Diabetic neuropathy and peptides — disease-modifying ambition versus what the trial record shows

Why this dossier exists

Diabetic neuropathy is the most common chronic complication of diabetes and, in 2026, still the indication with the longest graveyard of failed disease-modifying trials in peptide pharmacology. The 2017 American Diabetes Association position statement (Pop-Busui R, Boulton AJM, Feldman EL, Bril V, Freeman R, Malik RA, Sosenko JM, Ziegler D, Diabetes Care 2017, 40:136–154) catalogues a heterogeneous family of conditions — distal symmetric polyneuropathy (DSPN), cardiovascular and gastrointestinal autonomic neuropathy, focal mononeuropathies and mononeuritis multiplex, and proximal radiculoplexus neuropathy — that together affect on the order of half of patients with longstanding diabetes. The Tesfaye et al., Diabetes Care 2010, 33:2285–2293 Toronto consensus sets the diagnostic criteria the modern trial literature uses.

Standard of care in 2026 has a clear hierarchy and a clear ceiling. The hierarchy is glycemic control as the primary disease-modifying intervention, with symptomatic pharmacotherapy — pregabalin, gabapentin, duloxetine, venlafaxine, tricyclic antidepressants, opioids with reservations, and most recently the capsaicin 8% patch (Qutenza, FDA-approved for painful DPN of the feet in July 2020) — layered on top of it. The ceiling is that no FDA-approved therapy reverses or arrests the underlying nerve damage. The 2011 American Academy of Neurology evidence-based guideline (Bril V, England J, Franklin GM, Backonja M, Cohen J, Del Toro D, Feldman E, Iverson DJ, Perkins B, Russell JW, Zochodne D, Neurology 2011, 76:1758–1765) and its 2022 update both review treatments that address pain without modifying the natural history of the disease. Disease-modifying ambition is what the peptide conversation in diabetic neuropathy is actually about — and it is a conversation that has spent four decades producing more Phase 3 failures than approvals.

This dossier walks the peptide and peptide-adjacent evidence base for diabetic neuropathy, separates the trial-supported signals from mechanism extrapolation, and frames the entire conversation against the metabolic-control backbone that defines real-world outcomes. The honest read across the corpus: ARA-290 / cibinetide carries the most-mechanistically-novel design and the cleanest single Phase II disease-modifying signal in the indication; C-peptide replacement has the longest academic arc and the most expensive failure; and the GLP-1 class is producing the most consequential indirect benefit through glycemic and weight-related effects rather than through any direct neurotrophic mechanism.