Radioimmunotherapy with α-Particle Emitting Radioimmunoconjugates

Abstract

Radionuclides which decay by the emission of α-particles are attractive for certain radioimmunotherapeutic applications. These include the treatment of lymphomas, compartmentally spread malignancies such as ovarian cancer and neoplastic meningitis, and micrometastatic disease. Two α-emitting radionuclides of interest for this purpose are ²¹²Bi (60.6 min half life) and ²¹²At (7.2 hr half life). Compared with the β-emitters commonly used for radiotherapy, the α-particles of ²¹²Bi and ²¹²At are of higher energy, much shorter range (less than 100 μm), and considerably higher linear energy transfer. Preliminary results obtained in a variety of in vitro systems and in vivo models have documented the exquisite toxicity of α-particles and have established a basis for initiating radiotherapy trials in humans with monoclonal antibodies labeled with α-emitting radionuclides