Actinium Pharmaceuticals, Inc. and EpicentRx, Inc. announced that they have entered into a research collaboration to study Actinium's Actimab-A targeted radiotherapy in combination with RRx-001, EpicentRx's novel small molecule immunotherapy targeting the CD47-SIRPa axis. Under this strategic research collaboration, the two companies will work to determine the benefit of combining Actinium's targeted radiotherapy with EpicentRx's RRx-001, which are both clinical stage drug candidates, in acute myeloid leukemia (AML). CD47 is a macrophage checkpoint upregulated in certain cancers that acts as a "don't eat me" signal on cancer cells to suppress phagocytosis and evade detection and destruction by the immune system.

EpicentRx's RRx-001, currently under investigation in a Phase 3 trial for Small Cell Lung Cancer and in other oncology and non-oncology indications, is a versatile next generation small molecule immunotherapeutic that targets the CD47-SIRPa axis and the NLRP3 inflammasome to alter the tumor microenvironment and optimize immune response. Actinium's targeted radiotherapies have shown the ability to upregulate the cell surface "eat me" signal calreticulin, which can result in anti-tumor immune response. This collaboration will explore the mechanistic synergy of RRx-001's CD47–SIRPa downregulation with Actinium's targeted radiotherapy calreticulin upregulation to increase the immune detection and destruction of cancer cells and their potential to improve patient outcomes.

Actinium's clinical pipeline of targeted radiotherapies, referred to as Antibody Radiation-Conjugates (ARCs), includes Iomab-B and Actimab-A. Collectively, Actinium's ARCs have been studied in nearly 600 patients at leading comprehensive cancer centers including the pivotal Phase 3 SIERRA trial for Iomab-B, which completed patient enrollment in September 2021. Actimab-A has been studied extensively as a single agent and in combination with chemotherapy and targeted agents in approximately 150 patients with AML in Phase 1 and 2 trials. Underpinning Actinium's clinical pipeline is its AWE technology platform, which applies Actinium's extensive intellectual property portfolio of over 160 issued and pending patents, R&D capabilities and know-how to the development of targeted radiotherapies exploiting multiple different radioisotope payloads including the potent alpha-emitter, Actinium-225.

Actinium's R&D efforts employ a multidisciplinary approach leveraging its team's expertise and experience in cancer cell biology, radiochemistry, radiation sciences, immunology and oncology drug development. Actinium has utilized its AWE technology platform to create a CD38 targeting ARC using the blockbuster myeloma antibody daratumumab (Darzalex®) and it is also being utilized in collaboration with Astellas Pharma, to create theranostics for solid tumors.