People in Poland with antineutrophil cytoplasmic antibody (ANCA)-associated vasculitides (AAV) are treated according to existing guidelines, and the most common treatment-associated adverse event is infection, according to a nationwide study.
Advances in immune-suppressing therapies have greatly improved the outlook for people with AAV in recent years. “Despite this undeniable progress, the optimal treatment regimens are still being discussed and revised, with relevant difficulties related to the rarity of the diseases and scarcity of the large clinical trials,” the researchers said.
Monitoring of treatment and side effects is important, as is evaluating “whether real-world use agrees with established, evidence-based guidelines,” they said.
The researchers analyzed data from the Polish Vasculitis Registry (POLVAS), looking at treatment information on 625 people diagnosed with AAV between 1990 and 2016. This included 417 people with granulomatosis with polyangiitis (GPA), 106 with microscopic polyangiitis (MPA), and 102 with eosinophilic granulomatosis with polyangiitis (EGPA).
The number of cases in the study represents “the largest description of treatment strategies in AAV in Poland, and one of the largest ever reported,” the researchers said.
Immune-suppressing treatment regimens were assessed in two groups: induction therapies, defined as medications that led to remission, or, if remission was never attained, were given in the first six months of treatment; and maintenance therapies, those given after remission was induced or after six months.
The most commonly used induction therapies were glucocorticosteroids (GCs), which were given in 95.3% of cases. In 73.7% of cases, a GC ‘pulse’ — an infusion of a very high dose (500 mg or more) — was given. The second most commonly used induction therapy was cyclophosphamide (78.3%), followed by rituximab (9.3%).
The low frequency of rituximab use “was mainly due to the lack of [a] drug cost reimbursement program in our country at the time of data collection,” the researchers said, noting that a reimbursement policy for rituximab in Poland began in 2016.
GCs were the most common maintenance therapy, used in 84.3% of cases. “In most cases with available data, GCs were used for the whole time of observation,” the researchers wrote.
Some differences in treatment regimens were observed among the different AAV manifestations. For example, people with EPGA were significantly less likely to be given GC pulses during induction than those with GPA (39.6%, compared with 76.9%) or MPA (39.6%, compared with 78.4%).
In general, “EGPA patients were treated less aggressively than those with MPA or GPA,” the researchers wrote. That might be due to a “less severe course of EGPA, comparing to the other AAV entities,” though because severity data was not included in the analysis, they couldn’t be certain, they said.
There were changes in treatment trends over time. People diagnosed with AAV after 2010 were less likely to be given cyclophosphamide maintenance therapy than those diagnosed in prior years. The researchers said that was likely due to the publication of study results on the relative efficacy of cyclophosphamide compared with other maintenance therapies, which led to changes in treatment recommendations.
“Generally,” the researchers wrote, “AAV therapy was consistent with recently published guidelines.”
The most commonly reported treatment-related adverse event was infection, accounting for 38.8% of all such events.
People who developed infections were significantly more likely to have been given at least one GC pulse as part of induction treatment (75.2%, compared with 61.7%) and to require hemodialysis as part of treatment (29.38%, compared with 18.37%).
Infections were less frequent among those diagnosed after 2010. While that could reflect improvements in care, it could also be because people diagnosed more recently have had less time to acquire infections, the researchers said. Indeed, they said, people who had infections had been under observation in POLVAS for significantly longer than those who didn’t (a median of 4.75 years, compared with 2.75 years).