Obinutuzumab Achieves 95.5% Remission in INS, May Shift Steroid-Sparing Treatment Strategies

Idiopathic nephrotic syndrome (INS) is a rare autoimmune kidney disease without any therapeutics approved by the US Food and Drug Administration (FDA). Recently, the FDA granted priority review to Genentech’s obinutuzumab (Gazyva), adding to a January 2026 Breakthrough Therapy Designation (BTD) and expected regulatory decision in September 2026.

Data from the phase 3 INShore trial evaluating the efficacy and safety of obinutuzumab showed sustained complete remission at week 52 was achieved by 95.5% of patients treated with obinutuzumab compared with 73.2% of those receiving mycophenolate mofetil (MMF), representing an adjusted difference of 23.39% (95% CI, 6.85-38.90; P = .0031). Obinutuzumab was also associated with statistically significant and clinically meaningful improvements in key secondary endpoints, including overall relapse-free survival, median time to relapse or death, cumulative corticosteroid dose, and number of relapses.

“Not only did the primary outcome, which looked at sustained complete remission at one year, but the secondary outcomes looking at the number of relapses, what the cumulative steroid exposure was between the groups was also pretty remarkable,” Keisha Gibson, MD, MPH, a pediatric nephrologist and Division Chief of the Pediatric Nephrology Division at the UNC School of Medicine said in an interview with HCPLive. “It was very clear that the children that were randomized to the obinutuzumab arm maintained steroid-free remission without relapses far greater than those that were randomized to MMF.”

Although a rare condition, INS is the most common pediatric glomerular disease, with a meta-analysis of 27 studies reporting a mean incidence of 2.92 cases per 100,000 children annually. The condition is characterized by edema, heavy proteinuria, and hyperlipidemia. Patients can attain complete remission with corticosteroids, although relapses are common and up to 50% of children are either frequently relapsing and/or steroid-dependent.

Several steroid-sparing agents are utilized, either sequentially or in combination, to sustain disease remission or reduce the frequency of relapses. A subset of patients, however, continues to relapse and develop significant medication toxicities, such as Cushing syndrome, short stature, hypertrichosis, and nephrotoxicity. About 10–15% of patients are steroid-resistant and at risk of developing kidney failure if they do not respond to further immunosuppressive therapy.

Obinutuzumab is a CD20-directed cytolytic antibody with previous FDA approvals for the treatment of chronic lymphocytic leukemia, follicular lymphoma, and active lupus nephritis.

INShore was a randomized, open-label phase 3 trial that included 85 children and young adults 2 to 25 years of age in clinical remission with frequently relapsing or steroid-dependent nephrotic syndrome. Participants were randomly assigned 1:1 to receive intravenous obinutuzumab at weeks 0, 2, 24, and 26 or daily oral MMF. At baseline, mean age was 9.9 years (SD, 4.39) and serum albumin was 4.3 g/dL (SD, 0.42); median estimated glomerular filtration rate was 120.0 mL/min/1.73 m² (IQR, 110.0-134.0) and UPCR was 0.0 g/g (IQR, 0.0-0.1).

The safety profile of obinutuzumab was consistent with previously reported data in adults, with no new safety signals identified.

“The features of all of these medications that we use for INS are that they're immunosuppressive, and so certainly there's always a risk of infection, but with the INShore study, we really didn't see a signal for increased incidences of infection,” Gibson said. “Of course, obinutuzumab is an engineered biologic agent, and there were some infusion reactions noted with this. This is not uncommon whenever we're using biologics, especially those directed against B cells. Overall, the safety profile for this medication looks quite good and not different from what we see with mycophenolate mofetil.”

Editor’s note: Gibson reports no relevant disclosures.

References

1. Hogan P, Greenbaum LA, Nozu K, et al. B-cell–targeted therapy for idiopathic nephrotic syndrome: results of the global phase 3, multicenter INShore trial assessing obinutuzumab vs mycophenolate mofetil. Presented at: World Congress of Nephrology; 2026; Yokohama, Japan.

2. Obinutuzumab Looks Favorable for Childhood-Onset Idiopathic Nephrotic Syndrome. Renal and Urology News. Published November 10, 2025. Accessed June 25, 2026. https://www.renalandurologynews.com/news/obinutuzumab-looks-favorable-for-childhood-onset-idiopathic-nephrotic-syndrome/

3. Chan EY, Boyer O. Childhood idiopathic nephrotic syndrome: recent advancements shaping future guidelines. Pediatric Nephrology. Published online December 26, 2024. doi:https://doi.org/10.1007/s00467-024-06634-9