ImmunityBio Shares Plummet Following FDA Rebuke Over Marketing Claims

The biotechnology firm ImmunityBio finds itself caught between significant operational progress and mounting regulatory scrutiny. A recent official warning from the U.S. Food and Drug Administration (FDA) triggered a sharp 21% single-day decline in the company’s stock, erasing nearly $2 billion in market capitalization.

The regulatory action centers on promotional materials for the bladder cancer therapy Anktiva. The FDA has determined that a television advertisement and a podcast featuring Chairman and CEO Dr. Patrick Soon-Shiong were misleading. According to the agency, these materials overstated the drug’s efficacy and promoted unapproved methods of administration, such as subcutaneous injections, while omitting critical safety information. The situation is compounded by the FDA’s assertion that ImmunityBio failed to address two prior warnings issued in 2025 and 2026.

Legal Repercussions Mount for Management

The fallout from the FDA’s reprimand is expanding into the legal arena. The Rosen Law Firm has filed a securities class action lawsuit on behalf of investors who purchased ImmunityBio stock between mid-January and the end of March 2026. The suit alleges the company’s leadership artificially inflated perceptions of Anktiva’s capabilities, thereby creating false market expectations. A lead plaintiff for the case is to be appointed by a California court before the close of May 2026.

Concurrently, ImmunityBio faces a pressing 15-day deadline to submit a comprehensive corrective action plan to the FDA, detailing how it will address the cited violations in its promotional campaigns.

Should investors sell immediately? Or is it worth buying ImmunityBio?

Strong Commercial Performance Provides a Counter-Narrative

Amidst these legal and regulatory challenges, the company’s underlying business tells a different story. ImmunityBio reported 2025 net sales for Anktiva of $113 million, representing a staggering increase of approximately 700% year-over-year. The clinical development program also continues to advance.

Recent milestones include the adoption of the therapy into the National Comprehensive Cancer Network’s treatment guidelines for specific bladder cancer patients. Furthermore, the company has completed patient enrollment for its pivotal QUILT-2.005 clinical trial. Interim results from this study have indicated an improved duration of response for participants.

A Stock Caught Between Two Realities

ImmunityBio’s equity now trades at the intersection of these divergent narratives. The existing drug approvals and a planned regulatory submission for the fourth quarter of 2026 underpin the fundamental business case. However, the weight of regulatory risk and ongoing litigation continues to pressure the stock’s valuation.

In the immediate term, investor attention is fixed on the company’s response to the FDA’s 15-day ultimatum. Management’s ability to present a convincing resolution to the marketing dispute will be a critical test.