This is unpleasant: a paper published in Clinical Cancer Research described a pattern of “hyperprogression” identified in patients treated with PD-1/PD-L1 inhibitors in clinical trials at Gustave Roussy. The investigators compared tumor growth rate (TGR) prior to treatment with PD-1/PD-L1 agents with the TGR after, defining hyperprogression as greater than or equal to a two-fold increase of the TGR between the reference and post-treatment periods (and here I thought the worst thing that could happen was toxic epidermal necrolysis; see Google Images for more on that one). In the evaluable population of 131 patients, 9% met the definition of hyper-progressive disease, which was associated with older age and shorter OS.

While time to progression generally decreases with lines of treatment, a 2x+ increase in rate of growth seems particularly dramatic, and it’s another blemish on what was considered for a while a unicorn of cancer therapy. Continue reading ““Hyperprogression” identified as a risk of checkpoint inhibitors” →