Actinium reports data on anti-tumor effects of HER3-targeted radiotherapy

Actinium Pharmaceuticals announces encouraging preclinical proof of concept data at a poster presentation at the American Association for Cancer Research, or AACR, annual Meeting being held April 14-19 in Orlando, Florida. The poster showcased the robust anti-tumor effects of HER3-targeted radiotherapy using multiple therapeutic radionuclides in preclinical models of high unmet need malignancies. Highlights from the AACR poster titled, "Novel HER3 targeting antibody radioconjugates, 225Ac-HER3 ARC and 177Lu-HER3 ARC, exhibit potent antitumor efficacy in HER3-positive solid tumors" include: Actinium’s HER3-targeted radiotherapy displayed strong anticancer activity when conjugated to either alpha-emitting Actinium-225 or beta-emitting Lutetium-177 in models of two high unmet need cancers, highlighting its therapeutic potential for HER3+ malignancies; HER3-ARC showed strong target engagement and efficient cellular internalization with compelling cytotoxic activity against established in vitro cellular models; A single dose of HER3-ARC, conjugated to either Actinium-225 or Lutetium-177 showed highly significant reductions in tumor burden in a preclinical ovarian cancer model compared to bevacizumab, an anti-VEGF monoclonal antibody indicated in ovarian cancer; Promising antitumor activity displayed in a preclinical model of colorectal cancer, a highly aggressive malignancy, including a significant reduction in tumor volume when dosed with 225Ac-HER3-ARC; and the consistent overexpression of HER3 in multiple solid tumor types including ovarian, renal, prostate, urothelial, breast, and lung cancers suggests broad utility of a HER3-targeted agent across oncology indications.