Background: The therapy of patients with concomitant multiple sclerosis (MS) and ankylosing spondylitis (AS) is a challenge for clinicians. Secukinumab is effective in the treatment of MS. In the clinical case, we present, substantial clinical and radiological remission in the case of both autoimmune diseases was observed. Case Presentation: A male adult was diagnosed with relapsing-remitting MS. The patient complained of severe thoraco-lumbar pain. Magnetic resonance imaging (MRI) led to a diagnosis of AS. Considering that nonsteroidal anti-inflammatory drugs were ineffective and tumor necrosis factor-α blockers are contraindicated in patients with MS, secukinumab was prescribed. MRI 8 months after initiation of therapy provided clinical stability in consideration of the two autoimmune comorbidities. Conclusion: Secukinumab is an effective therapy for concomitant MS and AS.

Keywords: Multiple sclerosis, ankylosing spondylitis, secukinumab, autoimmune disease, case report.