First analytical confirmation of drug-induced crystal nephropathy in felines caused by GS-441524, the active metabolite of Remdesivir

Abstract

GS-441524 is an adenosine nucleoside antiviral demonstrating significant efficacy in the treatment of feline infectious peritonitis (FIP), an otherwise fatal illness, resulting from infection with feline coronavirus. However, following the emergence of COVID-19, veterinary development was halted, and Gilead pursued clinical development of a GS-441524 pro-drug, resulting in the approval of Remdesivir under an FDA emergency use authorization. Despite lack of regulatory approval, GS-441524 is available without a prescription through various unlicensed online distributors and is commonly purchased by pet owners for the treatment of FIP. Herein, we report data obtained from the analytical characterization of two feline renal calculi, demonstrating the propensity for GS-441524 to cause renal toxicity through drug-induced crystal nephropathy in vivo. As definitive diagnosis of drug-induced crystal nephropathy requires confirmation of the lithogenic material to accurately attribute a mechanism of toxicity, renal stone composition and crystalline matrix were characterized using ultra-performance liquid chromatography photodiode array detection (UPLC-PDA), ultra-performance liquid chromatography mass spectrometry (LCMS), nuclear magnetic resonance (NMR) spectroscopy, X-ray powder diffraction (XRD), and Fourier-transform infrared spectroscopy (FTIR). This work serves to provide the first analytical confirmation of GS-441524-induced crystal nephropathy in an effort to support toxicologic identification of adverse renal effects caused by administration of GS-441524 or any pro-drug thereof.

Keywords: Coronavirus; Crystal nephropathy; Feline infectious peritonitis; GS-441524; Remdesivir; Renal toxicity.

Figure 1.

Stereo microscopy images demonstrating compact crystallization pattern of feline renal stone #1, indicative of homogenous nucleation of GS-441524.

Figure 2.

A) Mass spectra of GS-441524 analytical standard, renal stone #1, and renal stone #2 in both positive and negative ionization modes. Major peaks ≥ 1% total ion current (TIC) between 200–350 m/z are shown. B) Proposed fragmentation pattern for GS-441524 based on mechanistic investigations of remdesivir by Dadinaboyina et al. [19].

Figure 3.

UPLC-PDA comparative ultra-violet spectra of GS-441524 analytical standard, renal stone #1, and renal stone #2.

Figure 4.

Heteronuclear Multiple Quantum Coherence (HMQC) NMR spectrum of GS-441524 with corresponding carbon assignments.

Figure 5.

A) XRD diffractogram for renal stone #2 (top) and GS-441524 analytical standard (bottom) between 0–50°2θ. Complete XRD peak list available in supplementary material. B) FTIR spectra for renal stone #1 (top) and GS-441524 analytical standard (bottom). FTIR spectra for all samples and complete peak list available in supplementary material.