Vivarelli M, Colucci M, Gargiulo A, et al. - Good tolerability of belimumab (B-cell-modulating agent) was evident when administered for short-term to pediatric frequently relapsing nephrotic syndrome (FRNS) patients, however, no inferences were reached regarding efficacy, and clear improvements were not seen.

• An open-label, prospective, single-arm pilot study of i.v. belimumab for 12 months to treat pediatric FRNS.

• Potential benefits of belimumab were counterbalanced by the inconvenience of monthly in-hospital i.v. infusions.

• A pathogenic role of circulating memory B cells in pediatric FRNS is supported.

• Of 5 patients included, four reached the primary 6-month endpoint.

• Of those, two completed the 12-month endpoint.

• No significant reduction in the mean number of relapses and the mean cumulative prednisone dose was observed during the 6 months on belimumab vs the 6 months before belimumab therapy.