Efficacy and safety of rozanolixizumab in severe fibromyalgia: a phase 2A randomised, double-blind, placebo-controlled, multicentre trial.

In 30 seconds

This phase 2A, multicentre, randomised, double-blind, placebo-controlled trial assessed rozanolixizumab in adults with severe fibromyalgia at seven sites in north west England. Among 63 participants, the primary outcome—change in Brief Pain Inventory interference at 12 weeks—favoured rozanolixizumab over placebo, with a least squares mean difference of -0·5 (80% CI -1·0 to -0·1; p=0·065). The result did not meet the conventional two-sided 5% significance threshold, and investigators concluded that the treatment did not show broad, meaningful efficacy at group level. No serious treatment-emergent adverse events were reported during rozanolixizumab treatment.

Key findings

• At 12 weeks, the BPI-SF interference difference was -0·5 (80% CI -1·0 to -0·1; p=0·065), favouring rozanolixizumab.
• The primary outcome was not significant at a two-sided 5% α level (95% CI -1·2 to 0·2; p=0·13).
• No serious treatment-emergent adverse events were reported among participants receiving rozanolixizumab.
• Headache was the most common treatment-emergent adverse event across the study.

Why it matters

The trial tests whether reducing IgG through neonatal Fc receptor targeting can improve severe fibromyalgia symptoms. Although the primary measure showed a modest difference under the prespecified one-sided threshold, the conventional two-sided analysis and the investigators’ interpretation do not support broad meaningful benefit. The findings also highlight that a biologically selected subgroup may need to be identified before this approach can be assessed further.

What to keep in mind

The trial was small, with 63 participants, and the primary result did not reach significance at a two-sided 5% α level. Participants were not selected for pathogenic IgG autoantibodies, which the authors suggest may have contributed to heterogeneity.