The DC-based biopharma disputed the FDA’s conclusions regarding the data provided in its supplemental application for Hetlioz and promised to keep pushing for an approval.
The FDA has rejected Vanda Pharmaceuticals’ Hetlioz for jet lag due to disagreements over how the drug was tested, sending the company’s shares tumbling yet again after a regulatory mishap.
Vanda is seeking a supplemental approval for Hetlioz, which is already authorized for several different sleep disorders. While the FDA concluded in its Complete Response Letter (CRL) that Vanda had shown “positive efficacy” in clinical trials for jet lag, the agency also determined that the data did not show that Hetlioz effectively treated jet lag syndrome, according to company’s Thursday announcement.
Vanda modeled the effects of jet lag using phase advance protocols in Phase II and III trials completed in 2017 and 2018 by shifting patient bedtimes by five and eight hours. The FDA did not view this method as “sufficiently analogous” to real-life jet travel, which also involves reduced oxygen pressure, physical confinement, noise and lighting changes, Vanda said.
“Vanda respectfully disagrees with this interpretation,” the company wrote in its statement. “Phase advance models are widely accepted in circadian rhythm research as valid and reliable surrogates for simulating the core circadian misalignment underlying eastward jet lag.”
The company continued: “These models reproducibly induce the essential features of jet lag without the confounders of variable travel conditions which are unrelated to jet lag.”
Shares of Vanda fell about 11% to $7.60 apiece in Thursday trading.
The rejection is the latest chapter in Vanda’s saga of headbutting with the FDA. The company has been fighting to market Hetlioz for jet lag since 2019, when the FDA first rejected the drug for the disorder. Vanda unsuccessfully attempted to secure hearings with the agency on the application, hoping to resolve the issues, eventually suing the FDA. In January 2024, a judge ruled in favor of Vanda, ordering the FDA to resolve the supplemental new drug application (sNDA) or grant Vanda a hearing.
In lieu of a hearing, the FDA handed the company a rejection. Vanda appealed and in August 2025, won again, with a judge overturning the FDA’s rejection. After that ruling, the FDA and Vanda in October 2025 entered into a “collaborative framework agreement,” according to Vanda’s most recent statement, where the agency agreed to an expedited re-review of the sNDA by January 7, 2026.
Vanda does not appear to see this as the end of the road for Hetlioz and jet lag. The company’s statement said that it “appreciates” working with the FDA on the application, and that it will continue pursuing “all appropriate avenues” to get Hetlioz approved for jet lag.
Other examples of Vanda’s dealings with the FDA include suing the agency in April 2025 over restrictions on information the company could provide to doctors on off-label use of Hetlioz for jet lag. The same month, the company also complained about “FDA bureaucrats” who rejected the company’s gastroparesis drug candidate tradipitant.
Last week, the FDA approved Vanda’s motion sickness drug Nereus, ending a 40-year drought of new treatments in the space.
