Effects of Fenofibrate Therapy in Diabetic Nephropathy

In this single-centre, open label study, 300 adults with DN will be recruited over 3 years. Following screening and baseline metabolic evaluations, eligible subjects will be treated with fenofibrate for 30-days and re-assessed.

4.1 Study Visits and Procedures Subjects will have their written informed consent taken during Visit 1 at the SGH Clinical Trials Research Centre (CTRC) and undergo screening and baseline assessments. Eligible subjects will return within the next 14 days for the initiation of study drug (Visit 2). The post-treatment and final visit (Visit 3) will take place 30 ± 7 days after Visit 2. Details of study visits are described in Table 1 (Refer study protocol).

4.1.1 VISIT 1: Informed Consent and Screening Interested patients will be scheduled for their first study visit (Visit 1) at SGH CTRC. Written informed consent will be taken by the principal or co-investigators assigned by the PI. After consent has been taken, study procedures in Table 1 will be performed. The PI or Co-Is assigned by the PI, will review screening results to determine whether subjects are eligible to continue with the study.

4.1.2 VISIT 2: Initiation of Study Drug

Subjects who satisfy the inclusion and exclusion criteria will return to the CTRC within the next 14 days to receive the study drug, fenofibrate. Fenofibrate is to be taken orally for 30 days. The dose of fenofibrate will be adjusted based on the estimated CrCl during Visit 1 as below.

CrCl (ml/min) Fenofibrate Dosage > 60 300mg/day 30-59 100 mg/day < 30 Contraindicated

Subjects will take the first dose of fenofibrate under supervision of the clinical research coordinator at SGH CTRC. They will be given a drug diary to record their intake.

Before the initiation of the study drug, subjects will first head over to Singapore Eye Research Institution (SERI) or Singapore National Eye Centre (SNEC)) for eye tests as mentioned in the following paragraphs.

Fundus Photography, conventional OCT and Assessment and grading of DR The presence and severity of DR or DME will be assessed from digital fundus photographs and OCT. Following pupillary dilation, 7-field ETDRS photography using a non-mydriatic 45º fundus cameras will be obtained for each eye. The modified Wisconsin protocol will be used for DR grading. DR will be considered present if any characteristic lesion as defined by the ETDRS severity scale is present: microaneurysms (MA), hemorrhages, cotton wool spots, intraretinal microvascular abnormalities (IRMA), hard exudates (HE), venous beading, and new vessels. For each eye, a retinopathy severity score will be assigned according to a scale modified from the Airlie House classification system. Macular edema is defined by hard exudates in the presence of MA and blot hemorrhage within 1 disc diameter from the foveal center or presence of focal photocoagulation scars in the macular area. Clinically significant macular edema (CSME) is considered present when the macular edema involved is within 500 mm of the foveal center or if focal photocoagulation scars are present in the macular area. DR is categorized as minimal non-proliferative DR (level 20), mild non-proliferative DR (level 35), moderate non-proliferative DR (level 43 through 47), severe NPDR (level 53), and proliferative retinopathy (>60). Vision-threatening retinopathy is defined as the presence of severe NPDR, PDR, or CSME. Presence of DME (centre involving and non centre involving) and central retinal thickness will also be assessed on OCT

Ultrawide field imaging Stereoscopic 200-degree-field ultrawide field images of each subject will be obtained using the Optos P200MA instrument. Unlike traditional fundus cameras, Optos imaging relies on proper eye positioning by the imager and correct patient fixation on a target, rather than the imager viewing the retinal structures for focus. The UWF200 images are centered on the fovea, covering approximately 25% and 82%, respectively, of the retinal area, including the optic disc, macula, and major vascular arcades. Grading of UWF imaging will be performed using the ETDRS protocol to determine the presence and severity of the following lesions: hemorrhages, microaneurysms, or both (H/Ma); intraretinal microvascular abnormalities (IRMA); venous beading (VB); cotton wool spots; hard exudates; retinal thickening; new vessels on the disc; new vessels elsewhere (NVE) on the retina; preretinal hemorrhage; vitreous hemorrhage; and traction retinal detachment. This test will be optional.

Optical Coherence Tomography (OCT) and Optical Coherence Tomography Angiography (OCTA) Spectral Domain Optical Coherence Tomography and optical coherence tomographic angiography will be performed in both eyes to obtain scans of the macular, macular thickness, retinal nerve fiber thickness optic disc, and optic nerve head.

4.1.3 VISIT 3: 4-Week Post-Treatment Visit

Visit 3 will take place 30 ± 7 days from Visit 2. Subjects who are still on the study drug should continue take the study drug on the morning of Visit 3 with plain water. Subjects will be assessed to quantify changes in metabolic fuel utilization after treatment with fenofibrate. These changes are determined based on metabolomic profiling of acyl-carnitines, organic acids and amino acid, indirect calorimetry measurements and the eye tests. The list of procedures performed is listed in Table 1.

SAMPLE COLLECTION

Up to a total of 47 ml (~3.2 tablespoons) of blood and 90 ml (~6.0 tablespoons) of urine will be collected for the entire study. During Visit 1 (Screening), approximately 25 ml (~1.7 tablespoons) of blood and 30 ml (~2.0 tablespoon) of urine will be collected. During Visit 2 (Dosing visit), 30 ml of urine will be collected and during Visit 3 (post-treatment & final visit), approximately 22ml (~1.5 tablespoon) of blood and 30 ml (~2.0 tablespoon) of urine will be collected.

Subjects who developed drug-related adverse reactions may require additional blood and urine taken for clinical assessment.

LABORATORY MEASUREMENTS

A) Blood Chemistry Screening and standard laboratory tests including full blood count, Potassium, Creatinine. alanine transaminase, aspartame transamniase, β-human chorionic gonadotropin, CK, lipid panel, glucose and HbA1c will be measured in the clinical laboratory using standard methods.

B) Metabolomic Profiling Metabolomic profiling of lipids, acylcarnitines (ACs), organic acids and ketones will be measured using liquid and gas chromatography and tandem mass spectrometry (LC-MS/MS and Gas Chromatography-MS/MS) at the Duke-National University of Singapore metabolomics laboratory.

ACs represent intermediaries of metabolic fuel oxidation and provides a "snap-shot" of in vivo metabolism at the cellular level. The measurement of the various long-, intermediate-chain ACs provide an indicator of fatty acid oxidation efficiency. Ceramides are toxic lipid intermediaries that are implicated in the pathogenesis of insulin resistance. Lactate, pyruvate, succinate, fumarate, malate, alpha-ketoglutarate and citrate are organic acids involved in tricarboxylic acid cycle activity. Beta hydroxybutyrate is a ketone which will also be measured with the organic acids.

C) Urine Protein Excretion

Urine ACR and PCR will be performed to quantify urine protein excretion.