Development of psoriatic arthritis during nivolumab therapy for metastatic non-small cell lung cancer, clinical outcome analysis and review of the literature.

Lung cancer is the leading cause of cancer-related death worldwide. The most common type, non-small cell lung cancer (NSCLC), is further divided into two main types, squamous cell and non-squamous cell (which includes adenocarcinoma). Nivolumab, a fully human IgG4 programmed death-1 immune checkpoint inhibitor antibody, has shown not only an overall survival advantage when compared to docetaxel, but also a relatively good side-effect profile among patients with previously treated advanced squamous and non-squamous NSCLC. Psoriatic arthritis (PsA), a heterogeneous chronic inflammatory disease, has a wide clinical spectrum and a variable clinical course that affects mainly musculoskeletal structures, skin and nails. Here we report the second case to the best of our knowledge of PsA development during nivolumab therapy. It is important to note that arthritis activity decreased without nivolumab discontinuation with the use of naproxen and a low dose of corticosteroid. Furthermore, a minimal disease activity was achieved adding methotrexate to the treatment and antitumor therapy efficacy was not influenced (a partial response was documented after eight and 39 cycles of nivolumab). Rheumatic immune-related adverse events management is a challenge and a coordinated multidisciplinary management by medical oncologists, rheumatologists and immunologists will be mandatory in the near future.