Long-term pemphigus remission associated with first-line rituximab therapy

Key takeaways:

• Patients with pemphigus treated with rituximab had a longer disease-free survival than those treated with prednisone alone.
• First-line vs. second-line rituximab treatment also had a better disease-free survival.

An association with long-term complete remission was found in patients with pemphigus who used rituximab as first-line therapy, according to an extension study.

“Pemphigus is a rare, life-threatening auto immune bullous disease affecting the skin and mucosae,” Billal Tedbirt, MD, of the department of dermatology at CHU Rouen, and colleagues, wrote. “It is characterized by pathogenic IgG antibodies directed against 2 desmosomal adhesion proteins, desmoglein (Dsg) 1 and Dsg 3 (1-5).”

The Ritux 3 clinical trial previously found 89% of patients with pemphigus treated with rituximab and prednisone experienced complete remission compared with 34% of those in the prednisone-only group.

In this long-term follow up, 83 of the 90 patients randomly assigned in the Ritux 3 trial were evaluated again after a median of 7.3 years.

Complete remission occurred in 43 of the 44 (93.5%) patients in the rituximab plus prednisone group, compared with 17 of the 39 (38.6%) patients in the prednisone alone group.

Using Kaplan-Meier curves, the researchers compared 5- and 7-year disease-free survival (DFS) without corticosteroids and found those in the rituximab group had significantly longer DFS.

The rituximab group had 5-year DFS of 76.7% and 7-year DFS of 72.1%, compared with 35.3% and 35.3% for those in the prednisone only group, respectively (P < .001).

Relapses occurred in approximately 42.2% of the rituximab cohort, compared with 83.7% of the prednisone-only cohort (P < .001). In the rituximab plus prednisone group, 19 patients had at least one relapse, with a mean total of 1.84 relapses per patient. In the prednisone-only group, 36 patients had at least one relapse with a mean total of 3.2 relapses per patient.

Of 23 patients who were originally in the prednisone-only group and switched to be treated with rituximab as second-line treatment after relapse, 14 (60.9%; 95% CI, 38.5%-80%) experienced a new relapse. Additionally, 2- and 3-year DFS rates were significantly lower than those who were treated with rituximab as first-line therapy (39.2% and 17.4% vs. 75.6% and 75.6%; P = .007).

“This long-term evaluation of the Ritux 3 trial essentially showed that, after a median follow-up of 7.3 years, the relapse rate in patients initially randomized in the rituximab plus prednisone group was 2-fold lower than that of patients in the prednisone-alone group,” the authors wrote.