Immunoregulation with levamisole in children with frequently relapsing steroid responsive nephrotic syndrome

Population pharmacokinetics of levamisole in children with steroid-sensitive nephrotic syndrome

AIM

The aim was to investigate the population pharmacokinetics of levamisole in children with steroid-sensitive nephrotic syndrome.

METHODS

Non-linear mixed effects modelling was performed on samples collected during a randomized controlled trial. Samples were collected from children who were receiving 2.5 mg kg(-1) levamisole (or placebo) orally once every other day. One hundred and thirty-six plasma samples were collected from 38 children from India and Europe and included in the analysis. A one compartment model described the data well.

RESULTS

The apparent clearance rate (CL/F) and distribution volume (V/F) were 44 l h(-1) 70 kg(-1) and 236 l 70 kg(-1) , respectively; estimated interindividual variability was 32-42%. In addition to allometric scaling of CL/F and V/F to body weight, we identified a significant proportional effect of age on CL/F (-10.1% per year). The pharmacokinetics parameters were not affected by gender, tablet strength or study centre. The median (interquartile range) maximum plasma concentration of levamisole was 438.3 (316.5-621.8) ng ml(-1) , and the median area under the concentration-time curve was 2847 (2267-3761) ng ml(-1) h. Median tmax and t½ values were 1.65 (1.32-2.0) h and 2.60 (2.06-3.65) h, respectively.

CONCLUSIONS

Here, we present the first pharmacokinetic data regarding levamisole in children with steroid-sensitive nephrotic syndrome. The pharmacokinetic profile of levamisole in children was similar to findings reported in adults, although the elimination rate was slightly higher in children.

Experience with levamisole in frequently relapsing, steroid-dependent nephrotic syndrome

This was a controlled prospective study on the use of an immunomodulator drug, levamisole, in the treatment of frequently relapsing, steroid-dependent (FR/SD) idiopathic nephrotic syndrome. The study was started on 1 January 2001 and completed on 31 December 2003. There were two groups: a treatment group who received levamisole (2.5 mg/kg) on alternate days for 1 year and a control group who received low-dose prednisolone only (<0.5 mg/kg) on alternate days for 1 year. There were a total of 56 patients (32 in the treatment group and 24 in the control group). The male to female ratio was 1.66:1 in both groups. The mean age upon initial diagnosis was 3.3 years in the levamisole group versus 4.3 years in the control group. The mean duration from diagnosis to the start of the second line treatment was 3.2 years in the levamisole group versus 2.8 years in the control group. The relapse rate and the total cumulative dose of prednisolone during the year prior to second line therapy was compared to that during the year following the institution of second line therapy in 56 patients. The mean relapse rate was reduced more significantly in the levamisole group. It was reduced by 0.29 versus 0.11 relapses/patient/month in the control group (P =0.0001). The mean cumulative dose of steroids was also reduced more significantly in the levamisole group. It was reduced by 293 versus 102 mg/m(2)/month in the control group (P <0.0001). Therapy failure was seen in 3/32 (9.4%) in the levamisole group versus 12/24 (50%) in the control group. Of the patients, 20/32 (62.5%) using levamisole were relapse-free in the follow-up year post therapy, while no patient was relapse-free in the control group over the same period. No major adverse effects of levamisole were seen. The cost of levamisole therapy was estimated to be US$ 25 per year for a 20-kg body weight child. Thus, we concluded that levamisole is a highly efficacious, safe and easily affordable initial therapy for FR/SD idiopathic nephrotic syndrome.

Levamisole in steroid-sensitive nephrotic syndrome of childhood: the lost paradise?

Among the different drugs used for sparing steroids in steroid-sensitive nephrotic syndrome (SSNS) with frequent relapses and steroid dependency, levamisole is the least toxic and the least expensive. However, it is neither approved for this indication nor widely used in Europe. This may be explained by the difficulty in obtaining levamisole in some countries and the lack of good quality evidence for its effectiveness. Evidence is limited to three clinical trials that all suffered from methodological limitations. Statistical synthesis of these trials showed that levamisole reduces the risk of a relapse during treatment (relative risk 0.60, 95% confidence interval 0.45-0.79). From the available information, no conclusions can be drawn on the steroid-sparing effect, the long-term efficacy, and safety, as well as possible differences in efficacy in different subgroups of SSNS patients. The confirmation of a favorable effect of levamisole on the reduction of the frequency of relapses and on sparing steroids in an adequately powered, double-blind, placebo-controlled, randomized, multi-center clinical trial will promote consensus on the place of levamisole in the treatment of SSNS of childhood. Follow-up should be at least 1 year to evaluate long-term efficacy and side effects. If the results of such a clinical trial confirm the beneficial effects of levamisole in nephrotic syndrome, this may allow registration for this indication and interest companies other than Jansen-Cilag, which only recently has decided to stop its production.

Long-term effects of levamisole treatment in childhood nephrotic syndrome

The effects of levamisole treatment on long-term outcome were evaluated in a retrospective study of frequently-relapsing (FRNS, n=15), steroid-dependent (SDNS, n=13), and steroid-resistant (SRNS, n=6) nephrotic syndrome in 34 children (21 boys, 13 girls, mean age 5.0+/-3.4 years) during a 60-month follow-up period. The definition of frequent relapses was > or = 4 relapses per year. The current relapse was treated with prednisolone 60 mg/m2 per day for 4 weeks, then with 40 mg/m2 every other day for 4 weeks, after which the dose was tapered by 10 mg weekly. From the beginning of the 5th week, levamisole was introduced at a dose of 2 mg/kg per day. The duration of levamisole treatment was 17+/-7 months. Before starting levamisole treatment the mean level of proteinuria was 2.17+/-1.34 g/day and the relapse rate was 4.41/year. By the end of levamisole therapy, proteinuria had fallen to 0.142+/-0.211 g/day and the relapse rate to 0.41/year. No relapse occurred in 23 of the 34 patients during levamisole treatment. In the 24-month follow-up period after the discontinuation of levamisole, 28 children remained in total remission, while 6 had relapses. The cumulative steroid dose before levamisole therapy was 7,564.4+/-3,497.1 mg/year and following the introduction of levamisole 1,472.9+/-1,729.9 mg/year (P<0.0001). We observed reversible neutropenia in 5 patients, but no other side effects were seen. Our findings suggest that in FRNS and SDNS levamisole significantly reduces both the relapse rate and the cumulative steroid dose; therefore, it could be recommended for these patients. In SRNS patients it has also some benefit because proteinuria and the cumulative steroid dose could be reduced significantly.

Levamisole: might it be used in treatment and prevention of atopic diseases?

As an antihelmintic and Th1-biased immunostimulant, levamisole has been used to restore impaired cell mediated immunity. We sought to explore whether the Th1 driving effect of levamisole may also have an influence on the course of allergic diseases, by shifting the Th2 dominant immunity more toward Th1-mediated response. BALB/c mice were sensitized intraperitoneally on days 0, 7, and 15 with ovalbumin (OVA). After the sensitization, they were challenged intranasally with OVA once a day for 6 consecutive days. Levamisole (2.5 mg/kg) was administered orally three times a week during sensitization and challenge. After the last challenge, differential cell counts were performed, and IL-4 and IFNgamma levels were measured in the bronchoalveolar lavage fluids (BALF). Serum total IgE level was determined, and lungs were examined histologically. The present study establishes that mice administered with oral levamisole gave significantly lower IL-4 levels on sensitization with OVA; however, IFNgamma production, eosinophil infiltration, and serum IgE levels remained unaffected. In conclusion, use of levamisole may have important implications in the management of the allergic inflammation.

Management of minimal lesion glomerulonephritis: evidence-based recommendations

The treatment of idiopathic minimal lesion disease in children has been extensively studied in randomized controlled trials, however, there is less information available for adults. This article summarizes evidence-based recommendations for management. The first attack should be treated with prednisone or prednisolone at 60 mg/m2 per day (up to a maximum of 80 mg/day) for four to six weeks, followed by 40 mg/m2 of prednisone every other day for another four to six weeks (grade A). Relapse should be treated with 60 mg/m2/day of prednisone (up to 80 mg/day) only until the urine becomes protein free for three days, and then an alternate day regimen of 40 mg/m2 should be used for another month (grade A). Patients with frequently relapsing disease will have a significant reduction in relapse frequency after eight weeks of an alkylating agent (grade A). Less rigorous studies have suggested benefit with long-term, alternate-day corticosteroid (grade D) or the antihelminthic agent levamisole (grade D). For patients with steroid-dependent disease, an 8- or 12-week course with cyclophosphamide can induce remission (grade D). In true steroid-resistant disease, observational studies have suggested that a course of cyclosporine may sometimes induce remission or restore steroid responsiveness (grade D). Large retrospective studies in adults suggest that therapeutic response is slower than in children, but adults experience fewer relapses and more prolonged remission.