Rituximab, Cyclophosphamide Similar for Inducing EGPA Remission

Rituximab didn’t perform any worse or better at inducing remission after a year in patients with eosinophilic granulomatosis with polyangiitis (EGPA) than did conventional treatment with cyclophosphamide in the phase 3 REOVAS trial conducted in France.

Dr Benjamin Terrier

The B-cell–depleting agent also had a safety profile similar to cyclophosphamide during that window of time, Benjamin Terrier, MD, PhD, said in presenting results of the trial at the virtual annual meeting of the American College of Rheumatology. He is a professor of rheumatology at Cochin Hospital in Paris, the University of Paris, and vice president of the French Vasculitis Study Group.

“So some of the major adverse events that we can consider with this treatment, especially with cyclophosphamide and specifically the fertility issues and the cancer issues, the follow-up of this study does not allow us to evaluate the potential benefit of rituximab over cyclophosphamide,” Terrier said in an interview.

“But on the short-term study of 1 year, for which the major adverse events are infections, there is almost no difference between the two treatments,” he said. A total of 11 patients taking rituximab and 9 patients taking cyclophosphamide had infections in the study period.

The REOVAS trial randomly assigned 105 adult patients with EPGA, otherwise known as Churg-Strauss syndrome, to either rituximab (52 patients) or the conventional strategy using cyclophosphamide (53). The patients had either newly diagnosed or relapsing disease. There was no significant differences in average daily glucocorticoid use between the two arms.

Patient characteristics were similar in both arms, including the percentages of patients with severe disease. Overall, 60% in each group had a Five-Factor Score (FFS) of 0, while the remainder had an FFS greater than 1. The FFS is calculated by giving 1 point for the presence of each of the following: proteinuria greater than 1 g/day, serum creatinine greater than 140 micromol/L, GI involvement, cardiomyopathy, and CNS involvement.

The presence of each FFS component was similar between the groups at baseline, although 25% of the rituximab group and 30.2% of the conventional arm had myeloperoxidase-positive antineutrophilic cytoplasmic antibodies, and the absolute eosinophil count was 180 per mm³ in the former and 300 per mm³ in the latter.

Treatment outcomes at 6 months and 1 year were similar in both groups. At 1 year, remission occurred in 59.6% with rituximab and 64.2% with cyclophosphamide, Birmingham Vasculitis Activity Score equaled 0 in 85.7% with rituximab and 86.5% with cyclophosphamide, and prednisone dose was less than 7.5 mg/day in 77.1% with rituximab and 71.2% with cyclophosphamide.

The cumulative total weeks of complete remission was about 16 weeks in each group. Relapse-free survival, prednisone dosage, quality of life, and disease sequelae patterns also were similar.

Tailor Treatment Choice to the Patient

Despite the equivocal findings between the two treatments, Terrier said there may be individual patients for whom rituximab would be preferred to cyclophosphamide. “It’s not dependent on the disease by itself but more on the patients we want to treat,” he said. “And clearly if there is a young female patient who wants to get pregnant, knowing that rituximab is not superior but does not appear to be inferior to cyclophosphamide can be interesting.”

The researchers opted to test the superiority rather than noninferiority of rituximab versus cyclophosphamide because a noninferiority design would have required a larger patient population, “which is not possible for a disease like this one,” he said.

Dr Michael Putman

“Ostensibly, [the trial] failed to show superiority, but given its favorable side-effect profile, it may be sufficient to show it’s more or less the same,” Michael Putman, MD, MSc, an associate professor and director of the vasculitis program at the Medical College of Wisconsin, Milwaukee, said in an interview. However, he noted that the study didn’t include some phenotypes seen in patients with EGPA, “in particular patients with neurological involvement.”

Putman added that the French REOVAS findings support recommendations in the 2021 ACR/Vasculitis Foundation guideline for using rituximab as a possible first-line agent to induce remission in severe granulomatosis with polyangiitis and microscopic polyangiitis. “I was somewhat surprised by that,” he said of the ACR/VF recommendation. “These are the best data to date comparing rituximab to cyclophosphamide in EGPA. I would feel more comfortable using rituximab in cases where previously I would have reached for cyclophosphamide.”

He also concurred with Terrier’s comment that rituximab may be preferred in people of child-bearing age, even extending that to men. “Cyclophosphamide can be quite toxic in terms of ovarian toxicity and premature ovarian failure,” he said. “Young men or women of child-bearing age are a group in whom I would strongly consider using rituximab.”

The French REOVAS investigators’ future research into rituximab for EGPA will include long-term follow-up for relapse and the induction of remission, Terrier said.

Terrier disclosed relationships with Roche, Chugai, Vifor, LFB, Grifols, GlaxoSmithKline, AstraZeneca, Bristol-Myers Squibb, Octapharma, and Janssen. Putnam has no relevant relationships to disclose.

This article originally appeared on MDedge.com, part of the Medscape Professional Network.

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