Lantheus Holdings, Inc. (LNTH) Securities Class Action Lawsuit Update [October 9, 2025]

Introduction to Lantheus Holdings, Inc. (LNTH) Securities Class Action Lawsuit

A securities fraud class action has been filed against Lantheus Holdings, Inc. (NASDAQ: LNTH) covering investors who purchased the Company's securities between February 26, 2025 and August 5, 2025, inclusive. Investors allege the Company misrepresented its understanding of pricing and competition for Pylarify and its ability to maintain market leadership, a pricing premium, and 2025 growth consistent with guidance. According to the complaint, Lantheus assured the market that Pylarify would grow and retain its premium despite competitive pressures, while concealing adverse facts about its true competitive position. The truth allegedly emerged through disclosures on May 7, 2025 and August 6, 2025 revealing competitive disruption, aggressive competitor discounting, and reduced growth expectations. As a result, investors claim they purchased shares at artificially inflated prices and suffered damages when the stock declined following these revelations.

Lantheus Holdings, Inc. (LNTH) Securities Lawsuit Case Details

Case Name: Margolis v. Lantheus Holdings, Inc., et al.
Case No.: 1:25-cv-07491
Jurisdiction: U.S. District Court, Southern District of New York
Filed on: September 9, 2025

Lantheus Holdings, Inc. (LNTH) Company Profile

Lantheus develops, manufactures, sells, and distributes diagnostic and therapeutic products across Radiopharmaceutical Oncology, Precision Diagnostics, and Strategic Partnerships and Other Revenue. Its key radiopharmaceutical product is Pylarify, a PET imaging agent used to assist in diagnosing and treating prostate cancer.

Lantheus Holdings, Inc. (LNTH) Securities Lawsuit Class Period

February 26, 2025–August 5, 2025, inclusive

Investor eligibility: all investors who purchased or otherwise acquired Lantheus securities during the Class Period may be eligible to join the Lantheus Holdings, Inc. (LNTH) class action lawsuit.

Allegations in the Lantheus Holdings, Inc. (LNTH) Securities Class Action Lawsuit

The lawsuit targets Lantheus Holdings, Inc. and executives Paul M. Blanchfield (President), Brian A. Markison (Chief Executive Officer and Director), Robert J. Marshall (Chief Financial Officer and Treasurer), and Amanda M. Morgan (Chief Commercial Officer). According to the complaint, defendants told investors they understood Pylarify's pricing and competitive environment and could maintain market leadership, a pricing premium, and continued growth in 2025, while concealing adverse competitive realities.

On February 26, 2025, during an earnings call, President Paul M. Blanchfield stated that with over $1 billion in sales, Pylarify remained the clear number one utilized PSMA PET imaging agent, and he expressed confidence in growing both volume and net sales in 2025 while maintaining market leadership and a relative price premium despite competitive pressures. That same day, CFO Robert J. Marshall guided full-year 2025 net revenue to $1.545–$1.61 billion—an increase of 1% to 5% over 2024—and said Pylarify was expected to grow low to mid-single digits on a net basis. Also on February 26, Chief Commercial Officer Amanda M. Morgan said the Company expected to continue capitalizing on Pylarify's clinical and commercial differentiation to support its clear market leadership and pricing premium even given current competitive dynamics.

Meanwhile, the complaint alleges that Lantheus was not equipped to properly assess Pylarify's pricing and competitive dynamics. It further alleges the Company failed to disclose that an early 2025 price increase—implemented after price erosion the prior year—created an opening for competitive pricing to flourish. According to investors, these undisclosed dynamics put Pylarify's price point, revenue, and overall growth potential at risk during the Class Period.

The Truth Emerges

On May 7, 2025, Lantheus issued a press release and held an earnings call acknowledging that Pylarify sales had decreased year over year due to what management called "temporal competitive disruption" among smaller non-contracted sites. The Company reduced its full-year Pylarify outlook from low-to-mid single-digit growth to flat to low single-digit percent growth, contradicting prior confidence about sustaining premium pricing and leadership amid competition.

Then on August 6, 2025, Lantheus issued a press release and held an earnings call where it was disclosed that Pylarify sales fell 8.3% year over year and explained that aggressive discounting by an F-18 competitor, together with MUC-based reimbursement, led some economically sensitive customers to reassess their choice of PSMA agents. Management also noted the Company walked away from volumes at certain accounts. These admissions directly undercut the February 26 assurances about maintaining a pricing premium and growth and cast earlier "temporal" disruption as part of a deeper competitive problem.

Market Reaction

The market responded swiftly to the May 7, 2025 disclosure. From a prior close of $104.84 per share on May 6, Lantheus' stock fell $24.35, or 23.2%, to close at $80.49 on May 7, 2025, as investors absorbed the competitive disruption and reduced growth outlook.

The August 6, 2025 update prompted a second sharp decline. From a closing price of $72.83 on August 5, Lantheus' shares fell $20.96, or 28.8%, to close at $51.87 on August 6, 2025, following management's disclosure of an 8.3% year-over-year sales drop in Pylarify and aggressive competitor discounting.

Next Steps

• Submissions for lead plaintiff are due November 10, 2025. 
• The Court will issue its order for lead plaintiff and counsel in the weeks after submissions are due.
• The Court will then consider motion for class certification.
• The Court will later consider a Motion to Dismiss.

To learn if you are eligible for recovery under the LNTH securities class action lawsuit, visit the case submission page here.

Disclaimer: This shareholder alert is for informational purposes only and does not constitute legal advice. Consult a qualified attorney for personalized guidance. No specific outcomes are guaranteed.