Legal Battle Erupts Over Prostate Cancer Drug Marketing Claims

Bayer files lawsuit against Johnson & Johnson, alleging misleading promotional claims for Erleada that target its rival drug Nubeqa. The case centers on the use of real-world data in marketing.

A significant legal dispute has emerged within the pharmaceutical industry, pitting two major players against each other. Bayer AG has initiated legal proceedings against Johnson & Johnson and its subsidiary, Janssen Biotech, alleging misleading promotional activities. The lawsuit, filed in the U.S. District Court for the Southern District of New York, centers on a marketing campaign for J&J's prostate cancer treatment, Erleada, which Bayer contends directly targets its competing drug, Nubeqa.

Questioning the Validity of Comparative Claims

The conflict stems from a promotional initiative launched by Johnson & Johnson in February. In this campaign, the U.S. healthcare giant presented findings from a retrospective analysis, claiming its drug Erleada demonstrated a 51% reduction in mortality risk when compared to Bayer's Nubeqa. Bayer has forcefully rejected this characterization, labeling the underlying science as flawed.

Bayer's legal filing challenges whether retrospective observational studies provide sufficient grounds for such broad superiority claims against a competitor. The company argues that J&J's approach disregards established regulatory standards for head-to-head clinical trials. The analysis in question compared data from 1,460 patients on Erleada with information from just 287 individuals using Nubeqa. Furthermore, Bayer's complaint highlights a critical data distortion: during the studied period, Nubeqa was primarily used outside its official label indications, a factor Bayer states renders any direct comparison invalid.

High Stakes in a Lucrative Oncology Market

This litigation underscores the intense rivalry in a highly profitable oncology segment. Both medications are approved for treating metastatic, hormone-sensitive prostate cancer. For Bayer, Nubeqa represents a pivotal growth driver for its pharmaceuticals division, having generated global sales of approximately €1.63 billion in the first nine months of 2025. Johnson & Johnson, however, continues to lead the market with Erleada, which reported total annual sales of $3.57 billion for the full year 2025.

In its legal action, Bayer is seeking a permanent injunction to halt the advertising campaign. The company has also requested a court-mandated corrective statement and is pursuing financial damages. These damages would include the disgorgement of what it deems unlawfully obtained profits, as well as coverage for its associated legal costs. Johnson & Johnson has defended the methodology of its analysis, stating it complies with regulatory frameworks for real-world data.

The outcome of this case will hinge on the court's determination of whether real-world evidence can legitimately support aggressive marketing comparisons, or if Bayer is entitled to compensation for potential market share erosion. The proceedings will be closely watched for their implications on pharmaceutical marketing practices.