FDA Approves Sanofi/Regeneron's Dupixent for Chronic Hives After Rejection

In a significant development for patients with chronic spontaneous urticaria (CSU), the U.S. Food and Drug Administration (FDA) has approved a new use for Dupixent, a biologic drug developed by Sanofi and Regeneron. This approval marks the first time in more than a decade that a new targeted therapy has been sanctioned for this condition. Dupixent is now available for patients aged 12 and older who continue to experience symptoms despite taking antihistamines.

The journey to this approval was not straightforward. In October 2023, the FDA initially rejected Dupixent for the treatment of CSU due to concerns over insufficient efficacy data. To counter this, Sanofi and Regeneron submitted additional data from three studies under the Phase III LIBERTY-CUPID program. These studies were designed to demonstrate the drug's effectiveness in treating CSU.

The first two studies, Study A and Study B, were initially part of Dupixent’s approval application. Study A, conducted in July 2021, showed that Dupixent significantly reduced itching and urticaria activity scores, roughly halving them when compared to antihistamines. However, Study B, which was reported in February 2022, provided less encouraging results. It showed only modest improvement over antihistamines for patients unresponsive to Novartis and Roche’s Xolair, leading to its termination due to lack of efficacy.

Sanofi and Regeneron persisted by conducting Study C, also under the LIBERTY-CUPID program. The results, released in September 2024, reinforced findings from Study A, showing that Dupixent reduced itch and urticaria activity by nearly 50%. The safety profile of Dupixent in CSU was consistent with its established use in other dermatological conditions.

This approval marks Dupixent's seventh endorsement for diseases driven by type 2 inflammation, which involves similar inflammatory mechanisms. The drug operates by inhibiting the receptors for IL-4 and IL-13 cytokines, thereby disrupting inflammation-related signaling pathways. This mechanism is effective in suppressing inflammation underlying several immune-related conditions, including asthma and rhinosinusitis.

Since its initial approval in 2017 for atopic dermatitis, Dupixent has expanded its indications. In September 2024, it became the first biologic approved for chronic obstructive pulmonary disease. The drug has been a commercial success for Sanofi and Regeneron, with sales rising 22% last year to reach $14.15 billion globally. With its new approval for CSU, Dupixent's revenue is expected to increase further. Additionally, Sanofi and Regeneron have submitted a supplemental Biologics License Application (sBLA) for bullous pemphigoid, anticipating a decision later this year.

Despite its commercial triumphs, Dupixent has also been at the center of a legal dispute between Sanofi and Regeneron. In November 2024, Regeneron filed a lawsuit against its French partner, alleging it was denied access to critical sales information. This lawsuit was publicly disclosed in Regeneron’s annual report in February.

Overall, the FDA's approval of Dupixent for CSU represents a significant advancement for patients with limited treatment options and underscores the ongoing developments and complexities within the pharmaceutical industry.