Data collections and secondary endpoint results
The researchers obtained data on 194 patients in the registry who were treated for GPA between April 2008 and April 2018. The majority (85.1%) of patients included were newly diagnosed with GPA, and 56.7% were men. The mean age of patients was 54 years.
Information on the PR3-ANCA status of patients was available for 182 patients, and this showed that the majority (80.8%) were positive for this autoantibody.
A weighted analysis was undertaken to iron out any differences in baseline characteristics, such as the fact that more patients had been treated with at least one dose of cyclophosphamide than rituximab (133 vs. 61).
The primary outcome was remission at 6 months, but a key secondary endpoint was the percentage of patients with a BVAS score of zero at this time point. This turned out to be similar among the rituximab- and cyclophosphamide-treated patients (85.5% vs. 82.6%, respectively).
Another secondary endpoint looked at the retention rate without failure at 24 months, with fewer postinclusion treatment failures seen with rituximab than with cyclophosphamide (7 vs. 51 patients, respectively). Most treatment failures were caused by relapses (7 vs. 33).
In terms of safety, the researchers said they found “no increased toxicity signal” for rituximab over cyclophosphamide. In fact, more severe adverse events were noted in the latter group.
Take-home messages
While of course there are limitations, considering the earlier data and the current results, “we probably have enough data to consider that, in the vast majority of GPA patients, in PR3-ANCA patients, rituximab is probably the best option,” Dr. Terrier said.
There are still patients for whom there isn’t a definitive answer on which drug may be best, such as those with severe disease who were not included in the trials or represent few patients in the registry. For them, it is “still a case-by-case discussion, and I think we have to decide really, with caution,” Dr. Terrier said.
What this study also shows is that emulated trials are possible, he added. “I think it shows that we could have some answers to other questions by emulating trials in this rare disease.”
The FVSG registry has received funding from the European Union’s Horizon 2020 research and innovation program. Dr. Terrier reported receiving personal fees from Vifor Pharma Group, GlaxoSmithKline, and AstraZeneca during the conduct of the study. Dr. Jayne has received lecture fees and a research grant from Roche/Genentech.