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Introduction: In patients with chronic inflammatory diseases and multi-organ involvement, sequential targeted monotherapy may fail to provide sufficient disease control, while dose escalation can affect immune balance. Dual targeted therapy (DTT) is increasingly used in these refractory cases, yet real-world data on clinical outcomes, safety, and immunological effects are limited. Systematic immune phenotyping is not routinely performed, although it may support infection risk assessment and personalised treatment decisions.

Objectives: To characterise indications, treatment patterns and early safety outcomes of patients receiving DTT in a real-world, interdisciplinary setting, and to evaluate the feasibility of integrating longitudinal FACS-based immunomonitoring into routine care.

Methods: Patients with at least two clinically relevant inflammatory manifestations receiving DTT (bDMARD + bDMARD or bDMARD + JAK/TYK2 inhibitor) were prospectively enrolled. Standardised follow-up included disease activity, infection frequency and clinical response. Immunomonitoring comprised flow cytometry of B- and T-cell subsets and immunoglobulin levels. Patients are followed every 3–4 months with repeated clinical and immunological assessments within a rheumatology–dermatology–gastroenterology care pathway.

Results: To date, 35 patients have been enrolled; 16 completed Visit 1 and two Visit 2. Most presented combined articular–cutaneous, articular–gut, or joint–skin–gut manifestations. The most frequent DTT regimens were IL-23 + TNF-α inhibition (n=9) and IL-23 + JAK inhibition (n=3). Additional combinations included IL-23 + IL-1 blockade and IL-23 + TYK2 inhibition. Patients receiving combination of bDMARDs and erenumab or teriparatide served as internal comparators due to minimal expected immunological effects. No serious or opportunistic infections occurred; mild infections were outpatient-managed. FACS-based immunophenotyping was feasible in all cases. Initial results indicated divergent effects on T-cell counts depending on the DTT combination (increase under IL-23 + TNF-α; decrease under IL-23 + JAK). Changes in monocyte counts may reflect ongoing inflammatory activity. Longitudinal data collection is ongoing.

Conclusion: DTT represents an important therapeutic strategy for refractory multi-organ inflammatory disease. The study demonstrates that structured immunomonitoring can be successfully implemented and may help characterise safety and immune changes under DTT. Early observations show measurable alterations in immune cell subsets without corresponding increases in infection risk. This integrated approach offers a basis for future work on personalised immunomodulation and risk stratification.

Disclosures: The authors declare no conflicts of interest.

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