Remission rate, treatment response varies by AAV type: Study
GPA patients more likely than those with MPA to see disease recur
The likelihood of disease recurrence in people with anti-neutrophilic cytoplasmic autoantibody (ANCA)-associated vasculitis (AAV) varies by disease type, with those with granulomatosis with polyangiitis (GPA) more likely to see their disease come back following successful treatment than people with microscopic polyangiitis (MPA), a study found.
Patients with MPA may be more likely to experience worsening kidney function, especially if they are initially treated with rituximab, data showed.
The researchers said the findings emphasize the importance of individualized treatment approaches.
The study, “Remission induction therapies and long-term outcomes in granulomatosis with polyangiitis and microscopic polyangiitis: real-world data from a European cohort,” was published in Rheumatology International.
AAV is a group of autoimmune diseases characterized by inflammation in blood vessels, potentially leading to organ damage, with kidneys being particularly susceptible. GPA and MPA are the most common types of AAV. While both cause inflammation in blood vessels and affect organs like the kidneys, GPA is characterized by the formation of small nodules called granulomas in various organs, while MPA primarily causes inflammation in small blood vessels without the presence of granulomas.
Studying remission rates
Treatment of AAV generally involves medicines to suppress immune activity. Patients are usually given an initial round of therapy, or induction treatment, aiming to drive the disease into remission. Once the induction treatment brings the disease under control, patients may continue taking maintenance therapies to remain in remission.
The scientists reported on outcomes from 358 people with AAV at centers in Germany and Switzerland who were diagnosed between 1999 and 2022. Nearly two-thirds of these patients had GPA, and about one-third had MPA. The researchers noted that GPA patients had higher disease activity, but MPA patients were more likely to have kidney involvement.
“With the present retrospective data analysis from a large, multicentric cohort of AAV patients we thought to shed light on several clinical key aspects and developments obtained from ‘real-world’ observations over more than 20 years,” the team wrote.
The most common induction therapy, used by more than half of the patients, was cyclophosphamide, which has long been a mainstay AAV treatment. Use of rituximab as induction treatment was less common, though the researchers noted that rituximab was used more often in more recent years. The most common maintenance therapies used were azathioprine and rituximab.
Results showed that, in both GPA and MPA, most patients (80.9%) were in complete remission one year after being diagnosed with AAV. However, with a median follow-up time of nearly five years, data showed that 41.3% of patients with GPA experienced a relapse in which disease symptoms returned following a period of remission. By comparison, 25.9% of patients with MPA experienced a disease relapse.
“MPA patients with renal manifestation were more likely to develop unfavorable renal outcomes over a five-year period, particularly in those MPA cases that received [rituximab] as remission induction,” the researchers wrote, though they noted that rituximab induction was generally effective overall.
The data highlight a need for personalized consideration when deciding which therapies to use for induction treatment, the researchers said.
“Our analysis advocates for more individualized therapeutic approaches using adjunctive treatment beyond [rituximab] in MPA patients with significant renal involvement,” the scientists wrote. “These patients experience more adverse renal events, if treated exclusively with [rituximab] instead of [cyclophosphamide], even though, our data strongly support effectiveness of [rituximab] in induction and preventing relapses in both GPA and MPA patients.”
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