Status of the measurement of K S -> {pi}e{ u} branching ratio and lepton charge asymmetry with the KLOE detector

We present the current status of the analysis of about 1.7 billion K_S K_L pair events collected at DA{Phi}NE with the KLOE detector to determine the branching ratio of K_S -> {pi}e{ u} decay and the lepton charge asymmetry. This sample is ~4 times larger in statistics than the one used in the previous most precise result, from KLOE as well, allowing us to improve the accuracy on the measurement and related tests of CPT symmetry and Delta S = Delta Q rule.