medwireNews: Mavrilimumab is effective for reducing the risk for flare and maintaining sustained remission in patients with giant cell arteritis (GCA), phase 2 study findings show.
Presenting the results at the ACR Convergence 2020 virtual meeting, Maria Cid (Hospital Clinic Barcelona, Spain) reported a significant 62% reduction in the risk for flare over a 26-week period among patients receiving mavrilimumab, a human monoclonal antibody that inhibits human granulocyte macrophage colony-stimulating factor receptor, relative to placebo.
She highlighted in the late-breaking abstracts session the “unmet need for new treatment options for patients with GCA particularly for those with relapsing/refractory disease.”
Cid explained that, while tocilizumab combined with prednisone taper decreases the risk for disease relapse, “a substantial proportion of patients treated with tocilizumab fail treatment due to relapse or tocilizumab-related side effects.”
Half of the 70 patients in the current study had new-onset GCA and half had relapsing/refractory disease. Cranial clinical manifestations predominated (76%), and diagnosis was confirmed by ultrasound for the majority (73%). They all had active disease within 6 weeks of starting the trial, at which point they were required to be in glucocorticoid-induced remission.
Treatment consisted of random assignment to subcutaneous mavrilimumab 150 mg or placebo every 2 weeks in addition to prednisone taper starting at 20–60 mg/day for 26 weeks. This was followed by a 12-week washout safety period.
In all, 19.0% of the 42 patients randomly assigned to receive mavrilimumab had flared by week 26, with flare defined as an erythrocyte sedimentation rate of at least 30 mm/hour and/or a C-reactive protein level of 1 mg/dL or above, alongside re-appearance of GCA symptoms or new or worsening vasculitis on imaging. This compared with 46.4% of 28 placebo-treated patients, giving a 27.4% reduction in incidence in favor of mavrilimumab.
The median time to flare could not be estimated for mavrilimumab-treated patients because there were not enough events, whereas it was 25.1 weeks among those taking placebo.
Patients in the mavrilimumab treatment group were also a significant 33.3 percentage points more likely to be in sustained remission at week 26 than those in the placebo group, at 83.2% versus 49.9%.
Cid noted that the findings were consistent across the new-onset GCA and relapsing/refractory subgroups, “although they did not reach significance because the study was not sufficiently powered in these two subgroups.” She reported a 71% reduction in the risk for flare among new-onset patients taking mavrilimumab versus placebo and a 57% reduction in relapsing/refractory patients.
Mavrilimumab was generally well tolerated, with adverse events mainly mild to moderate and comparable across the treatment groups. There were two serious adverse events in the mavrilimumab treatment group and three in the placebo group, but Cid pointed out that “none of these were considered drug related,” and there were no cases of vision loss and no deaths.
Cid said that the “trial met its prespecified primary and key secondary efficacy endpoints,” and that “other secondary and exploratory endpoints are currently being analyzed.”
She concluded that the results “are encouraging for the potential further development of mavrilimumab in giant cell arteritis.”
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