A new retrospective study concluded that rituximab (Rituxan) could benefit patients with seropositive palindromic rheumatism (PR)—a rare form of arthritis that often comes before rheumatoid arthritis (RA)—who have not responded to conventional synthetic disease-modifying antirheumatic drugs (csDMARDs).
PR is a rare condition that often precedes RA. Unlike RA, PR is characterized by temporary inflammatory episodes. While some patients could have episodes every day, others may go months without symptoms. An attack could last for several hours or days at a time. Episodes usually involve two to three joints, but different joints could be affected each time. Patients are normally asymptomatic between episodes and the disease does not cause lasting damage. However, about half of PR patients go on to develop RA. It is unclear what causes PR.
“Rituximab (RTX) provides significant clinical benefits in active rheumatoid arthritis (RA) patients with inadequate response to DMARDs and anti-[tumor necrosis factor],” the study authors wrote. “There is no data regarding efficacy of RTX in seropositive Palindromic Rheumatism (PR), a forerunner of RA.”
The researchers evaluated three-year data on seropositive (rheumatoid factor ± anti-cyclic citrullinated peptide) PR patients whose disease was uncontrolled (> 4 attacks/month) despite treatment with csDMARDs. Patients received an initial 500 mg rituximab dose and were given a second dose two weeks later if adequate/complete disease control was not achieved. Patients continued treatment with csDMARDs and were retreated with rituximab if they relapsed.
Disease Control Achieved with Rituximab
The study included 33 patients (79% female) with a mean age of 48.15 ± 14.2 years. Mean disease duration was 68.4 ± 68.2 months, and patients were followed for a mean 24.3 ± 10.8 months. Most patients (88%) were on combination DMARDs. All 33 patients achieved complete disease control with rituximab. Just under half (n = 15) of patients relapsed after a mean 10.4 ± 5.5 months but achieved remission after repeat rituximab infusions. There were no serious adverse events, and no one progressed to RA until the end of the follow-up period.
“Our study supports the hypothesis that B cells play an important role in the pathophysiology of PR and that the combination ([rituximab]+ conventional drugs) can prevent the disease evolution into RA,” the study authors wrote.
“Although it is a rare disease, we see palindromic rheumatism patients in India more often,” the researchers added. “As the symptoms are very debilitating in these patients, in those patients, not controlled on conventional drugs, rituximab offers newer promise in controlling the attacks and prevents further progression to RA.”