Rituximab treatment for difficult-to-treat nephrotic syndrome in children: a multicenter, retrospective study

Authors: MEHMET TAŞDEMİR, NUR CANPOLAT, NURDAN YILDIZ, GÜL ÖZÇELİK, MERYEM BENZER, SEHA KAMİL SAYGILI, EMİNE NEŞE ÖZKAYIN, ÖZDE NİSA TÜRKKAN, AYŞE BALAT, CENGİZ CANDAN, MEHTAP ÇELAKIL, SEVGİ YAVUZ, NURVER AKINCI, NİLÜFER GÖKNAR, CİHANGİR AKGÜN, SEBAHAT TÜLPAR, HARİKA ALPAY, FATMA LALE SEVER, İLMAY BİLGE

Abstract: Background/aim: This study aimed to evaluate the efficacy of rituximab in children with difficult-to-treat nephrotic syndrome, considering the type of disease (steroid-sensitive or -resistant) and the dosing regimen. Materials and methods: This multicenter retrospective study enrolled children with difficult-to-treat nephrotic syndrome on rituximab treatment from 13 centers. The patients were classified based on low (single dose of 375 mg/m2 ) or high (2-4 doses of 375 mg/m2 ) initial dose of rituximab and the steroid response. Clinical outcomes were compared. Results: Data from 42 children [20 steroid-sensitive (frequent relapsing / steroid-dependent) and 22 steroid-resistant nephrotic syndrome, aged 1.9-17.3 years] were analyzed. Eleven patients with steroid-sensitive nephrotic syndrome (55%) had a relapse following initial rituximab therapy, with the mean time to first relapse of 8.4 ± 5.2 months. Complete remission was achieved in 41% and 36% of steroid-resistant patients, with the median remission time of 3.65 months. At Year 2, eight patients in steroid-sensitive group (40%) and four in steroid-resistant group (18%) were drug-free. Total cumulative doses of rituximab were higher in steroid-resistant group (p = 001). Relapse rates and time to first relapse in steroid-sensitive group or remission rates in steroid-resistant group did not differ between the low and high initial dose groups. Conclusion: The current study reveals that rituximab therapy may provide a lower relapse rate and prolonged relapse-free survival in the steroid-sensitive group, increased remission rates in the steroid-resistant group, and a significant number of drug-free patients in both groups. The optimal regimen for initial treatment and maintenance needs to be determined.

Keywords: Frequently relapsing nephrotic syndrome, immunosuppressive agents, steroid-dependent nephrotic syndrome, steroidresistant nephrotic syndrome, remission

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