AT402Z / Atossa Therap - LARVOL DELTA

Novel (Z)-endoxifen-related new chemical entities exhibit potent anti-cancer activity in ERα+ breast cancer. (PubMed, NPJ Breast Cancer) - "(Z)-Endoxifen (ENDX), the most abundant active metabolite of tamoxifen, is a potent, orally bioavailable, selective estrogen receptor modulator currently in development for breast health indications. During its synthesis, structurally related compounds are generated as byproducts termed here as new chemical entities (NCEs): AT416E, AT416Z, AT402E, AT402Z, and AT300, which have not been previously studied...Some NCEs also combined favorably with abemaciclib, producing additive to synergistic effects comparable to or greater than ENDX. Together, our findings support further investigation of select NCEs for ERα-positive breast cancer, particularly for tumors with ESR1 activating mutations and as potential second- or third-line options for recurrent disease."

Journal • Breast Cancer • Estrogen Receptor Positive Breast Cancer • Hormone Receptor Breast Cancer • Oncology • Solid Tumor

Novel (Z)-endoxifen-related chemical entities exhibit potent anti-cancer activity in ERα+ breast cancer (AACR 2025) - "(Z)-Endoxifen (ENDX), an active metabolite of tamoxifen, is a potent, orally bioavailable selective estrogen receptor modulator with a favorable safety profile now under development for breast health applications. Its synthesis yields endoxifen-related byproducts that are new chemical entities (NCEs), including AT416E, AT416Z, AT402E and AT402Z...These findings highlight four NCEs with notable anti-cancer activity, with some matching or surpassing ENDX in several cancer-relevant cellular readouts, marking them as novel candidates for ERα+ breast cancer therapy. Further studies will advance one or more of these NCEs into in vivo models to confirm their therapeutic efficacy and potential for clinical application."

Breast Cancer • Hormone Receptor Breast Cancer • Oncology • Solid Tumor