resulting in little or no endometrial proliferative effects compared with standard treatments, like tamoxifen. Atossa is developing a proprietary oral formulation of (Z)-endoxifen 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 significant proportion of (Z)-endoxifen to the inactive (E)-endoxifen.

Atossa?s (Z)-endoxifen has been shown to be well tolerated in Phase 1 studies and in a small Phase 2 study of women with breast cancer. (Z)-endoxifen is currently being studied in four Phase 2 trials: one in healthy women with measurable breast density, one in women diagnosed with ductal carcinoma in situ, and two other studies including the EVANGELINE study in women with ER+/HER2- breast cancer. Atossa?s (Z)-endoxifen is protected by three issued U.S. patents and numerous pending patent applications.