Open-Label Clinical Trials of Oral Pulse Dexamethasone for Adults with Idiopathic Nephrotic Syndrome

BACKGROUND

In adults with primary focal segmental glomerulosclerosis (FSGS), daily prednisone may induce complete remissions (CR) and partial remissions (PR), but relapses are frequent and adverse events are common.

METHODS

We carried out 2 open-label, uncontrolled trials to explore the efficacy and tolerability of pulse oral dexamethasone as an alternative to daily prednisone. We enrolled adult patients with proteinuria > 3.5 g/day despite the use of renin-angiotensin-aldosterone blockade. In the first trial, we enrolled 14 subjects with FSGS and administered 4 dexamethasone doses (25 mg/m2) daily for 4 days, repeated every 28 days over 32 weeks. The second trial involved a more intensive regimen. Eight subjects received 4 dexamethasone doses of 50 mg/m2 every 4 weeks for 12 weeks, followed by 4 doses of 25 mg/m2 every 4 weeks for 36 weeks; subjects were randomized to 2 doses every 2 weeks or 4 doses every 4 weeks.

RESULTS

In the first trial, we enrolled 13 subjects with FSGS and 1 with minimal change disease and found a combined CR and PR rate of 36%. In the second trial, we enrolled 8 subjects. The combined CR and PR rate was 29%. Analysis combining both trials showed a combined CR and PR rate of 33%. Adverse events were observed in 32% of subjects, with mood symptoms being most common. There were no serious adverse events related to the study.

CONCLUSION

We conclude that high dose oral dexamethasone is well tolerated by adults with idiopathic nephrotic syndrome and may have some efficacy.

Pirfenidone slows renal function decline in patients with focal segmental glomerulosclerosis

BACKGROUND AND OBJECTIVES

Pirfenidone is an orally available antifibrotic agent that has shown benefit in animal models of pulmonary and renal fibrosis and in clinical trials of pulmonary fibrosis, multiple sclerosis, and hepatic cirrhosis. Our objective was to determine whether pirfenidone slows the loss of renal function in focal segmental glomerulosclerosis.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

An open-label trial was performed to evaluate the safety and efficacy of pirfenidone in patients with idiopathic and postadaptive focal segmental glomerulosclerosis. The monthly change in estimated GFR, expressed as ml/min per 1.73 m2, was compared between the baseline period and the treatment period. During both periods, patients received angiotensin antagonist therapy if tolerated. Twenty-one patients were enrolled, and 18 patients completed a median of 13 mo of pirfenidone treatment.

RESULTS

The monthly change in GFR improved from a median of -0.61 ml/min per 1.73 m2 (interquartile range -1.31 to -0.41) during the baseline period to -0.45 ml/min per 1.73 m2 (interquartile range -0.78 to -0.16) with pirfenidone therapy. This change represents a median of 25% improvement in the rate of decline (P < 0.01). Pirfenidone had no effect on BP or proteinuria. Adverse events attributed to therapy included dyspepsia, sedation, and photosensitive dermatitis.

CONCLUSIONS

It is concluded that pirfenidone is an attractive candidate for placebo-controlled trials in patients with progressive chronic kidney disease.

Molecular identification of SV40 infection in human subjects and possible association with kidney disease

Simian virus 40 (SV40), a monkey polyomavirus that is believed to have entered the human population through contaminated vaccines, is known to be renotropic in simians. If indeed SV40 is endemic within the human population, the route of transmission is unknown. It was therefore hypothesized that SV40 might be renotropic in humans and be detected more frequently in samples obtained from patients with kidney diseases. This study found that typical polyomavirus cytopathic effects (CPE) were present and SV40 T antigen was detected in CV-1 cells cultured with peripheral blood mononuclear cells (PBMC) or urinary cells obtained from patients with kidney disease and healthy volunteers. DNA sequences homologous to the SV40 viral regulatory genome were detected by PCR in urinary cells from 15 (41%) of 36 patients with focal segmental glomerulosclerosis (FSGS), 2 (10%) of 20 patients with other kidney diseases, and 1 (4%) of 22 healthy volunteers (FSGS compared with other glomerular disease, P < 0.02; FSGS compared with healthy volunteers, P = 0.003). SV40 viral regulatory region genome was detected from PBMC at similar frequencies in patients with FSGS (35%), other glomerular diseases (20%), and healthy volunteers (22%). SV40 genome was detected by PCR in kidney tissues from 17 (56%) of 30 of patients with FSGS and 4 (20%) of 20 patients with minimal change disease and membranous nephropathy (P < 0.01). Considerable genetic heterogeneity of the viral regulatory region was detected, which argues against laboratory contamination. SV40 genome was localized to renal tubular epithelial cell nuclei in renal biopsies of patients with FSGS by in situ hybridization. This study demonstrates for the first time that human kidney can serve as a reservoir for SV40 replication and that SV40 may contribute to the pathogenesis of kidney disease, particularly FSGS.

TGF-beta and fibrosis

Transforming growth factor-beta (TGF-beta) isoforms are multifunctional cytokines that play a central role in wound healing and in tissue repair. TGF-beta is found in all tissues, but is particularly abundant in bone, lung, kidney and placental tissue. TGF-beta is produced by many but not all parenchymal cell types, and is also produced or released by infiltrating cells such as lymphocytes, monocytes/macrophages, and platelets. Following wounding or inflammation, all these cells are potential sources of TGF-beta. In general, the release and activation of TGF-beta stimulates the production of various extracellular matrix proteins and inhibits the degradation of these matrix proteins, although exceptions to these principles abound. These actions of TGF-beta contribute to tissue repair, which under ideal circumstances leads to the restoration of normal tissue architecture and may involve a component of tissue fibrosis. In many diseases, excessive TGF-beta contributes to a pathologic excess of tissue fibrosis that compromises normal organ function, a topic that has been the subject of numerous reviews [1-3]. In the following chapter, we will discuss the role of TGF-beta in tissue fibrosis, with particular emphasis on renal fibrosis.

Peritonitis due to Rhizopus in a patient undergoing continuous ambulatory peritoneal dialysis

A 61-year-old man who had end-stage renal disease secondary to diabetes mellitus and hypertension developed peritonitis due to infection with Rhizopus as a complication of receiving continuous ambulatory peritoneal dialysis (CAPD). At the onset of infection, the patient was neither acidemic nor hyperglycemic; in addition, deferoxamine had not been administered and Elastoplast dressings had not been applied. The infection occurred after the technique for disinfection of the catheter used for CAPD had been changed. The catheter was removed, and therapy with amphotericin B was initiated. Although the patient died of apparently unrelated causes, an autopsy revealed active fungal infection with multiple abscesses and superficial invasion of the ileal wall.