FDA knocks down Enzyvant candidate on manufacturing concerns after plant inspection

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Enzyvant's candidate was part of the FDA's regenerative medicine program. (FDA)

Privately held biotech Enzyvant was hoping its first shot at an FDA approval with a rare immunodeficiency disease candidate would come up in its favor. But the FDA has dashed those hopes, citing manufacturing concerns in a response letter—at least, for now.

Enzyvant said it received an FDA complete response letter pointing to manufacturing control issues after an inspection for RVT-802, the company's late-stage candidate for congenital athymia, a rare immunodeficiency disorder affecting infants, Reuters reported. 

Many of the issues cited in the letter were known by the drugmaker and were not considered prerequisites for approval, CEO Rachelle Jacques told the news service.

“Many of these are topics that we are very aware of and we anticipated those to be post-marketing commitments, not approval requirements,” she said.

RVT-802 is a drug tagged under the FDA's Regenerative Medicine Advanced Therapy designation reserved for conditions lacking approved treatments. Enzyvant hoped the treatment would become the first to treat congenital athymia, a disorder affecting babies born without a small gland called the thymus, which produces T cells needed to regulate the immune system. 

RELATED: Roivant lines up $3B upfront in Sumitomo Dainippon deal 

Enzyvant is owned by Roivant, but it's expected to become a subsidiary of Sumitomo Dainippon Pharma after the drugmaker ponied up $3 billion upfront to buy Roivant’s stake in five of its "Vant" startups. The deal would take over Roivant's stake in Myovant, Urovant, Enzyvant, Altavant and an as-yet-unidentified Vant. 

The Vants covered by the first stage of the deal have multiple late-phase assets. Enzyvant has RVT-801, while Myovant and Urovant plan to file for FDA approval of their lead candidates—uterine fibroid drug relugolix and overactive bladder treatment vibegron, respectively—by the end of the financial year.