---
title: "Non-retinoid RBP4 antagonist AKR-XI-85 as a candidate therapy for Stargardt disease"
id: "biorxiv-19-a-non-retinoid-triazolopyrimidine-rbp4-antagonist-for-the-treatment-of"
canonical_url: "https://medichelpline.com/clinical-feed/biorxiv-19-a-non-retinoid-triazolopyrimidine-rbp4-antagonist-for-the-treatment-of"
content_type: "clinical_feed_article"
specialty: "General"
source_name: "bioRxiv (Biomedical Preprints)"
source_url: "https://www.biorxiv.org/content/10.64898/2026.09.14.751502v1?rss=1"
published_at: "2026-09-21T12:00:00.000Z"
evidence_level: "Verified Feed"
license: "CC-BY-NC-4.0 / Informational Use"
---
# Non-retinoid RBP4 antagonist AKR-XI-85 as a candidate therapy for Stargardt disease
## Provenance & Clinical Metadata
- **Canonical URL:** https://medichelpline.com/clinical-feed/biorxiv-19-a-non-retinoid-triazolopyrimidine-rbp4-antagonist-for-the-treatment-of
- **Specialty:** [General](https://medichelpline.com/clinical-feed/general.md)
- **Primary Source:** bioRxiv (Biomedical Preprints)
- **Source URL:** [Original Journal Publication](https://www.biorxiv.org/content/10.64898/2026.09.14.751502v1?rss=1)
- **Published At:** 2026-09-21T12:00:00.000Z
- **Evidence Rating:** Verified Feed
## Executive GIST (TL;DR)
- Stargardt disease is a juvenile retinal dystrophy driven by accumulation of cytotoxic **lipofuscin** in the retinal pigment epithelium (RPE), leading to photoreceptor loss and blindness. - The principal toxic components of lipofuscin are **bisretinoids**, whose synthesis depends on retinol traffic from blood to retina. - Retinol transport to the eye requires interaction between **Retinol-Binding Protein 4 (RBP4)** and serum **Transthyretin (TTR)**; blocking this pathway can reduce retinal retinol load. - The authors previously developed RBP4 antagonists but some chemotypes had off-target activities that limited development. - This report describes pharmacological characterization of a **non-retinoid triazolopyrimidine** series, highlighting the lead compound **AKR-XI-85** and analogs as selective RBP4 antagonists. - AKR-XI-85 showed favorable in vitro and in vivo efficacy, with pharmacokinetic properties and absence of reported limiting off-target activity in the paper. - In an Abca4-/- mouse model (a model relevant to Stargardt disease), chronic dosing produced a sustained reduction in serum **RBP4** levels and a ~70% reduction in accumulation of **A2E**, a key bisretinoid component of lipofuscin. - The compound reduced retinoid delivery to the retina via disruption of the TTR–RBP4–retinol complex, consistent with the proposed mechanism to limit bisretinoid formation. - The authors propose AKR-XI-85 as an attractive drug candidate for Stargardt disease and other lipofuscin-dependent retinopathies, noting the study is a preprint and not peer reviewed. - Funding for the work included the Gund-Harrington National Initiative; authors declared no competing interests.
## Clinical Analysis & Structured Key Points
A non-retinoid triazolopyrimidine RBP4 antagonist for the treatment of Stargardt disease | bioRxiv Skip to main content New Results A non-retinoid triazolopyrimidine RBP4 antagonist for the treatment of Stargardt disease K. Alison Rinderspacher , Andras Varadi , Boglarka Racz , Andrew S. Wasmuth , Shi-Xian Deng , Patricia Weber , Donald W. Landry , Peter R. Bernstein , View ORCID Profile Konstantin Petrukhin doi: https://doi.org/10.64898/2026.09.14.751502 K. Alison Rinderspacher 1 Columbia University Irving Medical Center; Find this author on Google Scholar Find this author on PubMed Search for this author on this site Andras Varadi 1 Columbia University Irving Medical Center; Find this author on Google Scholar Find this author on PubMed Search for this author on this site Boglarka Racz 1 Columbia University Irving Medical Center; Find this author on Google Scholar Find this author on PubMed Search for this author on this site Andrew S. Wasmuth 1 Columbia University Irving Medical Center; Find this author on Google Scholar Find this author on PubMed Search for this author on this site Shi-Xian Deng 1 Columbia University Irving Medical Center; Find this author on Google Scholar Find this author on PubMed Search for this author on this site Patricia Weber 2 Harrington Discovery Institute Therapeutics Development Center Find this author on Google Scholar Find this author on PubMed Search for this author on this site Donald W. Landry 1 Columbia University Irving Medical Center; Find this author on Google Scholar Find this author on PubMed Search for this author on this site Peter R. Bernstein 2 Harrington Discovery Institute Therapeutics Development Center Find this author on Google Scholar Find this author on PubMed Search for this author on this site Konstantin Petrukhin 1 Columbia University Irving Medical Center; Find this author on Google Scholar Find this author on PubMed Search for this author on this site ORCID record for Konstantin Petrukhin For correspondence: kep4{at}cumc.columbia.edu Abstract Info/History Metrics Preview PDF Abstract Stargardt disease is a juvenile-onset retinal dystrophy characterized by the buildup of cytotoxic lipofuscin deposits in the retinal pigment epithelium (RPE), leading to photoreceptor degeneration and eventual blindness. Currently, there are no FDA-approved treatments for Stargardt disease. Bisretinoids, byproducts of the visual cycle, are the major cytotoxic components of the lipofuscin deposits, and bisretinoid synthesis relies on the traffic of retinol from the bloodstream to the retina. Selective targeting of the key retinol transporter, Retinol-Binding Protein 4 (RBP4), offers an appealing strategy for halting the buildup of lipofuscin in the RPE and arresting the progression of Stargardt disease. Retinol delivery depends on RBP4 interaction with another serum protein, Transthyretin (TTR). We previously reported several libraries of RBP4 antagonists that effectively blocked the association of the TTR-RBP4-retinol tertiary complex, thereby lowering the overall retinol load in the retina; however, some chemotypes displayed off-target activity that warranted further optimization. Here, we report the pharmacological characterization of AKR-XI-85 and its analogs as promising non-retinoid small-molecule RBP4 antagonists. AKR-XI-85 displayed excellent in vitro and in vivo efficacy and desirable pharmacokinetic properties without any limiting off-target activity. In Abca4-/- mice, chronic dosing of the compound induced a prolonged reduction in serum RBP4 levels and achieved a dramatic, 70 % reduction in the accumulation of A2E, a critical component of toxic lipofuscin. As such, AKR-XI-85 may be an attractive drug candidate for the treatment of Stargardt disease and other lipofuscin-dependent retinopathies. Competing Interest Statement The authors have declared no competing interest. Funder Information Declared Gund-Harrington National Initiative , TA-NMT-1115-0690-COLU-GH Copyright The copyright holder for this preprint is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. All rights reserved. No reuse allowed without permission. Back to top Previous Next Posted September 21, 2026. Download PDF Email Thank you for your interest in spreading the word about bioRxiv. NOTE: Your email address is requested solely to identify you as the sender of this article. Your Email * Your Name * Send To * Enter multiple addresses on separate lines or separate them with commas. You are going to email the following A non-retinoid triazolopyrimidine RBP4 antagonist for the treatment of Stargardt disease Message Subject (Your Name) has forwarded a page to you from bioRxiv Message Body (Your Name) thought you would like to see this page from the bioRxiv website. Your Personal Message CAPTCHA This question is for testing whether or not you are a human visitor and to prevent automated spam submissions. Share A non-retinoid triazolopyrimidine RBP4 antagonist for the treatment of Stargardt disease K. Alison Rinderspacher , Andras Varadi , Boglarka Racz , Andrew S. Wasmuth , Shi-Xian Deng , Patricia Weber , Donald W. Landry , Peter R. Bernstein , Konstantin Petrukhin bioRxiv 2026.09.14.751502; doi: https://doi.org/10.64898/2026.09.14.751502 Share This Article: Copy Citation Tools A non-retinoid triazolopyrimidine RBP4 antagonist for the treatment of Stargardt disease K. Alison Rinderspacher , Andras Varadi , Boglarka Racz , Andrew S. Wasmuth , Shi-Xian Deng , Patricia Weber , Donald W. Landry , Peter R. 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