Continuing progress in radioimmunotherapy for hematologic malignancies

Radioimmunotherapy (RIT) involves combining a cytotoxic radionuclide with an antibody (Ab) targeting a tumor antigen. Compared with conventional therapies, RIT improves the therapeutic efficacy of Ab and ameliorates toxicity. This comprehensive review describes the current advancements and future prospects in RIT for treating hematologic malignancies based on recent investigations. Although β-particle RITs targeting CD20 are effective with low toxicity in patients with relapsed/refractory indolent or transformed non-Hodgkin's lymphoma, these treatments have not gained popularity because of the increasing availability of new therapies. RIT using single-domain antibodies is expected to improve tumor penetrance and reduce radiation exposure to non-target organs. To enhance RIT efficacy, α-particle RIT and pretargeted radioimmunotherapy (PRIT) are currently being developed. Alpha-particle RIT demonstrates substantial antitumor activity and reduced bystander effects due to its high linear energy transfer and short particle range. PRIT may increase the tumor-to-whole body dose ratio.