Bel-sar (belzupacap sarotalocan) is a first-in-class virus-like drug conjugate composed of a tumor-targeting virus-like particle linked to a photoactivatable dye, inducing proimmunogenic tumor cell death and antitumor immune response...Bel-sar demonstrated focal administration feasibility, a favorable safety profile, and encouraging preliminary efficacy in NMIBC, with robust immune activation in treated and untreated tumors. These findings support bel-sar's continued development as a therapy combining local tumor eradication with durable immune surveillance.