Rituximab induces good remission rates in pemphigus vulgaris

A single cycle of rituximab treatment for pemphigus vulgaris achieves >30 percent complete remission rate after 1 year, which improves with longer follow-up and additional cycles, a new study has found.

“This dataset of clinical and serological outcomes for pemphigus vulgaris patients after rituximab therapy will facilitate clinical trial planning and also guide clinician and patient expectations after rituximab therapy,” the researchers said.

They conducted a case review of all pemphigus vulgaris patients who sought care at the University of Pennsylvania from March 2005 to October 2017. A total of 107 patients received first rituximab therapy, while 63 were given second cycles.

The maximal rate of complete remission off oral systemic therapy (CROT) was 32.4 percent at 12 months after first rituximab treatment. Taking additional cycles into consideration improved 12-month CROT rate to 38.1 percent, and expanding follow-up to 36 months further upped CROT to 43.1 percent.

Among those who achieved CROT or CR, the cumulative probabilities of relapse were 61.5 percent and 51.5 percent, occurring after a median of 18.3 and 19.9 months after the first and second cycles of rituximab, respectively.

Linear mixed-effects models showed that desmoglein 3 (DSG3) levels could significantly predict CROT, such that those who achieved CROT saw a greater average monthly decline in DSG3 relative to non-CROT comparators (p=1.2×10^–6).

Receiver operating characteristic curve analysis revealed that the optimal threshold of >90.7 percent reduction in DSG3 titres from baseline to 3–9 months could predict CROT with 94 percent sensitivity. On the other hand, an absolute DSG3 titre ≤130 RU/mL between 3–9 months could predict CROT with 96 percent specificity.