To the Editor Hyperprogressive disease (HPD) has recently been described as an acceleration in tumor growth rate (TGR), with varying numerical definitions, in the context of cancer immunotherapy.1,2 Ferrara et al3 recently analyzed the rate of HPD in patients with non–small cell lung cancer treated with immune checkpoint inhibitors (ICIs) and chemotherapy. We applaud the authors for conducting the first analysis, to our knowledge, of HPD associated with ICIs that includes a comparator arm, but we note a number of concerns.