ImmunityBio (IBRX) is lower in Thursday trading (April 16, 2026) as the market continues to price in fallout from the FDA’s Office of Prescription Drug Promotion warning letter dated March 13, 2026, which challenged promotional communications around ANKTIVA. The decline is being reinforced by renewed legal overhang headlines after multiple investor alerts circulated around April 15, 2026, highlighting a May 26, 2026 lead-plaintiff motion deadline in a securities class action tied to the same FDA-promotion controversy.

The FDA’s posted warning letter focuses on claims that could imply broader efficacy beyond ANKTIVA’s approved labeling and on risk-presentation concerns in consumer-facing communications. ImmunityBio has publicly said it submitted a comprehensive response to the OPDP and took corrective steps, including removing the cited podcast content and stating the cited television advertisement was never aired—yet investors are treating the situation as an ongoing uncertainty until FDA follow-up is clearer.

The April 15, 2026 investor alerts keep the story in front of traders by framing the FDA communication as the core event behind alleged disclosure and promotional-control failures. Even if these notices don’t change the underlying facts, the repeated reminders can pressure sentiment by highlighting potential litigation expense, management distraction, and the risk of additional disclosures as the case progresses toward the late-May procedural deadline.