Thus, using a ‘Double-Hit method’ that integrates single-cell transcriptomics (scRNAseq) and pharmacogenomics-guided computational prediction (secDrug), we predicted that FK866 (NAMPT inhibitor) targets the majority of the PCa single cells representing cancer stemness, drug resistance, aggressiveness/CRPC, AR receptor or neuroendocrine status, and is, therefore, a top drug candidate potentially effective against most lethal forms of PCa. The gene discussed is NAMPT; the disease is cancer.