On Aug. 18, 2025, Vanda Pharmaceuticals announced that it secured a landmark victory over the U.S. Food and Drug Administration (FDA) in its longstanding dispute with the agency regarding the approvability of HETLIOZ^® (tasimelteon) to treat jet lag disorder (Vanda Pharmaceuticals Inc. v. FDA, case no. 24-1049).

Vanda submitted its supplemental New Drug Application (sNDA) in October 2018 to market HETLIOZ^® to treat jet lag disorder. After the FDA substantially delayed resolving Vanda’s request for a hearing with respect to this application, a federal district court found that the FDA “violated” the requirements of the Food, Drug, and Cosmetic Act, and the court ordered the FDA to finally resolve Vanda’s sNDA or commence a hearing (Vanda Pharmaceuticals Inc. v. FDA, No. 22-cv-2775-CJN).

The FDA did not commence a hearing. It instead granted summary judgment to itself and issued an order refusing to approve the sNDA. The FDA took the position that it could essentially disregard the voluminous factual evidence Vanda had presented to it. Vanda thus filed a petition for review with the U.S. Court of Appeals for the D.C. Circuit (the Court).

In a sweeping win for Vanda, the Court set aside the FDA’s action. The Court explained that Vanda provided expert views that were “specific, reasoned, and rooted in evidence” and that the FDA’s “treatment of Vanda’s evidence is cursory.” In particular, the Court stated that Vanda “clearly offered meaningful evidence of tasimelteon’s efficacy in improving sleep disturbance” and, further, that each of its trials “showed statistically significant improvement on the primary endpoint measured.”

This decision significantly alters the relationship between the FDA and the parties it regulates. The Court’s holding establishes that the FDA must meaningfully engage with the evidence presented by drug innovators, and the FDA may not shield its decisions via a plea for deference. The Court has remanded the case back to the FDA, where Vanda anticipates the FDA will either approve the sNDA or Vanda will receive a hearing.