Tirabrutinib safe, effective for refractory pemphigus

Tirabrutinib induces remission and lowers oral corticosteroid exposure among patients with refractory pemphigus, a recent study has found.

Researchers conducted a multicentre, open-label, single-arm phase II study of 16 patients (mean age 52.5 years, 50 percent men) with refractory pemphigus being treated with oral corticosteroids and adjuvant therapies. Patients were also given 80 mg oral tirabrutinib once daily for 52 weeks. At week 16, oral corticosteroids were tapered to ≤10 mg/day.

At 24 weeks, the primary endpoint of complete remission rate was 18.8 percent (95 percent confidence interval [CI], 6.6–43.0). The cumulative remission and complete remission rates up to 52 weeks of treatment were 62.5 percent and 50.0 percent, respectively.

Tirabrutinib treatment likewise led to improvements in disease activity. The mean pemphigus disease area index (PDAI) score dropped from 9.9±7.1 at baseline to 5.5±7.3 at week 8, corresponding to a 58.9-percent reduction. PDAI was further reduced to 1.3±3.5 at week 52, a 90.2-percent decline relative to baseline.

Similarly, average prednisolone dose decreased with time after tirabrutinib treatment, dropping from 17.03 mg/day at baseline to 7.65 mg/day at week 52.

In terms of safety, 87.5 percent of participants (n=14) experienced adverse events (AE), while adverse drug reactions were detected in 43.8 percent (n=7). Common AEs included nasopharyngitis, influenza, pemphigus, and hypertension.

There were three cases of serious AEs and four of grade 3 AEs, all of which were deemed to be unrelated to tirabrutinib. Two AE-related discontinuations were reported, both likewise unrelated to tirabrutinib.