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Background/Aim: According to current estimates, approximately 5–8% of the population in Germany are diagnosed with an autoimmune disease, including various rare neurological and rheumatological disorders. In recent years, novel immunmodulatory drugs have been approved for some of these conditions. However, evidence on the effectiveness and safety of these drugs outside clinical trials remains limited. Therefore, within the CONTRIBUTE project, the real-world evidence is being investigated using various data sources reflecting usage of these compunds under real-life conditions.

This analysis aims to examine the adverse reaction profiles of novel drugs for selected neurological and rheumatological autoimmune diseases using the EudraVigilance database.

Methods: The analyses were conducted using the EudraVigilance database, which is maintained by the European Medicines Agency (EMA) and collects spontaneous reports of adverse drug reactions (ADRs). A retrospective, descriptive, indication-based analysis was conducted on spontaneous reports for all novel drugs approved between 2009 and 2023 for a rare neurological or rheumatological disease. For each disease, two case definitions (broad and narrow) were developed through a consensus process including clinical experts. Data were retrieved in June 2026. Reports not associated with one of the defined diseases were excluded from the analyses. Reactions that did not represent an explicit adverse reaction (e.g., the MedDRA preferred term ‘Off-label use’) were excluded. The analyses were conducted using Python (version 3.12.4) and Excel (version 2506).

Results: For belimumab used to treat systemic lupus erythematosus (SLE), 5,807 reports containing a total of 26,688 reactions were identified using the broad disease definition. Using the narrow disease definition, 5,777 reports containing 26,485 reactions were identified. For the broad SLE definition, 5,274 (90.8%) reports involved female patients, and 2,572 (44.3%) involved patients aged 18–64 years. The five most frequently reported reactions were ‘Systemic lupus erythematosus’, ‘Pain’, ‘Fatigue’, ‘Arthralgia’, and ‘Pyrexia’. Of the reported reactions, 18,219 were classified as serious (68.3%) of which 732 (2.7%) were associated with death, and 7,227 (27.1%) involved hospital admission or prolonged hospital stay. The characteristics of the reports were comparable between the two disease definitions.

Discussion/Conclusion: The evaluation of spontaneous adverse drug reaction reports provides insights into the safety profiles of novel drugs, including those used to treat rare diseases. These data can contribute to the assessment of the safety of these medicines under real-world conditions. The findings provide a basis for further discussion of potential safety signals and may support the generation of hypotheses for future pharmacoepidemiological research.