Clinical Studies with Bismuth-213 and Actinium-225 for Hematologic Malignancies.

Clinical Studies with Bismuth-213 and Actinium-225 for Hematologic Malignancies. Curr Radiopharm. 2018 May 24;: Authors: Jurcic JG Abstract Because α-particles have a shorter range and a higher linear energy transfer compared to β-particles, targeted α-particle therapy offers the potential for more efficient tumor cell killing while sparing surrounding normal cells. To date, clinical studies of α-particle therapy for acute myeloid leukemia (AML) have focused on targeting the cell surface antigen CD33 using the humanized monoclonal antibody lintuzumab. An initial phase I study showed the safety feasibility, and anti-leukemic effects of bismuth-213 (213Bi)-labeled lintuzumab. Subsequently, 213Bi-lintuzumab was found to produce remissions in AML after partial cytoreduction with cytarabine. The 46-minute half-life of 213Bi, however, limits its widespread use. Therefore, a second-generation construct using actinium-225 (225Ac), a radiometal that generates four α-particle emissions, was developed. A phase I trial demonstrated that a single infusion of 225Ac-lintuzumab was safe at doses of 111 kBq/kg or less and has anti-leukemic activity. In a second phase I study, objective responses were seen in 28% of older patients with untreated AML after treatment with fractionated-dose 225Ac-lintuzumab and low-cytarabine. A phase II study of 225Ac-lintuzumab monotherapy in this population is now in progress and is also being studied in a subset...
Source: Current Radiopharmaceuticals - Category: Radiology Tags: Curr Radiopharm Source Type: research