While NKTR-255 and the naked rhIL-15 showed similar in vitro properties, mainly affinity and signaling biology, the polymer conjugate presented an enhanced pharmacokinetic profile that led to potent immune responses with significant antitumor effects and increased survivals in lymphoma-bearing mice [77] and in a humanized multiple myeloma mouse model in combination with daratumumab [78], enhancing the effectiveness of CD19-targeted CAR-T therapies [79]. The gene discussed is CD19; the disease is plasma cell myeloma.