Do biological agents improve health-related quality of life in patients with systemic lupus erythematosus? Results from a systematic search of the literature.

Despite an unprecedented rise in the number of biological therapies developed for systemic lupus erythematosus (SLE) during the last decades, most randomised clinical trials (RCTs) have failed to reach their primary efficacy endpoint. These endpoints mainly constitute composite outcomes that encompass disease activity indices derived from clinician-reported and laboratory data and do not necessarily reflect the patient perspective, as symptoms that represent major concerns to patients, such as fatigue, are seldom part of the evaluation. To overcome this limitation, patient-reported outcomes (PROs) constitute useful tools for evaluating the effect of an intervention on facets that are particularly relevant for the patients. In the present review, we performed a systematic literature search aiming to examine the effect of biological therapies on SLE patients' health-related quality of life (HRQoL) and fatigue in RCT and real-life settings. We summarised results concerning 14 different biological agents, the majority of which targeting B cells or type I interferons, and discuss strategies that have been used to analyse HRQoL data, putting emphasis on minimal clinically important differences and the potential use of PROs as distinct targets in treat-to-target approaches. Lastly, we discuss differences between generic and disease-specific PRO measures and highlight the need of using a combination thereof aiming to capture the patient perspective in a comprehensive manner.