Actinium Pharmaceuticals Announces Clinical Trial Program in Solid Tumors Combining Actimab-A with PD-1 Checkpoint Inhibitors KEYTRUDA® and OPDIVO®

Core Insights - Actinium Pharmaceuticals is conducting clinical trials to evaluate the efficacy of Actimab-A in combination with PD-1 inhibitors KEYTRUDA® and OPDIVO® to improve patient outcomes in solid tumors [1][4][6] - The trials are based on the premise that Actimab-A can selectively target and deplete Myeloid Derived Suppressor Cells (MDSCs) that express the CD33 antigen, which are known to limit the effectiveness of PD-1 inhibitors [1][2][3] - Initial proof of concept data from these trials is expected in 2025, potentially opening a multi-billion-dollar market opportunity for Actimab-A [1][4][6] Company Overview - Actinium Pharmaceuticals is a pioneer in targeted radiotherapies, focusing on improving patient outcomes through innovative treatments [7] - Actimab-A, the company's lead product, utilizes Actinium-225, a potent alpha-emitter radioisotope, to induce lethal DNA damage in targeted cells [3][7] - The company is also advancing Actimab-A in acute myeloid leukemia (AML) and other myeloid malignancies, with promising results in clinical trials [7] Clinical Trials and Strategy - The solid tumor program includes head-to-head trials comparing Actimab-A combined with KEYTRUDA® or OPDIVO® against the respective PD-1 inhibitors alone [4][6] - Targeted tumors include Head and Neck Squamous Cell Carcinoma (HNSCC) and Non-Small Cell Lung Cancer (NSCLC), with trials focusing on adults with PD-L1 expression [4] - Key endpoints for the trials include Overall Response Rate (ORR), Progression Free Survival (PFS), and Overall Survival (OS), along with biomarker data on CD33+ MDSC depletion and T-Cell activity [4] Market Potential - The combination therapy approach aims to address the unmet needs of patients whose cancers progress despite PD-1 checkpoint inhibitors, representing a treatment population exceeding 500,000 patients [6][7] - The potential market for Actimab-A as a combination therapy with PD-1 inhibitors is estimated to be multi-billion dollars, highlighting its significance in the oncology landscape [1][6][7]