Actinium Pharmaceuticals Highlights Potent Anti-Tumor Activity of a HER3 Targeted Radiotherapy at AACR

Actinium Pharmaceuticals, Inc. (NYSE AMERICAN: ATNM), has announced positive results from preclinical studies evaluating an anti-HER3 antibody, conjugated with an Actinium-225 (Ac-225) radioisotope payload, for targeting HER3-positive non-small cell lung cancer (NSCLC) cells.

These data were presented at the American Association of Cancer Research (AACR 2022) annual meeting, which is being held April 8th – 13th at the Ernest N. Morial Convention Center in New Orleans, Louisiana.

Dr. Helen Kotanides, Vice President, Translational Research and Preclinical Development, stated, “HER3 is a well-validated target that is overexpressed in a number of cancers and associated with poor survival in breast, ovarian, lung, gastric and prostate cancer. It is also upregulated in response to HER1 and HER2 targeted therapies as part of acquired resistance against these EGFR therapies. These data show that arming a HER3-targeting agent with Actinium-225 results in potent anti-tumor agent, which improved survival in our NSCLC models. These data support our goal of developing a HER3 targeted radiotherapy for use in a patient population in need of new treatments and give us great excitement for our ongoing collaboration with AVEO centered around HER3.”

Sandesh Seth, Chairman and CEO of Actinium, stated, “We are excited to continue to demonstrate Actinium’s enhanced R&D capabilities and commitment to developing potent radiotherapies targeting solid tumors. We look forward to sharing these data, which show the efficacy for our novel approach of conjugating Actinium-225 to a HER3 antibody at AACR 2022. The development of Ac-225-HER3-ARC, a product of our validated Antibody Warhead Enabling (AWE) technology platform, represents a departure from conventional HER3-targeting approaches, such as naked antibodies and antibody drug conjugates, that are currently being explored for this tumor antigen. These exciting data highlight Actinium’s leadership in developing novel targeted radiotherapy approaches for treating cancers having high unmet needs.”