Pipendoxifene, also known as ERA-923, is a new antiestrogen with potential anticancer activity. ERA-923 potently inhibits estrogen binding to ER-alpha (IC50 = 14 nM). In ER-alpha-positive human MCF-7 breast carcinoma cells, ERA-923 inhibits estrogen-stimulated growth (IC50 = 0.2 nM) associated with cytostasis. In vitro, a MCF-7 variant with inherent resistance to tamoxifen (10-fold) or 4-OH tamoxifen (>1000-fold) retains complete sensitivity to ERA-923 . In preclinical models, ERA-923 has an improved efficacy and safety compared with tamoxifen. In the combination with temsirolimus, ERA-923 showed excellent anticancer activity in preclinical models.
SS148 is an nsp14 nsp16 MTase inhibitor. It also showed some degree of selectivity against human protein MTases, an indication of great potential for chemical optimization towards more potent and selective inhibitors of coronavirus MTases.