In Reply We would like to thank Yang and colleagues for their interest in our recent article1 and for providing their feedback. Herein we discuss the questions that they raised.
With regard to the duration of treatment as a potential confounding factor, a recent article reported that most irAEs occur within the first weeks to months after initiation of anti–programmed cell death 1 (PD-1) therapy.2 Although anti–PD-1 therapy is sometimes administered for months or even years, prolonged treatment does not appear to result in an increased cumulative incidence of irAEs.3,4 This finding suggests that therapy duration is unlikely to affect treatment efficacy. Nevertheless, it remains conceivable that longer therapy duration could increase the likelihood of irAEs, and further observational data are needed.