BACKGROUND Relapsing polychondritis is a rare autoimmune disease of unknown etiology. There are no defined protocols for treatment, and its management depends on the physician's knowledge and empirical experience. Various reports often highlight the insufficient efficacy of conventional disease-modifying anti-rheumatic drugs, and report controversial results associated with the use of different biologic agents. CASE REPORT The patient was a 32-year-old woman, previously diagnosed with ankylosing spondylitis. Four years after the initial diagnosis and following her second delivery, the patient presented with a refractory and aggressive relapsing polychondritis, which posed a significant challenge for treatment. Two months prior to the onset of the chondritis, the patient exhibited high disease activity of ankylosing spondylitis, with ASDAS-CRP 3.5 and BASDAI 6.0. After treatment failure using a combination of an anti-TNFalpha inhibitor and methotrexate, we achieved remission of both co-existing autoimmune diseases using an IL-17 inhibitor (secukinumab). CONCLUSIONS Further investigations are needed to better understand the pathogenesis of this rare condition. The existence of various reports on the controversial effects of treatment with different biologic agents, including IL-17 antagonists, raises several questions, including whether the onset of relapsing polychondritis is a side effect of the use of biologics or if it is an autoimmune disease that occurs independently of the treatment. This is the first time that the use of an anti-IL-17 agent is reported to have successfully suppressed an aggressive, progressive form of this disease, without any symptom-free period before the initiation of secukinumab.
