ImmunityBio (IBRX) Shares Plunge 21% Following FDA Warning Letter on Misleading Cancer Drug Marketing

Key Takeaways

• Federal regulators sent ImmunityBio a formal warning letter regarding a television advertisement and podcast episode containing misleading statements about ANKTIVA
• Marketing content inaccurately implied the drug could address all forms of cancer, despite approval limited exclusively to a narrow bladder cancer indication used with BCG therapy
• Both CEO Richard Adcock and Executive Chairman Dr. Patrick Soon-Shiong were explicitly named in the regulatory violation notice
• This represents the company’s third regulatory notice regarding promotional compliance, with prior communications sent in September 2025 and January 2026
• ImmunityBio must submit a comprehensive remediation strategy within 15 business days or risk enforcement proceedings

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Shares of ImmunityBio experienced a significant decline on Tuesday following regulatory action by the FDA, which identified violations in a television commercial and podcast episode that contained unsubstantiated claims regarding the scope of ANKTIVA’s therapeutic applications. This represents the third instance of promotional compliance issues for the biotechnology firm.

The warning letter originated from the FDA’s Office of Prescription Drug Promotion after reviewing a TV spot and a podcast episode entitled “Is the FDA BLOCKING Life Saving Cancer Treatments?” According to regulators, both pieces of content violated federal pharmaceutical marketing statutes.

The regulatory concern centered on misrepresentation of the drug’s approved indication. ANKTIVA received authorization exclusively for treating adult patients diagnosed with BCG-unresponsive non-muscle invasive bladder cancer featuring carcinoma in situ, either with or without papillary tumors, delivered via direct bladder administration in combination with BCG therapy.

ImmunityBio, Inc., IBRX

The challenged marketing content significantly exceeded these parameters. The materials implied ANKTIVA possessed capabilities to “treat all cancers,” provide cancer prevention for individuals with radiation exposure, and function as a standalone single-injection therapy. Federal regulators emphasized that none of these assertions have clinical evidence backing or regulatory approval.

Both company leadership figures—CEO Richard Adcock and Executive Chairman Dr. Patrick Soon-Shiong—made appearances in the questioned materials and were specifically identified in the regulatory correspondence.

According to the FDA, these promotional activities constituted misbranding of ANKTIVA and rendered its distribution a breach of the Federal Food, Drug, and Cosmetic Act.

Pattern of Regulatory Concerns

This enforcement action isn’t ImmunityBio’s initial encounter with promotional compliance issues. ImmunityBio previously received untitled letters from the FDA in September 2025 and January 2026, directed to its subsidiary Altor BioScience, addressing comparable marketing violations.

Tuesday’s correspondence represents the third regulatory communication—and carries substantially greater weight. Warning letters from the FDA hold more serious regulatory implications compared to untitled letters, indicating heightened agency concerns about ongoing violations.

Regulators additionally cited the company for inadequate presentation of risk information throughout the materials and for excluding critical details about the drug’s precise approved medical use.

The podcast episode also violated a separate requirement: it wasn’t submitted to FDA review at the time of its original release, representing an additional compliance failure.

Investor Response

IBRX shares declined approximately 15% to 21% during Tuesday’s trading session, with certain market observers documenting the decrease reaching the upper end of that range during morning hours.

ImmunityBio faces a 15-business-day deadline to provide federal regulators with a written response detailing its corrective action plan addressing the identified violations.

The biotechnology company must also develop and distribute corrective communications specifically designed to reach audiences exposed to the misleading promotional content.

The FDA explicitly cautioned that inadequate response or insufficient corrective measures could trigger formal legal enforcement actions.

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