Since a large subset of SCLCs are characterized by high BCL-xL and BCL-2 mRNA and protein expression, we evaluated 753b in comparison to DT2216, navitoclax, and DT2216 + venetoclax combination in terms of efficiency and specificity for BCL-xL and BCL-2 degradation, as well as the viability of SCLC cells. The gene discussed is BCL2; the disease is small cell lung carcinoma.