Sadly, a new study shows that out of a total population of 131 patients with various sorts of tumors treated with anti-PD-1 or anti-PD-L1 monotherapy, 12 of these (9%) had hyperprogressive disease (HPD) following treatment, defined as an increase in tumor growth rate at least 2 times higher than the reference growth rate (before anti-PD-1 treatment). The subset of patients with hyperprogressive disease were older on average than the rest of the cohort (66 versus 55 years on average). "At progression, patients with HPD had a lower rate of new lesions than patients with disease progression without HPD".
The mechanism for this increased tumor growth rate in this small subset is currently unknown.
"By RECIST, a total of 49 (37%) 66 (50%) 15 (12%) and 1 (1%) patients exhibited
progressive disease, stable disease, partial response or complete response,
respectively". Therefore, stable disease was the most common response overall.
The study was published today (November 8) as an OnlineFirst article by Clinical Cancer Research.
Click here for abstract
I've uploaded the full study to the Library, Immunology and Immunotherapy folder, Immune Checkpoint Inhibitor subfolder