Pneumonitis and concomitant bacterial pneumonia in patients
Pembrolizumab, a monoclonal antibody against the programmed cell death 1 (PD-1) protein, can induce a stable regression of some malignancies refractory to conventional chemotherapy. Despite such therapeutic benefits, pembrolizumab can induce immune-related adverse events, with pneumonitis being the most critical problem.

All 3 patients complained of fever, cough, and dyspnea after a variable time interval (1–21 days) from pembrolizumab treatment. Chest computed tomography invariably showed ground glass opacity. All tests for possible infectious agents were negative. Based on high procalcitonin level, one of 3 patients was diagnosed to have accompanying bacterial pneumonia.

All patients received antibiotics and steroid treatments (methylprednisolone, 1 mg/kg) The 3 patients showed different clinical courses ranging from mild pneumonitis to rapidly progressing respiratory failure. Among the 3 patients, 2 fully recovered with steroid treatment; 1 died from superimposed bacterial pneumonia.

Source: Medicine: June 2019 - Volume 98 - Issue 25 - p e16158

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