Preventive new RSV vaccines and/or therapeutic anti-RSV monoclonal antibodies are available . However, no complementary anti-RSV small molecules for therapeutic use are yet clinically available . Despite the identification of numerous and potent in vitro anti-RSV fusion inhibitors, the emergence of resistance mutations together with pharmacological issues, has prevented their clinical use . New small-drugs are required to therapeutically overcome most of the resistant mutations implicated in RSV fusion .