ATNM Lawsuit Alert! Class Action Lawsuit Against Actinium Pharmaceuticals

A class action lawsuit was filed against Actinium Pharmaceuticals (ATNM) by Levi & Korsinsky on March 27, 2025. The plaintiffs (shareholders) alleged that they bought ATNM stock at artificially inflated prices between October 31, 2022, and August 2, 2024 (Class Period) and are now seeking compensation for their financial losses. Investors who bought Actinium Pharmaceuticals stock during that period can click here to learn about joining the lawsuit.

Actinium Pharmaceuticals is a biopharmaceutical company focused on developing Antibody Radiation Conjugates (ARCs) and other targeted radiotherapies, designed to improve outcomes for people who have failed existing oncology therapies. 

The company’s tall claims about its lead product candidate, Iomab-B, are at the heart of the current complaint. Iomab-B is an experimental radiotherapy, licensed from the Fred Hutchinson Cancer Research Center, which is intended (upon approval) to prepare patients with a less toxic way for bone marrow transplants, instead of the current preparation requiring chemotherapy and radiation treatments.

Actinium Pharmaceuticals’ Misleading Claims

According to the lawsuit, Actinium and three of its senior executives and/or directors (the Management Defendants) and a member of its Scientific Advisory Board (the Individual Defendant) repeatedly made false and misleading public statements throughout the Class Period. Particularly, they are accused of omitting truthful information about the likelihood of its Biologics License Application (BLA) for lomab-B being approved, and ancillary issues, from SEC filings and related material.

For instance, during the Class Period, the defendants repeatedly boasted about the positive topline results from Iomab-B’s ongoing Sierra trial. Notably, the trial met its primary endpoint of durable Comple Remission (dCR) for 6 months, along with the required statistical significance. Consequently, Actinium informed that it planned to submit a BLA seeking approval for Iomab-B.

Additionally, in a presentation related to the 64th Annual American Society of Hematology (ASH) Meeting, the company noted that Iomab-B displayed a significantly improved event-free survival, a secondary endpoint, with a hazard ratio of 0.22 and median overall survival (mOS) had doubled.

Finally, during a special call held on February 28, 2023, the defendants stated that Sierra trial had met the primary endpoint of durable complete remission along with high statistical significance, which was designed and required by the U.S. Food and Drug Administration (FDA).

However, subsequent events (discussed below) revealed that Actinium had misled investors about the expected BLA approval for Iomab-B from the FDA.

Plaintiffs’ Arguments

The plaintiffs maintain that the defendants deceived investors by lying and withholding critical information about the business practices and prospects during the Class Period. Importantly, the defendants are accused of misleading investors about the company’s expectations for and commercialization prospects of Iomab-B.

The information became clear before the market opened on August 5, 2024, when Actinium issued a press release updating investors about the status of the BLA filing and future prospects of Iomab-B in the U.S. The company mentioned that it had concluded interactions with the FDA regarding the clinical and Chemistry, Manufacturing and Controls aspects of Iomab-B’s BLA.

Furthermore, the FDA determined that despite Actinium’s claims, the analyses from the Sierra trial did not adequately support a BLA filing for Iomab-B, and required an additional clinical study. Following the news, ATNM stock plunged 59.8% on the same day.

To conclude, the defendants allegedly misled investors regarding the positive results of its Sierra trial, the FDA’s approval of its BLA filing, and the subsequent commercialization prospects of Iomab-B. Owing to these issues, ATNM stock has lost 81.5% in the past year, causing massive damage to shareholder returns.