ImmunityBio Plummets 22.4% After FDA Issues Third Misleading Ad Warning

IBRX Stock Collapses 22.4% After FDA Cites 'False and Misleading' Ads

ImmunityBio (NASDAQ: IBRX) shares erased recent gains, falling 22.4% on March 24 after the U.S. Food & Drug Administration (FDA) issued a warning letter over promotional materials. The drop occurred just one day after the stock rallied on news of Anktiva's approval in Macau for treating certain bladder cancers. The FDA's letter identified a television advertisement and comments made by Executive Chairman Dr. Patrick Soon-Shiong on a recent podcast as "false and misleading." Regulators stated these promotions made broad efficacy claims for the cancer treatment Anktiva that have not been substantiated by clinical trials.

FDA Highlights 'Concerning Pattern' With Third Warning

The FDA's action is not an isolated incident but part of what the agency called a "concerning pattern." This marks the third time regulators have formally addressed misleading promotions with the company. The FDA's Office of Prescription Drug Promotion (OPDP) had previously sent letters regarding similar issues to ImmunityBio's subsidiary, Altor BioScience, in September 2025 and January 2026. The OPDP expressed concern that ImmunityBio continues to promote Anktiva in a misleading manner, specifically by implying the drug is a cancer vaccine when it is approved strictly as a treatment. This history of repeated warnings suggests a systemic issue within the company's public communications and compliance.

Investor Scrutiny Mounts as Law Firm Launches Probe

The recurring regulatory issues risk damaging ImmunityBio's reputation and could undermine investor confidence in its pipeline of 12 other clinical trials. While the misleading ads may not have directly driven revenue, the repeated FDA interventions create significant legal and financial overhang. In response to the stock's sharp decline and the allegations of misleading statements, Rosen Law Firm announced on March 24 that it has launched an investigation into potential securities claims on behalf of IBRX shareholders. This legal scrutiny adds another layer of risk for investors, compounding the volatility created by the regulatory actions.