[en] A significant step towards demonstrating the feasibility of coupling Lower Hybrid (LH) waves in ITER has been achieved in the latest LH current drive experiments in JET. The local electron density in front of the LH launcher was increased by injecting gas (D₂ or CD₄) from a dedicated gas injection module magnetically connected to the launcher. P(LHCD) = 3 MW was coupled with an average reflection coefficient of 5%, at a distance between the last closed flux surface and the launcher of 10 cm, in plasmas with an internal transport barrier (ITB) and H-mode edge, with type 1 and type 3 ELMs (edge localized modes). Following a modification of the gas injection system, in order to optimise the gas localisation with respect to the LH launcher, injection of D₂ proved to be more efficient than CD₄. A D₂ flux of 5-8 x 10²¹ el/s was required at 9 cm. The plasma performance (neutron rate, H-factor, ion temperature) was similar with D₂ and CD₄. An additional advantage with D₂ injection was found, as it reduced the amplitude of the ELMs, which further facilitated the LH coupling. Furthermore, preliminary results of the study of the behaviour of electron density profile in the scrape-off layer during injection of C₂H₆ and C₃H₈ are reported. Finally, the appearance of hot spots, resulting from parasitic absorption of LHCD power in front of the launcher mouth, was studied in the long distance discharges with near gas injection. (authors)