H3B-8800

H3B-8800 is an orally bioavailable, investigational small molecule that acts as a splicing modulator by inhibiting the splicing factor 3B subunit 1 (SF3B1), a core component of the spliceosome complex. SF3B1 is frequently mutated in various cancers, including myeloid malignancies such as acute myelogenous leukemia and chronic myelomonocytic leukemia. H3B-8800 binds to and blocks SF3B1 activity, leading to modulation of pre-mRNA processing—specifically inducing retention of short, GC-rich introns and promoting nonsense-mediated decay of aberrant mRNAs. This mechanism results in preferential lethality for cancer cells harboring spliceosome mutations while sparing normal cells. The drug was developed by H3 Biomedicine and has been granted orphan drug status by the FDA; it remains under clinical investigation for hematologic malignancies[1][2][5][6][7].