Long-term maintenance therapy with azathioprine (AZA) does not improve relapse rates in patients with anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV), according to researchers.
The study, “Long term azathioprine maintenance therapy in ANCA-associated vasculitis: combined results of long-term follow-up data,” was published in the journal Rheumatology.
A staged treatment approach, including remission-induction and remission-maintenance therapy, has been shown to work in AAV patients.
Remission-induction usually lasts for three to six months and is a combination of glucocorticoids with Rituxan (rituximab) or cyclophosphamide (CYC). Maintenance therapy, which prevents the disease from relapsing, can be achieved using drugs such as methotrexate (MMF) or azathioprine (AZA).
Despite this approach, disease relapses occur in half of patients within five years. And there is no consensus on the optimum duration of maintenance therapy.
Researchers at the University Medical Center Groningen in the Netherlands aimed to investigate whether the duration of AZA maintenance treatment affected relapse rates during a long-term follow-up study.
The study involved 380 patients from 70 hospitals in 15 countries who were diagnosed with AAV between 1995 and 2009. Patients received AZA therapy ranging from less than a year to 42 months. Patient follow-up continued after treatment was discontinued; the median follow-up time was 65.4 months.
Among patients who received AZA maintenance for over 18 months, 65.3% were alive and relapse-free at 60 months. For those who received the maintenance treatment for 18 months or less, the relapse-free survival rate was 55%, but the results were not statistically significant.
This showed that patients who continued receiving AZA maintenance therapy for more than 18 months did not show a significant improvement in relapse-free survival rates. Also, maintenance therapy duration did not affect infectious and cardiovascular adverse events in the patients.
Patients who had received CYC intravenously during the induction period had an increased relapse risk compared to those who received it orally. An increase in relapse risk was also associated with creatinine concentration at the time of diagnosis. Patients with PR3-ANCA were also found to be at a higher risk of relapse than those with MPO-ANCA. Therefore, the authors suggest that ANCA specificity could be used to tailor individual therapeutic regimens.
“There is no clear evidence that extension of maintenance therapy with AZA maintenance therapy beyond 18 months after diagnosis in general is effective in relapse prevention,” the authors concluded.
However, they point out that this “may not be applicable to certain groups of patients who may have higher risk of relapse or other specific characteristics.”