Comment from NuSirt Sciences, Inc.
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Summary: Michael B. Zemel, Chief Scientific Officer of NuSirt Sciences, Inc., submits information regarding TRIPLN(TM), a fixed-dose combination of leucine, metformin, and sildenafil, as a candidate for drug repurposing in cardiometabolic diseases. He argues that while TRIPLN(TM) is a novel combination rather than a single drug gaining a new use, it aligns with the FDA's interest in repurposing established agents and highlights specific regulatory and commercial barriers facing such programs.
This submission is provided in response to FDA's Request for Information on Drug Repurposing for Unmet Medical Needs (Docket No. FDA-2026-N-4492). It identifies TRIPLN(TM), a fixed-dose combination of leucine, metformin, and low-dose sildenafil, as a candidate relevant to FDA's stated interest in repurposing approved-drug safety data toward new uses in metabolic disease, one of the priority areas the Agency has specifically identified.
TRIPLN(TM) is not the paradigm case the RFI's core example describes — a single approved drug gaining a new use via supplemental application — since it is a novel, three-component fixed-dose combination pursued through its own development pathway. We believe it is nonetheless squarely relevant to the Agency's broader stated interest in candidates “across the evidentiary spectrum,” including those with preliminary but real clinical signals, and we submit this both to identify the candidate and to offer observations on barriers facing this category of repurposing program — novel combinations of established, off-patent agents — which differ somewhat from the single-drug/single-new-use case the RFI most directly addresses.