Nature Medicine Publishes REMODEL Trial: Semaglutide Missed Its Primary Kidney Imaging Endpoints, But Biopsy Data Point to Reduced Fibrosis

Nature Medicine published a randomized, placebo-controlled trial online October 1, 2026 examining how semaglutide affects the kidney at a mechanistic level in people with type 2 diabetes and chronic kidney disease, using imaging and tissue analysis rather than relying only on standard blood and urine measures of kidney function. The trial, registered as NCT04865770 and known as REMODEL, was led by Katherine R. Tuttle of Providence Inland Northwest Health and the University of Washington and Petter Bjornstad of the University of Washington and University of Colorado Anschutz Medical Campus, with co-authors from the University of Michigan, University Hospital of Lausanne, University Health Network in Toronto, and Novo Nordisk, which sponsored the trial and manufactures semaglutide.

REMODEL randomized 106 participants, 25 women and 81 men, to once-weekly subcutaneous semaglutide 1 mg or placebo for 52 weeks. To probe kidney-specific mechanisms, the trial combined multiparametric magnetic resonance imaging of the kidney with kidney biopsies in a subset of 33 participants, who underwent histology, and further subsets who underwent single-nucleus RNA sequencing (22 participants) and spatial transcriptomics (13 participants), comparing paired samples taken before and after treatment.

The trial's three coprimary outcomes were all MRI-based: kidney oxygenation measured by R2*, global kidney perfusion, and tissue inflammation measured by T1 mapping. According to the published results, none of these three coprimary measures differed significantly between the semaglutide and placebo groups, meaning the trial did not meet its primary imaging endpoints.

Secondary outcomes told a different story. The authors report that semaglutide, compared with placebo, significantly reduced the renal artery resistive index, a Doppler ultrasound-style measure of vascular resistance within the kidney, and stabilized the apparent diffusion coefficient on MRI, a finding the authors interpret as evidence that semaglutide prevented progression of kidney fibrosis over the 52 weeks. Secondary transcriptomic analyses from the biopsy substudies found pronounced effects of semaglutide on glomerular endothelial cells, the cells lining the kidney's filtering blood vessels, and spatial transcriptomic data showed fewer immune cells located near those endothelial cells in the semaglutide group.

The authors conclude that the mechanisms behind semaglutide's kidney protection, previously documented in outcomes trials such as FLOW, may include reduced vascular resistance, prevention of fibrosis, and improved molecular programs that support endothelial cell health, rather than the changes in oxygenation, perfusion, or inflammation that the trial's primary MRI endpoints were designed to detect. Because these conclusions rest on secondary and exploratory analyses in a 106-person trial, they describe potential biological mechanisms rather than a confirmed clinical effect on kidney function.

Several authors disclosed being employees of and holding shares in Novo Nordisk, which sponsored the trial; other authors disclosed consulting and research funding relationships with Novo Nordisk and other pharmaceutical companies. Semaglutide, marketed as Ozempic and Rybelsus for type 2 diabetes and Wegovy for chronic weight management, remains approved by the FDA, the European Medicines Agency, and Australia's Therapeutic Goods Administration for those indications. This mechanistic trial does not change that regulatory status and does not constitute treatment or dosing guidance; decisions about semaglutide use in chronic kidney disease should be made with a qualified clinician.