To determine whether fimepinostat efficiently kills human SCLC cell lines we determined the LD50 dose of fimepinostat in four established cell lines representative of the recently described neuroendocrine subgroups of SCLC defined by ASCL1 or NEUROD1 expression [17] (SCLC-N: NCI-H82. The gene discussed is NEUROD1; the disease is small cell lung carcinoma.