To establish the optimal ratio of drug combination to be used in a cell culture model of SOD1-associated ALS, a 3D checkerboard assay was employed to test varying concentrations of CuATSM (0–0.5 μM), ebselen (0–20 μM) and telbivudine (0–500 μM on the survival of neuronal-like NSC-34 cells expressing SOD1G93A-EGFP (Fig. 1a and Supplementary Table S1). Here, SOD1 is linked to amyotrophic lateral sclerosis.