FDA again rejects Vanda’s Hetlioz for jet lag after yearslong dispute and ‘long‑shot’ re‑review

The FDA’s Center for Drug Evaluation and Research sent Vanda a decision letter stating that the supplemental New Drug Application (sNDA) for Hetlioz (tasimelteon) for jet lag disorder cannot be approved in its current form.3 2

The FDA acknowledged positive efficacy signals from Vanda’s controlled clinical trials but concluded the data do not provide substantial evidence of effectiveness for jet lag disorder.3 2

The agency’s key objection is that Vanda’s controlled phase‑advance protocols—5‑hour and 8‑hour bedtime shifts used to simulate eastward travel—are not sufficiently analogous to actual jet travel, which also includes reduced oxygen pressure, physical constraints, noise, and lighting changes.3 2 1

This is at least the second FDA rejection of Hetlioz for a jet lag indication, following an earlier refusal to approve a label expansion for the drug.1 6 4

Vanda had previously sued the FDA over its handling of the application; in January 2024 a judge ordered the agency to resolve the sNDA or grant a hearing, and in August 2025 the D.C. Circuit set aside a prior FDA refusal, criticizing the FDA’s review as “cursory.”1 3

Following the August 2025 appeals court ruling, Vanda and FDA entered an October 2025 “collaborative framework agreement,” under which FDA agreed to an expedited re‑review of the sNDA by January 7, 2026, including consideration of narrowed, sleep‑focused indications.1 3

The latest decision letter stems from that expedited re‑review and effectively represents the outcome of what observers considered a “long‑shot” second look after Vanda’s court win.1 2

Hetlioz is already approved in the U.S. for other sleep‑related indications (such as non‑24‑hour sleep‑wake disorder and nighttime sleep disturbances in Smith‑Magenis syndrome), and Vanda emphasized its established safety profile from more than a decade of use in those chronic indications.1 3 2

Vanda strongly disputes FDA’s interpretation, arguing that phase‑advance models are widely accepted in circadian rhythm research as valid surrogates for the core circadian misalignment driving eastward jet lag, and that its data—including simulated and actual transatlantic travel studies—show meaningful benefits on sleep duration, sleep latency, and next‑day alertness.3 5

Despite the new setback, Vanda says it remains committed to working constructively with FDA and will pursue all appropriate avenues to advance approval of Hetlioz for jet lag disorder.3 1 4

News of the latest rejection led to a sharp decline in Vanda’s share price, with premarket losses reported around 10–12% after the announcement.4 5 9