Response, PFS, and OS for patients treated with daratumumab combined with ATRA at the RP2D. (A) Response, (B) PFS-B, and (C) OS-B for all patients treated with daratumumab combined with ATRA at the RP2D of 45 mg/m². (D) PFS-AB and (E) OS-AB for the whole treatment strategy of daratumumab monotherapy followed by the daratumumab/ATRA combination for all patients treated at the RP2D.