Correct!
4. 1 and 3
The use of antibodies against programmed cell death 1 (PD-1), which block inhibitory T-cell checkpoints, is a promising new therapy for advanced cancers. One example of drugs in this class is pembrolizumab which is a humanized IgG4 monoclonal antibody (mouse antibody grafted to human immunoglublin). The Dana-Farber Cancer Institute reported three patients with pneumonitis secondary to pembrolizumab (1). in these patients pneumonitis onset was 7 to 24 months after starting treatment (1). The CT findings included diffuse ground-glass opacities, reticular opacities, consolidation, traction bronchiectasis, and effusions and CT scans were interpreted as showing acute interstitial pneumonia, adult respiratory distress syndrome (ARDS) or nonspecific interstitial pneumonitis (NSIP). Others have reported similar cases with pembrolizumab and the closely related immunotherapy nivolumab (2,3).
Naidoo et al. (4) proposed an algorithm for possible interstitial pneumonitis secondary with immune checkpoint blockade. For patients with severe , life-threatening symptoms and/or worsening hypoxia they propose hospitalization and discontinuing the immunotherapy. They also recommend corticosteroids and prophylactic antibiotics while awaiting cultures. Lung biopsy is not necessarily wrong but give the excellent transbronchial biopsies it seems unlikely this would add much in this case.
Our patient had his pembrolizumab discontinued and was started on prednisone with rapid resolution of his symptoms and radiographic abnormalities.
References