Overview

A class action lawsuit has been filed against Actinium Pharmaceuticals, Inc. (“Actinium” or the “Company”) and certain of the Company’s current senior executive officers alleging violations of the federal securities laws.  The Company’s common stock trades on the New York Stock Exchange under the symbol “ATNM.”

The Actinium class action lawsuit was brought on behalf of all persons and entities who purchased or otherwise acquired Actinium securities between October 31, 2022, and August 2, 2024, both dates inclusive (the “Class Period”).

Actinium is a late-stage biopharmaceutical company that develops targeted radiotherapies, such as Iomab-B, to treat people who have failed existing oncology therapies.  Iomab-B is an induction-and-conditioning agent used before bone marrow transplants and has the potential to treat elderly relapsed or refractory (“R/R”) acute myeloid leukemia (“AML”) (collectively, “R/R AML”).  Actinium evaluated Iomab-B in the pivotal Phase 3 Sierra trial (the “Sierra Trial”), where the drug met the primary endpoint of durable Complete Remission (“DCR”) with statistical significance (p<0.0001).

In the context of the Sierra Trial, DCR measured whether the patient remained in complete remission (i.e., the disappearance of all signs of cancer in response to treatment) for longer than six months from the date of bone marrow sampling, which is a procedure that involves removing a small sample of bone marrow for examination under a microscope.  DCR does not measure the duration of time the patient remains alive after treatment, which is typically referred to as “Overall Survival” or “OS.”  Overall Survival was one of the Sierra Trial’s two key secondary endpoints.  The Sierra Trial did not meet its OS key secondary endpoint.  According to agency guidance concerning acute myeloid leukemia (“AML”) issued by the U.S. Food and Drug Administration (“FDA”), the FDA has accepted OS, but not DCR, as a clinical endpoint that demonstrates clinical benefit for approval of new AML treatments.

The Actinium class action lawsuit alleges that Defendants, throughout the Class Period, made materially false and misleading statements that conditioned investors to believe that there was a very high likelihood that the FDA would review and approve Actinium’s Biologics License Application (“BLA”) for Iomab-B.  Specifically, Defendants (1) repeatedly touted the Sierra Trial’s positive DCR data while downplaying the study’s failure to generate statistically significant or clinically meaningful Overall Survival data; and (2) misled investors about the importance of the Sierra Trial’s poor Overall Survival data by claiming that the FDA had somehow blessed the design of the Sierra Trial such that the lack of statistically significant or clinically meaningful OS data would not be a barrier to approval of the BLA.

Furthermore, the Actinium class action lawsuit alleges that Defendants made materially false and/or misleading statements, as well as failing to disclose material adverse facts about the Company’s business, operations, and prospects.  Specifically, Defendants failed to disclose that: (1) the Company’s data from the Sierra Trial was unlikely to satisfy the FDA’s guidelines for the acceptance and approval of the Company’s Iomab-B BLA; (2) the additional analyses, including long-term follow-ups that purportedly demonstrated a trend towards improved Overall Survival that the Company provided to the FDA in an attempt to mitigate the Sierra Trial’s poor OS data, were unlikely to satisfy the FDA’s guidelines for the acceptance and approval of the Company’s Iomab-B BLA; (3) as a result, the FDA would likely refuse to review the Iomab-B BLA or, if it did consider that BLA, that the application in its current form was unlikely to be approved; and (4) as a result, Defendants’ positive statements about the Company’s business, operations, and prospects were materially misleading and/or lacked a reasonable basis.

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If you purchased or otherwise acquired Actinium securities between October 31, 2022, and August 2, 2024, both dates inclusive, and you wish to serve as lead plaintiff in this lawsuit, we encourage you to submit your information to DiCello Levitt LLP via the form on this page. 

You can also contact DiCello Levitt partner Brian O’Mara by calling (888) 287-9005 or at [email protected]. 

The deadline to apply to the Court to serve as lead plaintiff in the Actinium class action lawsuit is May 27, 2025.