ANCA-Associated Vasculitis Treatment: Rituximab, Biologics, and Infusion Therapy

ANCA-associated vasculitis (AAV) is a group of rare autoimmune diseases in which the immune system attacks small blood vessels, damaging organs like the kidneys, lungs, sinuses, and nerves. Modern treatment pairs immune-modulating drugs—most often the infused biologic rituximab—with a carefully tapered course of glucocorticoids to bring the disease into remission and then keep it there.

What Is ANCA-Associated Vasculitis?

Vasculitis simply means inflammation of blood vessels. In ANCA-associated vasculitis, that inflammation is driven by antineutrophil cytoplasmic antibodies (ANCAs)—autoantibodies that activate white blood cells called neutrophils, which then injure the walls of small vessels. When those vessels leak or clot, the organs they supply begin to fail.

AAV is an umbrella term covering three main conditions:

• Granulomatosis with polyangiitis (GPA) — often affects the sinuses, nose, lungs, and kidneys, and is frequently associated with PR3-ANCA antibodies.
• Microscopic polyangiitis (MPA) — commonly affects the kidneys and lungs, and is more often associated with MPO-ANCA antibodies.
• Eosinophilic granulomatosis with polyangiitis (EGPA) — linked to asthma, high eosinophil counts, and nerve or heart involvement.

Because AAV can involve life-threatening organ damage—particularly kidney failure and lung hemorrhage—prompt, aggressive treatment is the standard of care. According to the Vasculitis Foundation and the American College of Rheumatology, therapy is guided by whether the disease is active and severe (threatening an organ or life) or active but non-severe.

The Two Phases of Treatment

Treatment for AAV is divided into two distinct phases, and understanding the difference clarifies why the drug regimen changes over time:

• Remission induction — the intensive early phase, typically lasting several months, aimed at rapidly shutting down active inflammation.
• Remission maintenance — a longer, gentler phase that keeps the disease quiet and prevents relapse, often continuing for a year or more.

Both phases combine an immunosuppressive drug with glucocorticoids (steroids). What changes is the intensity and the specific agents used. The goal throughout is to control the disease while minimizing the cumulative toxicity of the medications themselves.

Rituximab: The Infusion Cornerstone

Rituximab is a monoclonal antibody given by intravenous (IV) infusion. It targets a protein called CD20 on the surface of B cells—the immune cells that produce the ANCA antibodies driving the disease. By depleting these B cells, rituximab interrupts the autoimmune attack closer to its source.

For patients with active, severe GPA or MPA, the 2021 ACR/Vasculitis Foundation guideline conditionally recommends rituximab over cyclophosphamide for remission induction. A major reason is safety: rituximab avoids much of the toxicity associated with cyclophosphamide, and it is often favored for younger patients concerned about fertility, as well as for those with relapsing disease.

Rituximab is also central to the maintenance phase. Major guidelines—including those from the ACR, KDIGO, and EULAR—favor rituximab for maintaining remission in GPA and MPA, typically given as periodic infusions after the induction phase is complete. Maintenance is especially important for patients at higher relapse risk, such as those with PR3-ANCA positivity or a history of prior relapses.

Because rituximab suppresses part of the immune system, patients are typically screened for infections such as hepatitis B before starting, and are monitored for infection risk during treatment. Infusion reactions can occur, so the first infusions are given slowly with premedication and close observation.

Cyclophosphamide

Before rituximab, cyclophosphamide was the mainstay of induction therapy, and it remains an important option—particularly for the most severe presentations or when rituximab is unsuitable. It can be given as an IV infusion or as an oral tablet, depending on the clinical situation.

Cyclophosphamide is highly effective but carries meaningful risks with cumulative exposure, including reduced fertility, bladder injury, low blood counts, and a higher long-term risk of certain cancers. Because of these concerns, guidelines generally recommend limiting its use—and specifically advise against cyclophosphamide for active, non-severe disease, where safer alternatives exist. When it is used, the total duration is usually kept as short as possible before transitioning to a gentler maintenance drug.

Glucocorticoids and Avacopan

Glucocorticoids—most commonly prednisone or IV methylprednisolone—are used alongside rituximab or cyclophosphamide during induction to bring inflammation under rapid control. They work quickly but cause well-known problems with prolonged use, including weight gain, high blood sugar, bone loss, and increased infection risk. For that reason, current guidance emphasizes reduced-dose steroid regimens and a steady taper rather than staying on high doses.

Avacopan (Tavneos): An Oral Steroid-Sparing Option

Avacopan, sold as Tavneos, is an oral medication approved by the U.S. Food and Drug Administration in 2021 as an add-on treatment for adults with severe active ANCA-associated vasculitis (GPA and MPA). It is not a replacement for rituximab or cyclophosphamide; rather, it is used together with standard therapy.

Avacopan works by blocking the C5a receptor, part of the complement system that fuels the inflammatory attack on blood vessels. Its main appeal is that it can help reduce reliance on glucocorticoids—an important goal, since much of the harm patients experience over time comes from long-term steroid exposure rather than the disease itself. Because avacopan is taken by mouth, it fits alongside infusion-based therapy rather than replacing it.

EGPA and Mepolizumab

Eosinophilic granulomatosis with polyangiitis (EGPA) has a distinct biology centered on eosinophils—a type of white blood cell—and is closely tied to asthma and allergic symptoms. This difference opens up a targeted treatment not used in GPA or MPA.

Mepolizumab, marketed as Nucala, is a biologic that blocks interleukin-5 (IL-5), a signaling molecule that drives eosinophil production. It was approved by the FDA in 2017 for adults with EGPA—the first therapy specifically approved for that condition. Importantly, mepolizumab is given as a subcutaneous injection (under the skin), not as an IV infusion. In studies, it increased time spent in remission, reduced relapses, and allowed many patients to lower their steroid dose.

For maintenance in EGPA more broadly, guidelines also describe conventional immunosuppressants such as methotrexate, azathioprine, or mycophenolate mofetil, with the choice tailored to disease severity and organ involvement.

Plasma Exchange and IVIG

Two additional therapies play supporting roles in select situations.

Plasma exchange (plasmapheresis) filters the liquid portion of the blood to remove circulating antibodies and inflammatory proteins. It is not used routinely for every patient. Instead, it is reserved for specific severe scenarios—classically certain cases of rapidly progressive kidney failure or diffuse alveolar hemorrhage (bleeding into the lungs)—where rapid removal of harmful antibodies may help. Its role has narrowed as evidence has evolved, and the decision is made case by case.

Intravenous immunoglobulin (IVIG) is generally considered an adjunct rather than a first-line treatment for AAV. It may be considered in select circumstances, such as persistent or relapsing disease when standard immunosuppression must be limited—for example, during active infection or pregnancy. If you’re new to this therapy, our guide to infusion therapy for autoimmune conditions explains how IVIG and other infusions are administered.

A Note on Other Vasculitis Types

ANCA-associated vasculitis is only one branch of a larger family. Other forms of vasculitis are classified by the size of the vessels they affect and are treated differently. Giant cell arteritis (GCA), a large-vessel vasculitis affecting older adults, is one example where a different biologic—tocilizumab, which can be given by IV infusion or subcutaneous injection—is used alongside steroids. The key point is that “vasculitis treatment” is not one-size-fits-all; the specific diagnosis determines the drug strategy, which is why accurate classification matters so much.

What to Expect as a Patient

AAV is usually managed by a rheumatologist or nephrologist, often with input from pulmonology, ENT, or other specialists depending on which organs are involved. Here’s a realistic picture of the journey.

Comparing the Main Therapies

Monitoring and Long-Term Care

Even after remission, AAV requires ongoing follow-up. Blood and urine tests track kidney function and signs of returning inflammation, and periodic visits help the care team catch relapses early. Because these medications suppress the immune system, vaccination status, infection prevention, and bone health are all part of comprehensive care.

If your treatment plan includes infusions, our directories can help you find infusion centers near you and connect with prescribers experienced in autoimmune and rare-disease care.