Pharma, dietary supplement interests collide in court over NMN

A clinical-stage pharmaceutical firm wants to intervene in a lawsuit regarding the legality of an anti-aging ingredient marketed in dietary supplement products, but the trade association that filed the complaint against the U.S. Food and Drug Administration opposes the request. 

Metro International Biotech LLC told a federal court on Nov. 27 that it has invested years and millions of dollars developing NMN (nicotinamide mononucleotide) as a drug and that it has the right to intervene in the lawsuit. 

FDA has concluded NMN cannot be lawfully marketed in supplements under a clause in the Dietary Supplement Health and Education Act of 1994 (DSHEA). It’s a position that the Natural Products Association (NPA) contests and is seeking to overturn in its lawsuit pending in the U.S. District Court for the District of Columbia. 

A clause in the law bars an ingredient from being marketed in a dietary supplement if it was first approved as a drug or first authorized for investigation as a new drug and the subject of “substantial clinical investigations” that have been instituted and made public. 

“NPA has sued challenging FDA’s reliance on the DSHEA preclusion clause to bar the marketing and sale of NMN as a supplement. If NPA wins, FDA will be unable to take any action inconsistent with classifying NMN as a supplement,” lawyers for Metro wrote in court papers supporting their motion to intervene. “Such a result would remove the benefit to Metro and overturn the regulatory landscape on which Metro has built its drug development program. Consequently, Metro has standing to intervene.” 

Related:Judge pauses court case against FDA over NMN supplements

In October, U.S. District Judge Paul L. Friedman ordered that all proceedings in the lawsuit are stayed until FDA answers a citizen petition filed by NPA. He deferred all deadlines in the case except that he required NPA to submit to the court a response to Metro's motion to intervene in the lawsuit.

According to a joint motion filed in court by NPA and the government, while the lawsuit contains some arguments beyond those asserted in the citizen petition, “FDA will consider them as part of its evaluation of the citizen petition.” That is so long as “NPA promptly supplements its citizen petition to include those additional arguments.” 

NPA has objected to Metro’s motion to intervene, arguing the pharma company can protect its interests by commenting on the amended citizen petition.  

Metro in November 2023 filed comments with FDA, in response to NPA’s original petition. The company agreed with FDA that NMN is properly barred from being marketed as a dietary supplement.  

Related:FDA telegraphs enforcement strategy against NMN supplements amid NPA lawsuit

“Metro’s motion to intervene should be denied because the fate of this case is now entirely dependent on the resolution of NPA’s amended citizen’s petition, and so permitting intervention in a case where the underlying facts will go stale after the amended citizen’s petition will only serve to complicate proceedings,” attorneys for NPA wrote in court papers.  

NPA’s lawyers requested that the court deny Metro’s motion to intervene, or in the alternative, deny the motion “without prejudice,” which would allow Metro to renew its motion after FDA answers NPA’s amended citizen petition.  

FDA has indicated it plans to respond to the petition by no later than July 31, 2025. The petition was filed in 2023 by NPA and the Alliance for Natural Health. 

Meantime, FDA has signaled it does not intend to prioritize enforcement against NMN products marketed as supplements while it considers the petition — absent any emerging safety issues. 

According to Metro, FDA cannot sufficiently represent its interests in the NPA lawsuit.

Since the company filed its motion to intervene, “the government has demonstrated its inability to protect Metro’s interests by promising not to prioritize enforcement during the pendency of the stay — thereby allowing NMN to be sold as a supplement notwithstanding FDA’s determination that DSHEA’s preclusion clause makes it unlawful to do so,” Metro stated in its court filing.

The law firm Arnall Golden Gregory LLP (AGG) represents NPA. Metro is represented by Arnold & Porter Kaye Scholer LLP.