Positive FDA Feedback for Proposed In Vitro Bridging Strategy for Alcohol Use Disorder Treatment, AD04

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Adial Pharmaceuticals today announced a positive response from the US Food and Drug Administration (FDA) regarding its proposed in vitro bridging strategy for the phase 3 formulation of AD04, an investigational selective serotonin-3 receptor (5-HT3) antagonist. This will fulfill the bridging requirement for the 505(b)(2) regulatory registration pathway for approval.¹

“This milestone is an essential step forward in our efforts to advance AD04 into phase 3 clinical development and, ultimately, toward regulatory approval,” said Cary Claiborne, CEO of Adial Pharmaceuticals. “The FDA’s confirmation of our proposed in vitro bridging strategy brings us closer to achieving our goal of delivering a new treatment option for patients struggling with addiction.”

On November 19, 2024, Adial sought guidance from the FDA on the alignment of its AD04 formulation strategy and bridging approach, a crucial step in ensuring compliance with the 505(b)(2) regulatory approval pathway following the completion of the pivotal AD04-103 study. Additionally, Adial sought to secure confirmation from the FDA that the proposed data package would meet the necessary bridging requirements and allow for AD04 to progress into phase 3 clinical trials.

The FDA agreed with Adial’s proposed 505(b)(2) bridging strategy of leveraging the results from the relative bioavailability food-effect study, AD04-103, along with in vitro dissolution data demonstrating equivalence between the comparison product and the planned commercial formulation of AD04. Even though the final determination will depend on a comprehensive review of the complete New Drug Application (NDA), the FDA’s agreement represents a significant regulatory milestone for Adial.

After securing this regulatory confirmation, Adial will proceed with manufacturing clinical supply materials in preparation for the upcoming phase 2 clinical program in 2025. In a press release, Adial shared that it “remains committed to executing its development plan and working closely with regulatory authorities to bring AD04 to market as a potential breakthrough therapy for addiction.”¹

This news follows the recent update regarding AD04’s patent: On February 11, 2025, the United States Patent and Trademark Office issued patent number 12,221,654 for Adial Pharmaceuticals’ identification of patients with specific genetic markers linked to substance use disorders and treatment with AD04.² The AD04 treatment involves first detecting the TT genotype of rs1042173 in the serotonin transporter gene (SLC6A4) and then administering AD04 for individuals with opioid use disorder, alcohol use disorder, and other related conditions.

“This patent is an important milestone for Adial Pharmaceuticals as we continue our mission to create innovative, personalized treatments for addiction. Our research not only helps us understand the genetic underpinnings of addiction but also positions us to deliver solutions that are more effective and tailored to individual patients. We believe AD04 has significant potential to treat opioid use disorder and other drug dependencies in addition to our initial indication of alcohol use disorder. By combining genetic diagnostics with precision medicine, we aim to improve outcomes for patients who may not respond to traditional treatments,” said Clairborne.²

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References

1. Adial Pharmaceuticals receives positive response from FDA meeting regarding proposed in vitro bridging strategy for AD04. News release. February 25, 2025. https://www.adial.com/adial-pharmaceuticals-receives-positive-response-from-fda-meeting-regarding-proposed-in-vitro-bridging-strategy-for-ad04/

2. Kuntz L. Patent issued for methods of identifying patients with substance use-associated genetic markers, treatment with AD04. Psychiatric Times. February 12, 2025. https://www.psychiatrictimes.com/view/patent-issued-for-methods-of-identifying-patients-with-substance-use-associated-genetic-markers-treatment-with-ad04