Compounds, compositions and kits to increase precise genome editing efficiency in eukaryotic cells or organisms. Combinations of at least two compounds selected from: (a) HDAC inhibitor, preferably Trichostatin A, (b) NAE inhibitor, preferably MLN4924 (c) DNA-PK inhibitor, preferably NU7026 and, (d) RPA inhibitor, preferably NSC15520. Use of a catalytically inactive mutant of DNA protein kinase catalytic subunit (DNA-PKcs) K3753R, to enhance genome editing, optionally, combined with one or more of (a) to (d).