[Rituximab for the treatment of poly- and dermatomyositis : Results from the GRAID-2 registry]

In the treatment of poly- and dermatomyositis, only a limited number of treatment modalities are established.

The goal of the GRAID-2 registry was to study off-label use of biologic drugs for this indication in Germany.

Analysis of the data of the GRAID-2 registry for poly- and dermatomyositis.

In 22 of the 23 patients in the GRAID-2 registry, rituximab (RIX) was administered, while 1 patient was given tocilizumab as off-label therapy. The 22 patients who received RIX treatment were analyzed. At the start of treatment, the following active manifestations were present: myositis (n = 18), lung involvement (mainly interstitial lung disease; n = 10), arthritis (n = 10), skin manifestation (n = 9), and Raynaud syndrome (n = 5). Nine of the patients were Jo-1-antibody positive. All patients had previous treatments with multiple conventional immunosuppressive drugs. Treatment with RIX was given as infusions of 1 g i. v., which were repeated after 2 weeks. Patients received a mean of 3.09 ± 2.27 infusions (equivalent to 1.5 cycles of 2 × 1 g, max. 5 cycles). Tolerability of RIX treatment was rated as very good in 16 of 22 patients (72%), good in 5 (23%), and moderate in 1 (5%). In all, 27 adverse events were documented, with the majority being infections, whereby 2 severe infections occurred (6.59 per 100 patient-years). Eighty six percent of the patients showed complete remission of their myositis and 79% of their arthritis. The mean value of creatinine kinase in plasma fell from 1505 ± 2534 U/l before the start of treatment to 39 ± 134 U/l at the last visit. Regarding lung involvement, 1 of 10 of the patients showed complete and 6 of 10 partial remissions. In 2 of 10 patients, lung disease was stable during treatment.

RIX is the preferred off-label biologic drug for poly- and dermatomyositis in Germany. In spite of a strongly pretreated group of patients, the tolerability is acceptable, although the patient number in this investigation is small. Moreover, the results lead to the assumption that the majority of the patients had a good or even very good therapeutic response to RIX.