The U.S. Food and Drug Administration issued a decision letter on January 8 2026 rejecting Vanda Pharmaceuticals’ supplemental New Drug Application for HETLIOZ® (tasimelteon) in the jet‑lag disorder indication. The letter states that the application cannot be approved in its current form.
The FDA acknowledged that Vanda’s controlled clinical trials demonstrated positive efficacy, but concluded that the data do not provide substantial evidence of effectiveness for jet‑lag. The agency cited the use of phase‑advance protocols—shifting bedtime by 5 hours and 8 hours—as insufficiently analogous to real‑world jet travel, which involves additional factors such as reduced oxygen pressure, physical constraints, noise, and lighting changes. Vanda’s same‑day response disputed the FDA’s interpretation, arguing that phase‑advance models are widely accepted in circadian rhythm research and that the submitted dataset meets the statutory standard for substantial evidence.
The decision follows a series of legal and regulatory milestones. In January 2024 a federal judge ordered the FDA to resolve the sNDA or grant a hearing, and in August 2025 the court overturned the FDA’s earlier refusal, prompting the agency to commit to an expedited re‑review under a collaborative framework agreement signed in October 2025. The current rejection marks a new setback in a protracted regulatory battle that began with the FDA’s initial refusal in 2019.
Vanda’s financial performance in 2024 reflected the impact of generic competition on HETLIOZ®. Net product sales fell 23 % to $76.7 million from $100.2 million in 2023, while the company posted a net loss of $18.9 million for the year, compared with a $2.5 million net income in 2023. Other products—Fanapt® and Ponvory®—provided modest revenue growth, but the jet‑lag indication had been viewed as a key growth driver for the company’s portfolio.
The rejection limits Vanda’s ability to expand HETLIOZ® into the jet‑lag market, which could have added a significant revenue stream given the estimated global market size of several billion dollars. The company’s pipeline, including Fanapt®, Ponvory®, and the upcoming Bysanti™ NDA, remains a source of potential upside, but the loss of the jet‑lag indication underscores the challenges of translating circadian research into regulatory approval and highlights the importance of robust clinical evidence that mirrors real‑world conditions.
Investors reacted negatively to the FDA decision, reflecting concerns about the company’s growth prospects and the broader impact of regulatory uncertainty on its drug portfolio.
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