Vanda Challenges FDA Rejection of Gastroparesis Drug, Criticizes Delay

Vanda Pharmaceuticals announced on Thursday that the FDA has declined to approve its application for tradipitant, an investigational NK-1R antagonist aimed at treating gastroparesis. The company alleges that this decision came after significant delays of over 185 days, exceeding the Federal Drug and Cosmetic Act's (FDCA) stipulated review period. According to Vanda, the FDA's Complete Response Letter (CRL) was vague and failed to properly consider the evidence provided by the company. The FDA has requested additional studies, which Vanda claims are inconsistent with the recommendations from key experts.

Jefferies analyst Andrew Tsai noted that the rejection was expected, citing a failed Phase III study and an unresolved request from the FDA for further animal and long-term safety analyses. Vanda anticipated this outcome, having mentioned in its second-quarter business report that the FDA had flagged "deficiencies" in its application.

Despite the setback, Vanda maintains confidence in tradipitant, asserting that their data package demonstrates substantial evidence of the drug’s efficacy and a favorable benefit-risk profile for treating gastroparesis. The company plans to continue seeking approval for tradipitant and will maintain its expanded access program for gastroparesis patients.

In addition to gastroparesis, Vanda is preparing a separate application for tradipitant to prevent vomiting associated with motion sickness, with plans to file later this year.

Reacting to the FDA's decision, Vanda criticized the agency for its delayed response, which they claim violates the FDCA's 180-day review period rule. The company also expressed frustration with the FDA's failure to seek external guidance on the application, despite Vanda’s repeated requests for an advisory committee review.

Tradipitant works by antagonizing neurokinin (NK)-1 receptors, which are prevalent in the gastrointestinal tract and brain regions involved in the vomit reflex. This mechanism helps alleviate nausea and vomiting symptoms commonly associated with gastroparesis.

Vanda supported its regulatory submission with data from various clinical efficacy studies, a 12-week open-label study, findings from its expanded access program, and non-animal preclinical studies. The company noted that several patients currently on tradipitant have filed a citizen petition urging the FDA to approve the drug for gastroparesis.

This rejection comes shortly after Vanda filed a lawsuit against the FDA, arguing that the agency's drug approval process is unconstitutional. The complaint, filed earlier this month, underscores Vanda's continued disputes with the FDA, including a previous instance in February 2024 when the agency rejected the expansion of Vanda’s Hetlioz (tasimelteon) into treating insomnia.

The company's recent interactions with the FDA highlight ongoing tensions and underscore the challenges that can arise in the drug approval process, particularly when there are disagreements over the sufficiency and interpretation of clinical data.