C5 Convertase Blockade in Membranoproliferative Glomerulonephritis: A Single-Arm Clinical Trial

RATIONALE & OBJECTIVE

Primary membranoproliferative glomerulonephritis (MPGN) is a rare glomerulopathy characterized by complement dysregulation. MPGN progresses rapidly to kidney failure when it is associated with nephrotic syndrome. We assessed the effects of C5 convertase blockade in patients with MPGN and terminal complement activation.

STUDY DESIGN

Prospective off-on-off-on open-label clinical trial.

SETTING & PARTICIPANTS

Consenting patients with immune complex-mediated MPGN (n=6) or C3 glomerulonephritis (n=4) with sC5b-9 (serum complement membrane attack complex) plasma levels>1,000ng/mL and 24-hour proteinuria with protein excretion>3.5g identified from the Italian Registry of MPGN and followed up at the Istituto di Ricerche Farmacologiche Mario Negri IRCCS (Bergamo, Italy) between March 4, 2014, and January 7, 2015.

INTERVENTION

Anti-C5 monoclonal antibody eculizumab administered during 2 sequential 48-week treatment periods separated by one 12-week washout period.

OUTCOMES

Primary outcome was change in 24-hour proteinuria (median of 3 consecutive measurements) at 24 and 48 weeks.

RESULTS

Median proteinuria decreased from protein excretion of 6.03 (interquartile range [IQR], 4.8-12.4) g/d at baseline to 3.74 (IQR, 3.2-4.4) g/d at 24 weeks (P=0.01) and to 5.06 (IQR, 3.1-5.8) g/d (P=0.006) at 48 weeks of treatment, recovered toward baseline during the washout period, and did not significantly decrease thereafter. Hypoalbuminemia, dyslipidemia, and glomerular sieving function improved during the first treatment period. 3 patients achieved partial remission of nephrotic syndrome and all had undetectable C3 nephritic factors before treatment. Mean measured glomerular filtration rate was 69.7±35.2 versus 87.4±55.1 and 75.8±42.7 versus 76.6±44.1mL/min/1.73m² at the start versus the end of the first and second treatment periods, respectively, among all 10 study participants. Unlike C3, sC5b-9 plasma levels normalized during both treatment periods and recovered toward baseline during the washout in all patients.

LIMITATIONS

Single-arm design, small sample size.

CONCLUSIONS

Eculizumab blunted terminal complement activation in all patients with immune complex-mediated MPGN or C3 glomerulonephritis and nephrotic syndrome, but persistently reduced proteinuria in just a subgroup.

TRIAL REGISTRATION

Registered in the EU Clinical Trials Register with study no. 2013-003826-10.

Predominance of Clostridium difficile 027 during a five-year period in Bolzano, Northern Italy

Toxigenic Clostridium difficile is responsible for antibiotic-associated diarrhoea and other diseases. The increasing frequency and severity is attributed to highly-virulent ribotypes such as 027. The aim of the study was to collect epidemiological and molecular data for C. difficile isolates during 2009-2013 in the Central Hospital of Bolzano, Northern Italy. Stool samples from inpatients of the Bolzano Central Hospital were screened for toxins A and B, and C. difficile was cultured and tested for antibiotic susceptibility. PCRs were performed for genes of toxin A, toxin B, binary toxin and ribotyping. During the period 2009-13 from 320 patients (9% of patients tested) at least one stool sample proved positive for C. difficile toxins, and incidences for all hospital inpatients per 10,000 patient days (per 1,000 admissions) varied between 2.2 (1.5) and 4.3 (3.0). Out of 138 isolates (43% of total isolates were studied), 24 different ribotypes were identified. Isolates with ribotype 027 were predominant (38%), followed by 018 (13%) and 607 (10%). Whereas for ribotype 018 a significant decrease was seen during the five-year period, ribotype 027 increased significantly from 0% in 2009 to 64% in 2012, decreasing then to 10% in 2013. Isolates were sensitive to metronidazole and vancomycin, whereas isolates of the three major ribotypes were resistant to moxifloxacin. Our data indicates a significant change in C. difficile incidence rates and ribotype frequencies during the five-year period in the Central Hospital in Bolzano.