NEW YORK (Reuters Health) – Pemphigus patients with severe disease and those with persistent anti-desmoglein antibodies (DSG) three months after starting rituximab treatment are more likely to relapse while taking the drug, according to new post hoc analysis from a randomized clinical trial.
"The findings suggest that these 2 factors could help differentiate a subgroup of patients at high risk of relapse who could benefit from maintenance infusion with rituximab at month 6 from a subgroup of patients at low risk of relapse who do not require therapy. early maintenance. " Claire Mignard from the University of Normandie in Rouen, France, and her colleagues conclude in JAMA Dermatology.
In the RITUX 3 trial, 90 patients were randomly assigned to 1,000 mg IV of rituximab on days 0 and 14 and infusions of 500 mg, 12 and 18 months plus short-term prednisone (0.5 mg / kg daily for moderate pemphigus, 1.0 mg / kg a day for serious illness), or only short-term prednisone.
At two years, 89% of patients receiving rituximab were in complete remission without treatment, compared to 34% of those receiving corticosteroids alone. There were 11 relapses (23%) in the rituximab group and 20 (46%) in the standard treatment group.
Three of the relapses occurred after the second maintenance dose, the authors note, while eight occurred between month six and month 12, suggesting that an initial maintenance infusion at month 6 could benefit some patients.
They reviewed RITUX 3 data in 47 patients receiving rituximab to identify factors related to short-term relapse. Patients who started the study with a Pemphigus Disease Area Index score of 45 or higher, indicating severe disease and anti-DSG 1 antibody levels greater than 20 IU / ml and / or anti-DSG 3 antibody levels above 130 IU / ml, they were significantly more likely to relapse.
The positive predictive value for early relapse was 50% and the negative predictive value was 94%.
"The presence of at least 1 of the 2 factors associated with pemphigus relapse may help identify a group of patients at high risk of relapse who may benefit from a maintenance infusion of rituximab at month 6. Additional studies are needed to determine optimal doses of rituximab maintenance therapy, "conclude Dr. Mignard and colleagues.
Roche provided rituximab and helped finance the extension of the study follow-up period. One of the authors reports financial ties to the company.
SOURCE: https://bit.ly/39f9xej JAMA Dermatology, online March 18, 2020.