SIAIS056 effectively degraded various clinically significant resistance BCR-ABL (DC50 = 0.18 nM; for DAS-6–2-2–6-CRBN: DC50 = 30.5 nM) mutations and demonstrated strong tumour regression in K562 xenograft models (IC50 = 0.49 nM; for dasatinib: IC50 = 0.9 nM; for DAS-6–2-2–6-CRBN: 4.1 nM). The gene discussed is BCR; the disease is neoplasm.