A randomized clinical trial indicates that levamisole increases the time to relapse in children with steroid-sensitive idiopathic nephrotic syndrome
Authors: Mariken P. Gruppen, Antonia H. Bouts, Marijke C. Jansen-van der Weide, Maruschka P. Merkus, Aleksandra Zurowska, Michal Maternik, Laura Massella, Francesco Emma, Patrick Niaudet, Elisabeth A.M. Cornelissen, Thierry Schurmans, Ann Raes, Johan van de Walle, Mieke van Dyck, Ashima Gulati, Arvind Bagga, Jean-Claude Davin
Journal: Kidney International (2017)

Levamisole has been considered the least toxic and least expensive steroid-sparing drug for preventing relapses of steroid-sensitive idiopathic nephrotic syndrome (SSINS). However, evidence for this is limited as previous randomized clinical trials were found to have methodological limitations. Therefore, we conducted an international multicenter, placebo-controlled, double-blind, randomized clinical trial to reassess its usefulness in prevention of relapses in children with SSINS. The efficacy and safety of one year of levamisole treatment in children with SSINS and frequent relapses were evaluated. The primary analysis cohort consisted of 99 patients from 6 countries. Between 100 days and 12 months after the start of study medication, the time to relapse (primary endpoint) was significantly increased in the levamisole compared to the placebo group (hazard ratio 0.22 [95% confidence interval 0.11–0.43]). Significantly, after 12 months of treatment, six percent of placebo patients versus 26 percent of levamisole patients were still in remission. During this period, the most frequent serious adverse event (four of 50 patients) possibly related to levamisole was asymptomatic moderate neutropenia, which was reversible spontaneously or after treatment discontinuation. Thus, in children with SSINS and frequent relapses, levamisole prolonged the time to relapse and also prevented recurrence during one year of treatment compared to prednisone alone. However, regular blood controls are necessary for safety issues. Levamisole has been considered the least toxic and least expensive steroid-sparing drug for preventing relapses of steroid-sensitive idiopathic nephrotic syndrome (SSINS). However, evidence for this is limited as previous randomized clinical trials were found to have methodological limitations. Therefore, we conducted an international multicenter, placebo-controlled, double-blind, randomized clinical trial to reassess its usefulness in prevention of relapses in children with SSINS. The efficacy and safety of one year of levamisole treatment in children with SSINS and frequent relapses were evaluated. The primary analysis cohort consisted of 99 patients from 6 countries. Between 100 days and 12 months after the start of study medication, the time to relapse (primary endpoint) was significantly increased in the levamisole compared to the placebo group (hazard ratio 0.22 [95% confidence interval 0.11–0.43]). Significantly, after 12 months of treatment, six percent of placebo patients versus 26 percent of levamisole patients were still in remission. During this period, the most frequent serious adverse event (four of 50 patients) possibly related to levamisole was asymptomatic moderate neutropenia, which was reversible spontaneously or after treatment discontinuation. Thus, in children with SSINS and frequent relapses, levamisole prolonged the time to relapse and also prevented recurrence during one year of treatment compared to prednisone alone. However, regular blood controls are necessary for safety issues. Idiopathic nephrotic syndrome (INS) is a rare disease with an incidence that varies between 2 and 7 cases per 100,000 children per year.1The primary nephrotic syndrome in childrenIdentification of patients with minimal change nephrotic syndrome from initial response to prednisone. A report of the International Study of Kidney Disease in Children.J Pediatr. 1981; 98: 561-564Abstract Full Text PDF PubMed Scopus (631) Google Scholar, 2El Bakkali L. Rodrigues Pereira R. Kuik D.J. et al.Nephrotic syndrome in the Netherlands: a population-based cohort study and a review of the literature.Pediatr Nephrol. 2011; 26: 1241-1246Crossref PubMed Scopus (72) Google Scholar It is hypothesized that INS results from a defect in lymphocyte function.3Davin J.C. The glomerular permeability factors in idiopathic nephrotic syndrome.Pediatr Nephrol. 2016; 31: 207-215Crossref PubMed Scopus (54) Google Scholar Most children with INS are steroid sensitive. Seventy percent of the latter also experience ≥1 relapses.1The primary nephrotic syndrome in childrenIdentification of patients with minimal change nephrotic syndrome from initial response to prednisone. A report of the International Study of Kidney Disease in Children.J Pediatr. 1981; 98: 561-564Abstract Full Text PDF PubMed Scopus (631) Google Scholar, 2El Bakkali L. Rodrigues Pereira R. Kuik D.J. et al.Nephrotic syndrome in the Netherlands: a population-based cohort study and a review of the literature.Pediatr Nephrol. 2011; 26: 1241-1246Crossref PubMed Scopus (72) Google Scholar Half of these children relapse frequently after cessation of corticosteroids (frequently relapsing nephrotic syndrome [FRNS]) or become steroid dependent.4ISKDC 1982 anonymousNephrotic syndrome in children: a randomized trial comparing two prednisone regimens in steroid- responsive patients who relapse early. Report of the International Study of Kidney Disease in Children.J Pediatr. 1982; 95: 229-243Google Scholar Children with FRNS are then exposed to the side effects of steroids.1The primary nephrotic syndrome in childrenIdentification of patients with minimal change nephrotic syndrome from initial response to prednisone. A report of the International Study of Kidney Disease in Children.J Pediatr. 1981; 98: 561-564Abstract Full Text PDF PubMed Scopus (631) Google Scholar, 2El Bakkali L. Rodrigues Pereira R. Kuik D.J. et al.Nephrotic syndrome in the Netherlands: a population-based cohort study and a review of the literature.Pediatr Nephrol. 2011; 26: 1241-1246Crossref PubMed Scopus (72) Google Scholar To reduce the relapse rate, several drugs have been used.1The primary nephrotic syndrome in childrenIdentification of patients with minimal change nephrotic syndrome from initial response to prednisone. A report of the International Study of Kidney Disease in Children.J Pediatr. 1981; 98: 561-564Abstract Full Text PDF PubMed Scopus (631) Google Scholar, 2El Bakkali L. Rodrigues Pereira R. Kuik D.J. et al.Nephrotic syndrome in the Netherlands: a population-based cohort study and a review of the literature.Pediatr Nephrol. 2011; 26: 1241-1246Crossref PubMed Scopus (72) Google Scholar Among these, levamisole was considered the least toxic and least expensive and the only one not classified as an immunosuppressive agent until the pharmaceutical industry withdrew it from the market in 2004 for human use due to lack of clear indications.5Davin J.C. Merkus M. Levamisole in steroid- sensitive nephrotic syndrome of childhood: the lost paradise?.Pediatr Nephrol. 2005; 20: 10-14Crossref PubMed Scopus (38) Google Scholar Evidence of the efficacy of levamisole in FRNS was restricted to retrospective studies and a few clinical trials, all of which had some methodological limitations.6Levamisole for corticosteroid dependent nephrotic syndrome in childhoodBritish Association for Paediatric Nephrology.Lancet. 1991; 337: 1555-1557PubMed Google Scholar, 7Rashid H.U. Ahmed S. Fatima N. et al.Levamisole in the treatment of steroid dependent or frequent relapsing nephrotic syndrome in children.Bangladesh Ren J. 1996; 15: 6-8Google Scholar, 8Dayal U. Dayal A.K. Shastry J.C.M. et al.Use of levamisole in maintaining remission in steroid sensitive nephrotic syndrome.Nephron. 1994; 66: 408-412Crossref PubMed Scopus (57) Google Scholar Since then, it has only remained available as a low-cost drug for veterinary use, given of its anthelminthic properties. We hypothesized that the addition of levamisole following complete remission with steroid therapy in children with FRNS or steroid dependency would either prevent relapses or prolong the time to relapse during a 1-year treatment period. For this reason, we conducted an international, multicenter, double-blind, placebo-controlled, randomized clinical trial (RCT) to assess the efficacy and safety of 1-year levamisole treatment in children with FRNS. Study medication (levamisole or placebo) started during prednisone treatment for a relapse. To study longer term efficacy and safety of levamisole, patients still in remission and on levamisole treatment at trial completion were evaluated in an additional longer term follow-up. Between October 2007 and March 2012, 103 patients, recruited from 13 sites in 6 countries (The Netherlands, Belgium, France, Italy, Poland, and India), were randomized. Ninety-nine patients were included in the modified intention-to-treat population. Three randomized patients could not be included because they did not start the study medication; for 2 of them, the study medication (placebo) did not arrive on time, and proteinuria developed in the third patient (levamisole) before the start of study medication. One patient (placebo) was excluded due to missing primary outcome information. Eight patients prematurely discontinued study medication (4 levamisole and 4 placebo) and were censored. No patients were lost to follow-up (Figure 1). Nonadherence with study treatment was not detected in any patient. Demographic and baseline characteristics were similar across both study treatment groups (Table 1). Analysis of age and steroid dependency (SD) by region showed a similar age distribution for both regions, but a difference in the distribution of SD between Europe and India (Table 2). The range and distribution of the lowest prednisone doses necessary to prevent a relapse before the start of study are depicted in the Supplementary Material Table S1.Table 1Baseline characteristics of the modified intention-to-treat populationBaseline characteristicsPlacebo (N = 49)Levamisole (N = 50)Cyclophosphamide, N (%)aPrevious cyclophosphamide treatment.3 (6)3 (6)Steroid-dependence, N (%)32 (65)36 (72) Lowest prednisone, mean (SD)bLowest mean prednisone dose necessary to prevent a relapse before inclusion in the randomized clinical trial.21.16 (12.73) mg/m2/AD26.33 (16.42) mg/m2/ADRegion, N (%) France4 (8)5 (10) Rest of Europe24 (49)23 (46) India21 (43)22 (44)Sex, boys, N (%)34 (69)36 (72)Ethnicity, N (%) Caucasian25 (51)25 (50) Black2 (4)0 (0) Asian21 (43)23 (46) Other1 (2)1 (2) Missing0 (0)1 (2)Age at presentation of NS (yr), median (IQR)3.5 (2.25–5.75)4 (2–5.25)Age at randomization (yr), mean (SD)6.0 (3.1)5.7 (2.6)Duration disease (yr),cAge at presentation of newly diagnosed nephrotic syndrome. median (IQR)1 (0–2)1 (0–2)AD, alternate day; IQR, interquartile range; NS, nephrotic syndrome.a Previous cyclophosphamide treatment.b Lowest mean prednisone dose necessary to prevent a relapse before inclusion in the randomized clinical trial.c Age at presentation of newly diagnosed nephrotic syndrome. Open table in a new tab Table 2Age and steroid dependence distribution in the European and Indian subgroups of the modified intention-to-treat populationAge/steroid dependenceEuropean countries (N = 56)India (N = 43)Age, yr,aχ2 test, P = 0.29. 2–524 (43%)23 (54%) 6–1632 (57%)20 (47%)Steroid dependencebχ2 test, P < 0.0001. Yes50 (89%)18 (42%) No6 (11%)25 (58%)a χ2 test, P = 0.29.b χ2 test, P < 0.0001. Open table in a new tab AD, alternate day; IQR, interquartile range; NS, nephrotic syndrome. Kaplan-Meier analysis in the primary analysis (modified intention-to-treat) population showed similar cumulative relapse-free survival probabilities for both treatment groups during the first 100 days of study medication (Figure 2). However, afterward, a difference in the time to relapse became apparent in both treatment groups in favor of the levamisole group (log-rank analysis, total period, P = 0.015). By the end of the 1-year study period, 6% of placebo (3/49) versus 26% (13/50) of levamisole patients were still in remission and on study medication (Figure 2). Since Kaplan-Meier curves showed that proportional hazards could not be assumed throughout the 1-year study period, a time-dependent Cox proportional hazards regression analysis was performed incorporating the stratification factors. During the first 100 days of study medication similar hazards for a relapse needing prednisone were observed in both treatment groups (hazard ratio [HR]: 1.14, 95% confidence interval [CI] 0.56–2.34, P = 0.72). Afterward, a significantly lower hazard was observed in the levamisole group compared with the placebo group (HR: 0.22, 95% CI 0.11–0.43, P = 0.001) (Table 3). The HR was not confounded by the prespecified covariates of sex, age, and ethnicity. Exploratory subgroup analyses suggested insufficient evidence of treatment effect modification of the time to relapse by region (India vs. Europe), SD (yes vs. no), sex, and age (2–5 years vs. ≥6 years) (formal tests for treatment by subgroup interaction; P values of 0.79, 0,64, 0.35, and 0.51, respectively); see Kaplan-Meier curves for region and SD/FR in the Supplementary Material Figures S1 and S2.Table 3Time to relapse (primary outcome) in the mITT population: results of the time-dependent Cox proportional hazards regression modelLevamisole (N = 50)Placebo (N = 49)Levamisole vs. placebo, hazard ratio (95% CI)aHazard ratios were calculated using a time-dependent Cox proportional hazards regression model with corresponding 95% confidence intervals. The hazard ratio can be interpreted as the relative risk of the outcome at any fixed point in time.P valueNo. of patients with a relapse needing prednisone <100 days of follow-up1614Crude: 1.19 (0.58–2.43)0.64AdjustedbAdjusted for the stratification factors.: 1.14 (0.56–2.34)0.72 ≥100 days of follow-up1728Crude: 0.34 (0.18–0.63)0.001AdjustedbAdjusted for the stratification factors.: 0.22 (0.11–0.43)<0.001CI, confidence interval; mITT, modified intention-to-treat.a Hazard ratios were calculated using a time-dependent Cox proportional hazards regression model with corresponding 95% confidence intervals. The hazard ratio can be interpreted as the relative risk of the outcome at any fixed point in time.b Adjusted for the stratification factors. Open table in a new tab CI, confidence interval; mITT, modified intention-to-treat. At 1-year follow-up, a lower cumulative proportion of patients with a relapse requiring prednisone was seen in the levamisole group (33/50, 66%) compared with the placebo group (42/49, 86%) (relative risk estimate/crude relative risk, 0.77; 95% CI 0.61–0.97; after adjustment for the stratification variables, adjusted odds ratio was 0.30; 95% CI 0.11–0.82, P = 0.02). Formal evaluation of effect modification using treatment by subgroup interaction terms in multivariable regression models, including the stratification variables, suggested insufficient evidence of heterogeneity of treatment effect between these subgroups (Supplementary Material Table S2). In the safety population, more patients with at least 1 adverse event (AE) were seen in the levamisole group versus the placebo group (levamisole, 58% [29/50] vs. placebo, 38% [19/50], p = 0.045). However, the most clinically prominent AEs were similar in both groups (pyrexia, nasopharyngitis, cough, and mild neutropenia; 1000–1500 cells/μl in 3 patients of each group). None of the latter required study discontinuation (Table 4). Ten nonlethal serious AE occurred. They included 5 cases of moderate neutropenia (500–1000 cells/μl) (levamisole, 4/50 vs. placebo, 1/50) that were asymptomatic and reversible after levamisole discontinuation (2/4 levamisole group) or spontaneously (2/4 levamisole group); 3 hospitalizations (levamisole, 3/50 vs. placebo, 0/50), not related with neutropenia; 2 levamisole patients presented with reversible side effects after medication discontinuation, 1 with a reduced glomerular filtration rate and 1 with arthritis and antineutrophil cytoplasmic antibodies. With regard to the 4 levamisole patients with moderate neutropenia, in 2 of them, neutropenia resolved without terminating levamisole and both reached normal completion of the trial. The other 2 levamisole patients with neutropenia presented with a relapse at the same time, so their primary endpoint was reached and study medication was terminated. With respect to the 3 levamisole patients who required hospitalization (for high fever in 1, pulmonary infection in 1, and abdominal pain in 1), 2 presented with relapse at the same time, so trial medication was discontinued, whereas the third patient did not end trial medication but relapsed 8 months later (Table 4).Table 4Most frequently encountered SAEs in the safety populationLevamisole (n/N)Placebo (n/N)AEs At least 1 AEaPulmonary infection, fever, abdominal pain.29/5019/50 Cough6/506/50 Nasopharyngitis8/5010/50 Pyrexia10/506/50 Neutropenia (1000–1500/μl)3/503/50SAEs Neutropenia (500–1000/μl)4/501/50 Neutropenia (<500/μl)1/50HospitalizationbP = 0.0453/50aPulmonary infection, fever, abdominal pain.0/50Reduced GFR1/500/50Arthritis/ANCA+1/500/50AEs, adverse events; ANCA, antineutrophil cytoplasmic antibody; GFR, glomerular filtration rate; SAEs, serious adverse events.a Pulmonary infection, fever, abdominal pain.b P = 0.045 Open table in a new tab AEs, adverse events; ANCA, antineutrophil cytoplasmic antibody; GFR, glomerular filtration rate; SAEs, serious adverse events. Comparison of laboratory values per visit (hemoglobin, platelets, neutrophils, albumin, aspartate aminotransferase, and glomerular filtration rate), categorized as high, low, or normal according to age, did not show any significant difference between the 2 treatment groups except at visit 3. At that time, a significantly higher number of low glomerular filtration rate values could be observed for the levamisole group (P = 0.03). The normal and abnormal values for the glomerular filtration rate, neutrophils, and aspartate aminotransferase according to time are shown in the Supplementary Material Figures S3–S5. No difference in delta height between baseline and 1-year follow-up was observed between the levamisole and placebo groups (Supplementary Material Figure S6). Of the 13 levamisole patients who did not present with a relapse during the year of the RCT, only 5 could subsequently be included in the longer term follow-up extension of the trial (Figure 1). Regarding the other 8 patients, all Indian, Indian legislation did not allow import of study medication after completion of the trial period because local Indian companies have been producing levamisole for almost 3 decades. Of the 5 included patients, 1 had a relapse after 2 months and 1 stopped study participation after only 4 months (reason unknown). The 3 remaining patients were treated with levamisole for 12 months in the longer term follow-up without a relapse; of those, only 1 was followed for 6 months after levamisole cessation and did not relapse. One serious AE was reported: asymptomatic neutropenia, <500 cells/μl, which resolved after levamisole termination. This study shows that the addition of levamisole to standard steroid therapy in children with FRNS increased the time to relapse, after termination of prednisone treatment (100 days post-randomization). Furthermore, it allowed 26% of levamisole patients to be free of relapse for at least 1 year (vs. 6% in the placebo group). These results confirm the efficacy of levamisole in FRNS, suggested previously by several retrospective studies and 3 RCTs that had methodological limitations to some extent.6Levamisole for corticosteroid dependent nephrotic syndrome in childhoodBritish Association for Paediatric Nephrology.Lancet. 1991; 337: 1555-1557PubMed Google Scholar, 7Rashid H.U. Ahmed S. Fatima N. et al.Levamisole in the treatment of steroid dependent or frequent relapsing nephrotic syndrome in children.Bangladesh Ren J. 1996; 15: 6-8Google Scholar, 8Dayal U. Dayal A.K. Shastry J.C.M. et al.Use of levamisole in maintaining remission in steroid sensitive nephrotic syndrome.Nephron. 1994; 66: 408-412Crossref PubMed Scopus (57) Google Scholar Two RCTs7Rashid H.U. Ahmed S. Fatima N. et al.Levamisole in the treatment of steroid dependent or frequent relapsing nephrotic syndrome in children.Bangladesh Ren J. 1996; 15: 6-8Google Scholar, 8Dayal U. Dayal A.K. Shastry J.C.M. et al.Use of levamisole in maintaining remission in steroid sensitive nephrotic syndrome.Nephron. 1994; 66: 408-412Crossref PubMed Scopus (57) Google Scholar had unclear allocation concealment, no blinding of patients and investigators, insufficient statistical power, and inadequate relapse definitions (i.e., not defined as a relapse necessitating prednisone treatment). The British Association of Pediatric Nephrology (BAPN) trial6Levamisole for corticosteroid dependent nephrotic syndrome in childhoodBritish Association for Paediatric Nephrology.Lancet. 1991; 337: 1555-1557PubMed Google Scholar had adequate allocation concealment and was double-blinded and placebo-controlled; however, levamisole was given for only 4 months. In this study, more than half of the patients had received cyclophosphamide, which might have biased the evaluation of levamisole effect because it has been suggested that levamisole may be more effective in patients previously treated with alkylating therapy.9Abeyagunawardena A.S. Dillon M.J. Rees L. et al.The use of steroid-sparing agents in steroid-sensitive nephrotic syndrome.Pediatr Nephrol. 2003; 18: 919-924Crossref PubMed Scopus (41) Google Scholar In the latter trial, a difference in efficacy between the levamisole and the placebo groups became apparent after 40 days, in contrast to our trial in which a beneficial effect appeared after 100 days. The difference in efficacy between the BAPN and our trial could be the result of a greater dosage and longer steroid treatment in our study (cumulative prednisone dosage, alternate days: BAPN trial, 24.5 mg/kg during 10 weeks vs. levamisole trial, 2000 mg/m2 during 16 weeks). This is illustrated by a higher percentage of control patients in remission at 100 days in our study compared with the BAPN study (percentage of control subjects in remission on day 100 in the levamisole trial was 70% vs. BAPN, <20%). The currently observed increased efficacy of levamisole after day 100 that coincided with the cessation of prednisone might result from an increased metabolism and decreased bioavailability of levamisole due to steroids as has been shown for cyclosporine, tacrolimus, and sirolimus.10Konishi H. Sumi M. Shibata N. et al.Decrease in oral bioavailability of ciclosporin by intravenous pulse of methylprednisolone succinate in rats.J Pharm Pharmacol. 2004; 56: 1259-1266Crossref PubMed Scopus (12) Google Scholar Although levamisole is not classified as an immunosuppressive agent, investigation of possible metabolic and transporter pathways with prednisone and duration of prednisone treatment, regarding concentration levels, has not yet been investigated. Exploratory descriptive analyses in separate subgroups suggested possible differential treatment effects for subgroups of the region and steroid dependency (Supplementary Material Figures S1 and S2 and Table S2). However, formal evaluation of effect modification using treatment-by-subgroup interaction terms in multivariable regression models, including stratification variables, suggested insufficient evidence of heterogeneity of treatment effect between these subgroups. Looking at the distribution of SD patients in the European subgroup compared with the Indian subgroup, the greater majority of the European group (89%) involved SD patients, whereas in the Indian subgroup, a proportion of 42% involved SD patients. This may have resulted in confounding, which is obscured in the descriptive within-subgroups analyses. Moreover, these subgroup analyses should be interpreted with much caution as these are hampered by a lack of statistical power to adequately analyze differential treatment effects between subgroups. This RCT was only sufficiently powered to assess the overall treatment effect. Additionally, the issue of multiplicity of testing, which increases the probability of false-positive findings, related to subgroup analyses should be acknowledged. Therefore, the results of the exploratory subgroup analyses should only be considered as a hypothesis-generating exercise, needing establishment by future adequately powered RCTs. So far, earlier RCTs on levamisole only included SD patients6Levamisole for corticosteroid dependent nephrotic syndrome in childhoodBritish Association for Paediatric Nephrology.Lancet. 1991; 337: 1555-1557PubMed Google Scholar or did not report the results of SD and frequently relapsing patients separately.7Rashid H.U. Ahmed S. Fatima N. et al.Levamisole in the treatment of steroid dependent or frequent relapsing nephrotic syndrome in children.Bangladesh Ren J. 1996; 15: 6-8Google Scholar, 8Dayal U. Dayal A.K. Shastry J.C.M. et al.Use of levamisole in maintaining remission in steroid sensitive nephrotic syndrome.Nephron. 1994; 66: 408-412Crossref PubMed Scopus (57) Google Scholar The smaller proportion of included SD patients in India compared with Europe is consistent with a recent retrospective study from this country.11Dawman L. Mehta A. Sharawat I.K. Yadav R. Risk factors for steroid dependency in children with idiopathic nephrotic syndrome in India.Indian J Pediatr. 2016; 83: 261Crossref PubMed Scopus (5) Google Scholar It might be explained by genetic predisposition and/or environmental factors.12Sharples P.M. Poulton J. White R.H.R. Steroid responsive nephrotic syndrome is more common in Asians.Arch Dis Child. 1985; 60: 1014-1017Crossref PubMed Scopus (88) Google Scholar, 13McKinney P.A. Feltbowe R.G. Brocklebank J.T. et al.Time trends and ethnic patterns of childhood nephrotic syndrome in Yorkshire, UK.Pediatr Nephrol. 2001; 16: 1040-1044Crossref PubMed Scopus (156) Google Scholar The small proportion of frequently relapsing patients in the European group may be explained by a more frequent use of the French prednisone protocol for a relapse in Europe. In this protocol, relapse treatment includes 4 months of steroids on alternate days in addition to the period of daily treatment until remission. Following this protocol, it is practically impossible to fit with the definition of frequently relapsing that requires at least 4 relapses per year, even if the protocol is adapted individually. In the safety population, asymptomatic and reversible neutropenia was reported in 4 placebo patients (4/50, 8%) and in 7 levamisole patients (7/50, 14%) (3 mild and 4 moderate cases) during the RCT year as well as in 1 patient (severe) in the longer term follow-up phase. All patients were asymptomatic and reversible after discontinuation of the drug or spontaneously in 2 patients. Although complete blood counts were obtained every 2 to 4 weeks6Levamisole for corticosteroid dependent nephrotic syndrome in childhoodBritish Association for Paediatric Nephrology.Lancet. 1991; 337: 1555-1557PubMed Google Scholar, 7Rashid H.U. Ahmed S. Fatima N. et al.Levamisole in the treatment of steroid dependent or frequent relapsing nephrotic syndrome in children.Bangladesh Ren J. 1996; 15: 6-8Google Scholar or 3 times a month,8Dayal U. Dayal A.K. Shastry J.C.M. et al.Use of levamisole in maintaining remission in steroid sensitive nephrotic syndrome.Nephron. 1994; 66: 408-412Crossref PubMed Scopus (57) Google Scholar neutropenia was not reported in 3 other RCTs.6Levamisole for corticosteroid dependent nephrotic syndrome in childhoodBritish Association for Paediatric Nephrology.Lancet. 1991; 337: 1555-1557PubMed Google Scholar, 7Rashid H.U. Ahmed S. Fatima N. et al.Levamisole in the treatment of steroid dependent or frequent relapsing nephrotic syndrome in children.Bangladesh Ren J. 1996; 15: 6-8Google Scholar, 8Dayal U. Dayal A.K. Shastry J.C.M. et al.Use of levamisole in maintaining remission in steroid sensitive nephrotic syndrome.Nephron. 1994; 66: 408-412Crossref PubMed Scopus (57) Google Scholar In 7 cohort studies (2 RCTs and 5 cohort studies), largely from Middle East countries and India, neutropenia was only reported in 8 of a total of 573 included patients in these studies.14Al-Saran K. Mirza K. Al-Ghanam G. et al.Experience with levamisole in frequently relapsing, steroid-dependent nephrotic syndrome.Pediatr Nephrol. 2006; 21: 201-205Crossref PubMed Scopus (38) Google Scholar, 15Ekambaram S. Mahalingam V. Nageswaran P. et al.Efficacy of Levamisole in Children with Frequently Relapsing and Steroid-dependent Nephrotic Syndrome.Indian Pediatr. 2014; 51: 371-373Crossref PubMed Scopus (17) Google Scholar, 16Elmas A.T. Tabel Y. Elmas O.N. Long- and short-term efficacy of levamisole in children with steroid- sensitive nephrotic syndrome.Int Urol Nephrol. 2013; 45: 1047-1055Crossref PubMed Scopus (13) Google Scholar, 17Madani A. Isfahani S.T. Rahimzadeh N. et al.Effect of levamisole in steroid-dependent nephrotic syndrome.Iran J Kidney Dis. 2010; 4: 292-296PubMed Google Scholar, 18Al-Ibrahim A.A. Al-Kharraz S.M. Al-Sadoon D.M. et al.Levamisole Therapy as a Second-line Immunosuppressive Agent in Corticosteroid-sensitive Nephrotic Syndrome in Children.Saudi J Kidney Dis Transplant. 2003; 14: 153-157PubMed Google Scholar, 19Bagga A. Sharma A. Srivastava R.N. Levamisole therapy in corticosteroid-dependent nephrotic syndrome.Pediatr Nephrol. 1997; 11: 415-417Crossref PubMed Scopus (61) Google Scholar, 20Sumegi V. Haszon I. Ivanyi B. et al.Long-term effects of levamisole treatment in childhood nephrotic syndrome.Pediatr Nephrol. 2004; 19: 1354-1360Crossref PubMed Scopus (29) Google Scholar Most of these studies checked the blood counts on a regular basis (biweekly or monthly), but Dayal et al.8Dayal U. Dayal A.K. Shastry J.C.M. et al.Use of levamisole in maintaining remission in steroid sensitive nephrotic syndrome.Nephron. 1994; 66: 408-412Crossref PubMed Scopus (57) Google Scholar and Ekambaram et al.15Ekambaram S. Mahalingam V. Nageswaran P. et al.Efficacy of Levam