FDA Approves First Drug for Relapsing Nephrotic Syndrome

Gazyva (obinutuzumab)What to know

30-second read

For Nephrology · Pediatrics

Who

Patients 2 years and older with frequently relapsing or steroid-dependent, childhood-onset idiopathic nephrotic syndrome, in complete remission.

What’s new

First FDA-approved drug for the disease. Every current regimen — steroids, calcineurin inhibitors, rituximab — has been prescribed off-label until now.

Evidence

INSHORE (85 patients, ages 2–25): sustained complete remission at week 52 in 95.5% vs. 73.2% on mycophenolate mofetil (adjusted diff. 23.4 points, p=0.0031).

Big advantage

A type II anti-CD20 antibody with stronger B-cell cytotoxicity than rituximab in vitro; small case reports already use it off-label after rituximab fails or isn’t tolerated.

Key consideration

Boxed warnings for hepatitis B reactivation and PML, shared with rituximab; more grade ≥3 adverse events than MMF (25.0% vs. 7.3%), the trial's comparator, not rituximab.

Availability

Approved 25 September 2026. Rituximab (off-label) and MMF remain available; combined or list pricing for this indication is not yet public.

Practice impactIf rituximab fails or is not tolerated

The randomized evidence supports obinutuzumab broadly, not specifically as a rituximab successor. A child stable on off-label rituximab has no trial evidence to switch; the clearer case is a child who has already cycled through it without success.

Read the full physician analysis

Full analysis · 7 min readFDA approval notice · INSHORE trial (WCN 2026) · Gazyva prescribing information

FDA approved obinutuzumab (Gazyva, Genentech) on 25 September 2026 for patients 2 years and older with frequently relapsing or steroid-dependent, childhood-onset idiopathic nephrotic syndrome — the first drug ever specifically approved for the disease. Every regimen used before now, including the anti-CD20 antibody rituximab already familiar to most pediatric nephrologists, has been prescribed off-label. What a nephrologist actually gains is narrower than "a new drug": a second antibody targeting the same B cells, with its own randomized trial, its own boxed warnings, and an unresolved question this approval doesn't settle — where does it sit next to the off-label option already working for many children?

A Second Anti-CD20 Antibody, Not the First

Rituximab has been the de facto anti-CD20 option in relapsing and steroid-dependent nephrotic syndrome for years, prescribed off-label on the strength of institutional experience rather than a disease-specific label. Obinutuzumab and rituximab both deplete CD20-positive B cells, the population thought to drive relapse, but they are not the same molecule. Rituximab is a chimeric, type I anti-CD20 antibody; obinutuzumab is a humanized, type II antibody engineered for stronger direct, non-apoptotic cytotoxicity against B cells, with more potent depletion shown in vitro. That mechanistic difference is the rationale, documented in a small but real off-label literature, for reaching for obinutuzumab specifically in children who do not respond to rituximab or cannot tolerate it — a published case report describes a successful switch to obinutuzumab in a rituximab-intolerant child with difficult-to-treat disease, and a handful of similar reports exist elsewhere. It is a thin evidence base — by one count, only three publications describe obinutuzumab used off-label in children with nephrotic syndrome — but it is the evidence a nephrologist actually has for positioning the new drug against the old one, since the trial that won this approval did not test that question.

What INSHORE Actually Tested

INSHORE, a Phase 3, randomized, open-label, multicenter trial, enrolled 85 patients ages 2 to 25 with childhood-onset, frequently relapsing or steroid-dependent nephrotic syndrome, in remission at enrollment. It randomized them 1:1 to intravenous obinutuzumab, dosed on Day 1 and Day 15 and again at Weeks 24 and 26, against daily oral mycophenolate mofetil (MMF) — an active comparator, not rituximab. The primary endpoint, sustained complete remission at week 52, favored obinutuzumab decisively: 95.5% against 73.2% on MMF, an adjusted difference of 23.4 percentage points (95% CI 6.85–38.90; p=0.0031). Key secondary endpoints also favored obinutuzumab, including relapse-free survival and reduced glucocorticoid exposure during the study — a steroid-sparing effect that matters given how much of the disease's long-term burden, growth suppression and bone loss among them, comes from repeated steroid courses rather than the kidney disease itself. The results were presented as a late-breaking abstract at the International Society of Nephrology's 2026 World Congress of Nephrology. What they are not is a comparison against rituximab. FDA's approval rests on evidence that obinutuzumab beats MMF; it says nothing about whether it beats, matches or trails the anti-CD20 antibody most nephrologists already reach for first.

Three anti-relapse options next to each other

	Gazyva (obinutuzumab)	Mycophenolate mofetil	Rituximab (off-label)
FDA-approved for this disease	Yes — 25 September 2026	No (used off-label)	No (used off-label)
Anti-CD20 mechanism	Type II, humanized	N/A — antimetabolite	Type I, chimeric
Trial evidence in this disease	INSHORE: 95.5% sustained remission at week 52	INSHORE comparator arm: 73.2%	No randomized trial; case series and registries only
Reported role after rituximab fails	Used off-label in small case reports after rituximab failure or intolerance	Not typically used for this purpose	The first-line off-label choice; some children develop resistance or intolerance
Boxed warnings	Hepatitis B reactivation, PML	None	Hepatitis B reactivation, PML (same drug class)

INSHORE tested obinutuzumab against MMF, not against rituximab. No randomized trial has compared the two antibodies head-to-head in this disease; NCT07233330, testing obinutuzumab in adults with rituximab-dependent nephrotic syndrome, is still enrolling.

Two Boxed Warnings, Now on a Label a Nephrologist Will Actually Read

Obinutuzumab's label carries boxed warnings for hepatitis B virus reactivation, which in some cases has led to fulminant hepatitis, hepatic failure and death, and for progressive multifocal leukoencephalopathy, the JC virus infection that can follow prolonged B-cell depletion. Neither warning is new to this drug class — rituximab carries the same two boxed warnings, for the same reason — but until now, a pediatric nephrologist using an anti-CD20 antibody in this disease was applying warnings written for a hematology-oncology label by extension. Obinutuzumab's label is the first written with this specific pediatric population and disease in view. Practically, that means screening every candidate for HBV infection before the first infusion, whether or not they've had rituximab before, and monitoring HBV-positive patients through and after treatment. Infusion-related reactions require premedication; in INSHORE, adverse events of any kind were more common on obinutuzumab than MMF (95.5% vs. 82.9%), and grade 3 or higher events ran more than three times as high (25.0% vs. 7.3%) — a comparison against the trial's own comparator, again, not against rituximab, which a practice already using it has presumably weighed and accepted for the same disease.

• Screen for hepatitis B before the first infusion, regardless of prior rituximab exposure, and monitor HBV-positive patients through and after treatment — a boxed warning now specific to this label, not one to assume was already covered.
• Don't read INSHORE as a rituximab comparison. The trial beat mycophenolate mofetil, not rituximab; nothing in the approval says obinutuzumab outperforms, matches or trails the antibody already in use.
• The clearer case for switching is rituximab resistance or intolerance, supported by mechanism and a handful of case reports — not a large or randomized evidence base, and worth naming as such to a family weighing the option.
• Confirm coverage before committing. Combined pricing and payer policy for this specific indication are not yet public, and a dedicated trial in rituximab-dependent patients (NCT07233330) is still enrolling, not reporting.

Frequently asked questions

What did FDA approve, and how is Gazyva different from rituximab?

On 25 September 2026, FDA approved obinutuzumab (Gazyva, Genentech) to reduce relapse risk in patients 2 years and older with frequently relapsing or steroid-dependent, childhood-onset idiopathic nephrotic syndrome (INS) in complete remission — the first FDA-approved drug for the disease. Both obinutuzumab and rituximab are anti-CD20 monoclonal antibodies that deplete the B cells thought to drive relapse, but they are different molecules: rituximab is a chimeric type I antibody, obinutuzumab a humanized type II antibody engineered for stronger direct B-cell cytotoxicity. Rituximab has been used off-label in INS for years; obinutuzumab now has a randomized trial and a label specific to this disease.

What did the INSHORE trial show, and did it compare Gazyva against rituximab?

No — INSHORE compared obinutuzumab against mycophenolate mofetil (MMF), not rituximab. In 85 patients ages 2 to 25, sustained complete remission at week 52 was 95.5% on obinutuzumab versus 73.2% on MMF (adjusted difference 23.4 points, 95% CI 6.85–38.90, p=0.0031), with secondary endpoints favoring obinutuzumab on relapse-free survival and reduced glucocorticoid exposure. The trial, presented at the International Society of Nephrology's 2026 World Congress, says nothing about how obinutuzumab performs against rituximab head-to-head.

What evidence exists for using Gazyva after rituximab fails or isn't tolerated?

Thin, but real. A published case report describes a successful switch to obinutuzumab in a rituximab-intolerant child with difficult-to-treat INS, and a small literature of similar off-label reports exists — by one count, only three publications on obinutuzumab in children with nephrotic syndrome. A separate, ongoing trial (NCT07233330) is testing obinutuzumab specifically in adults with rituximab-dependent nephrotic syndrome, but has not reported results. This is a rationale grounded in mechanism and case experience, not a proven, on-label answer.

What extra safety monitoring does Gazyva require?

Obinutuzumab carries boxed warnings for hepatitis B virus reactivation and progressive multifocal leukoencephalopathy (PML), shared with rituximab as a class effect of CD20-directed antibodies — screen for HBV before starting and monitor during and after treatment. Infusion-related reactions require premedication. In INSHORE, more patients had a grade 3 or higher adverse event on obinutuzumab than on MMF (25.0% vs. 7.3%) — a comparison against the trial's comparator, not against rituximab, which carries the same boxed warnings already.