A Phase 1 Multiple Ascending Dose Study to Evaluate the Safety, Tolerability, and Pharmacokinetics of ManNAc in Subjects With Primary Podocyte Diseases

Kidney Disease Clinical Trial

Official title: A Phase 1 Multiple Ascending Dose Study to Evaluate the Safety, Tolerability, and Pharmacokinetics of ManNAc in Subjects With Primary Podocyte Diseases

Status Completed

Clinical Trial Summary

Three kidney diseases that affect both children and adults are minimal change disease (MCD), focal segmental glomerulosclerosis (FSGS) and membranous nephropathy (MN). These diseases are characterized by proteinuria (protein in the urine) and in the cases of FSGS and membranous nephropathy, a tendency to progressive scarring of the glomerulus (the filtering units of the kidneys) that leads to end-stage kidney disease. Several therapies are available for these diseases, but these therapies do not provide lasting reduction in proteinuria for many subjects. In the current study, carried out at the NIH Clinical Center, we are testing a new therapy, ManNAc. ManNAc is a naturally occurring uncharged sugar that cells use to produce negatively charged sialic acid. Kidney cells attach sugars such as sialic acids to proteins and lipids (resulting in glycans), and these assist in cell function. Mouse models of the inherited muscle disease GNE myopathy, which is due to sialic acid deficiency on muscle glycans, responded favorably to oral ManNAc therapy and a clinical trial of ManNAc is ongoing in GNE myopathy subjects. There is evidence that some subjects with MCD, FSGS or MN do not put enough sialic acids on glomerular proteins and so ManNAc therapy may increase sialic acid production and sialylation of glomerular proteins in these subjects. For the present study, we will recruit 12 subjects who have MCD, FSGS or MN. Each subject will stay at the NIH Clinical Center for 11 days to receive oral ManNAc. The primary purposes of the study are to determine: 1) the safety of ManNAc in subject s with kidney disease; and 2) the ManNAc and sialic acid metabolism related to ManNAc in subjects with kidney disease. Concentrations of ManNAc and sialic acid will be measured in plasma at various times before and after dosing. If this study suggests that ManNAc is safe in subject with kidney disease, the results will be used to plan a longer-term study to determine whether it is effective at reducing proteinuria....

Clinical Trial Description

Background. ManNAc (N-acetyl D-mannosamine) is an uncharged monosaccharide that is the biologic precursor of N-acetyl neuraminic acid (Neu5Ac, sialic acid). Sialic acids are the negatively charged, terminal monosaccharides of carbohydrate chains that are attached to glycoproteins and glycolipids (glycans). Most glycans serve cellular signaling functions, and frequently appear on the cell surface or are secreted into the circulation. ManNAc is currently in development as a therapy for the rare muscular dystrophy, GNE Myopathy (also called HIBM, hereditary inclusion body myopathy), caused by deficiency of GNE, the key enzyme in sialic acid synthesis (clinicaltrials.gov; NCT01634750).

A Phase 1a trial was completed and a Phase 2 trial for ManNAc for GNE myopathy subjects has been initiated through efforts of NCATS (TRND program; PI: Dr. Carrillo-Carrasco) and NHGRI (Dr. Huizing, Dr. Malicdan; Sponsor: Dr. Gahl), most of whom are Associate Investigators on this protocol. The NHGRI basic research group has documented podocytopathy, glomerular protein hyposialylation and severe proteinuria in mice deficient in GNE and found that their podocyte ultrastructure improved, sialylation increased and proteinuria decreased with oral ManNAc therapy. Human kidney biopsy tissue from subjects with various primary podocyte diseases, including minimal change disease (MCD), focal segmental glomerulosclerosis (FSGS) and membranous nephropathy (MN), also showed glomerular hyposialylation (manuscript in preparation).

Purpose. We propose to carry out a Phase 1 escalating dose study to evaluate the safety, tolerability, and pharmacokinetics of ManNAc in nephrotic subjects with primary podocyte diseases.

Subjects. We propose to enroll 12 subjects with MCD, FSGS or MN. Up to 24 total subjects may be enrolled to accomodate screening failures and withdrawals, for a total of 12 subjects receiving at least one dose of the study drug. We will recruit subjects in 4 groups (2-3 subjects each) grouped by estimated glomerular filtration rate (eGFR).

Intervention. This dose escalation study will involve two progressive ManNAc dose cohorts (each with N= 6) of 3,000 mg/day and 6,000 mg/day. Drug exposure will occur in a single dose phase, involving one dose of oral ManNAc followed by a 72 hour pharmacokinetics and safety study, and a multiple dose phase, involving ManNAc administered two times/day for 5 days. Dose escalation will occur when the lower dose is assessed safe in all subjects by a Safety Review Committee.

Outcomes. We will assess safety by self-reported symptoms and by standard laboratory testing. Pharmacokinetics will be analyzed using plasma ManNAc and Neu5Ac (sialic acid) levels. The effects of reduced eGFR on these parameters will be assessed. While the study duration is short and there is no placebo control, the effect of ManNAc therapy on proteinuria, from the baseline to the end of the extension phase, will be examined on a research basis. ;

Related Conditions & MeSH terms

• Kidney Disease
• Kidney Diseases

• NCT number: NCT02639260
• Study type: Interventional
• Source: National Institutes of Health Clinical Center (CC)
• Status: Completed
• Phase: Phase 1
• Start date: July 7, 2016
• Completion date: June 5, 2018