Established patient-reported outcome (PRO) instruments may not measure the full spectrum of symptoms encountered by patients with rare diseases.

Multicentric Castleman’s disease (MCD) patients often describe a wide range of subjective symptoms, highlighting the impact of this disease on quality of life.

Previously, MCD was treated with nonspecific anti-proliferative therapies, which often failed to resolve interleukin-6-driven symptoms, such as fatigue, sweats, and malaise.

Siltuximab treatment enabled symptom improvement. Specifically, alleviation of fatigue was accompanied by other measures of improved functioning.