SB-4826

SB-4826 is a **first-in-class, orally bioavailable, covalent small molecule inhibitor** of the SUMO activating enzyme (**SUMO E1**), also known as SUMO1 activating enzyme subunit 1 (SAE1)[1][3][5][7][9]. It selectively and irreversibly binds to an allosteric pocket on SUMO E1, specifically targeting cysteine-30, resulting in highly selective inhibition of global cellular sumoylation[1][5]. SB-4826 blocks proliferation across a broad panel of over 100 cancer cell lines and demonstrates potent anti-tumor activity in preclinical in vivo models, with increased effectiveness both as monotherapy and in combination with immune checkpoint blockade (e.g., anti-PD-1, rituximab)[1][3][5]. SB-4826 induces dose- and time-dependent Type I interferon (IFN) signaling, increases CD8+ T cell infiltration, and modulates the tumor microenvironment to boost anti-tumor immunity[1][3][5]. It is being investigated for hematological malignancies and solid tumors, with particular focus on lymphoma (including follicular lymphoma)[3][8]. SB-4826 is uniquely positioned as an oral therapy with covalent, allosteric mechanism, distinguishing it from previous SUMO E1 inhibitors like TAK-981[1][5][9].