Atacicept in multiple sclerosis (ATAMS): a randomised, placebo-controlled, double-blind, phase 2 trial
文摘
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Summary
Background
Depletion of B lymphocytes is associated with suppression of inflammatory activity in multiple sclerosis. We aimed to assess the safety and efficacy of atacicept, a recombinant fusion protein that suppresses B-cell function and antibody production.Methods
<p>In this placebo-controlled, double-blind, 36-week, phase 2 trial (ATAMS) in Australia, Canada, Europe, and the USA, patients aged 18-60 years with relapsing multiple sclerosis were randomly assigned via an interactive voice response system in a 1:1:1:1 ratio, stratified by geographical region, to receive weekly subcutaneous injections with atacicept (25, 75, or 150 mg) or placebo. Both patients and study personnel were masked to treatment assignment. The primary endpoint was the change in mean number of gadolinium-enhancing lesions on T1-weighted MRI per patient per scan between weeks 12 and 36. Efficacy endpoints were analysed in the intention-to-treat population. Patients who completed week 36 were eligible to participate in a long-term extension study (ATAMS EXT), consisting of a double-blind phase followed by an open-label phase, for a total study time of up to 5 years. The study was terminated early after the independent data and safety monitoring board noted an increased annualised relapse rate with atacicept. The protocol was subsequently amended to include a 60-week safety follow-up, to allow treatment with approved multiple sclerosis drugs, and to change the primary endpoint to gadolinium-enhancing T1 lesions per scan during the entire double-blind period of ATAMS. Both the trial and the extension are registered with , numbers (ATAMS) and (ATAMS EXT).Findings
<p>Between April 23, 2008, and early study termination on Sept 11, 2009, 255 patients were randomly assigned: 63 to placebo, 63 to atacicept 25 mg, 64 to 75 mg, and 65 to 150 mg. 90 (35%) patients completed the week 36 treatment visit, 26 (10%) discontinued before study termination (including one who dropped out before receiving study treatment), and 139 (55%) discontinued because of study termination. During the double-blind period of ATAMS, annualised relapse rates were higher in the atacicept groups than in the placebo group (atacicept 25 mg, 0路86, 95% CI 0路43-1路74; 75 mg, 0路79, 0路40-1路58; 150 mg, 0路98, 0路52-1路81; placebo, 0路38, 0路17-0路87). Mean numbers of gadolinium-enhancing T1 lesions per scan were similar in all groups (25 mg, 2路26, 0路97-5路27; 75 mg, 2路30, 1路08-4路92; 150 mg, 2路49, 1路18-5路27; placebo, 3路07, 1路40-6路77). Seven patients (one taking placebo and six atacicept) discontinued treatment because of adverse events. One death occurred in the placebo group. During the safety follow-up, immunoglobulin concentrations and B-cell counts returned towards predose values and annualised relapse rates in the atacicept groups decreased until they were similar to that of the placebo groupInterpretation
<p>Increased clinical disease activity associated with atacicept suggests that the role of B cells and humoral immunity in multiple sclerosis is complex. For studies that explore therapeutic immunomodulation in multiple sclerosis, rigorous monitoring for negative effects on clinical and MRI outcomes is warranted.Funding
<p>Merck Serono (Merck KGaA) and EMD Serono (Merck KGaA).
