Immunotherapy with checkpoint inhibitors has ushered in a new era of cancer therapy, with some patients showing dramatic responses and significantly better outcomes than with other therapies across many cancer types. But some patients do worse, sometimes much worse.
A subset of patients who undergo immunotherapy experience unexpected, rapid disease progression, with a dramatic acceleration of disease trajectory. They also have a shorter progression-free survival and overall survival than would have been expected.
This has been described as hyperprogression and has been termed “hyperprogressive disease” (HPD). It has been seen in a variety of cancers; the incidence ranges from 4% to 29% in the studies reported to date.
There has been some debate over whether this is a real phenomenon or whether it is part of the natural course of disease.
HPD is a “provocative phenomenon,” wrote the authors of a recent commentary entitled “Hyperprogression and Immunotherapy: Fact, Fiction, or Alternative Fact?”
“This phenomenon has polarized oncologists who debate that this could still reflect the natural history of the disease,” said the author of another commentary.
But the tide is now turning toward acceptance of HPD, said Kartik Sehgal, MD, an oncologist at Dana-Farber Cancer Institute and Harvard University, both in Boston.
“With publication of multiple clinical reports of different cancer types worldwide, hyperprogression is now accepted by most oncologists to be a true phenomenon rather than natural progression of disease,” Dr. Sehgal said.
He authored an invited commentary in JAMA Network Openabout one of the latest meta-analyses (JAMA Netw Open. 2021;4[3]:e211136) to investigate HPD during immunotherapy. One of the biggest issues is that the studies that have reported on HPD have been retrospective, with a lack of comparator groups and a lack of a standardized definition of hyperprogression. Dr. Sehgal emphasized the need to study hyperprogression in well-designed prospective studies.
Existing data on HPD
HPD was described as “a new pattern of progression” seen in patients undergoing immune checkpoint inhibitor therapy in a 2017 article published in Clinical Cancer Research. Authors Stephane Champiat, MD, PhD, of Institut Gustave Roussy, Universite Paris Saclay, Villejuif, France, and colleagues cited “anecdotal occurrences” of HPD among patients in phase 1 trials of anti–PD-1/PD-L1 agents.
In that study, HPD was defined by tumor growth rate ratio. The incidence was 9% among 213 patients.
The findings raised concerns about treating elderly patients with anti–PD-1/PD-L1 monotherapy, according to the authors, who called for further study.
That same year, Roberto Ferrara, MD, and colleagues from the Insitut Gustave Roussy reported additional data indicating an incidence of HPD of 16% among 333 patients with non–small cell lung cancer who underwent immunotherapy at eight centers from 2012 to 2017. The findings, which were presented at the 2017 World Conference on Lung Cancer and reported at the time by this news organization, also showed that the incidence of HPD was higher with immunotherapy than with single-agent chemotherapy (5%).
Median overall survival (OS) was just 3.4 months among those with HPD, compared with 13 months in the overall study population – worse, even, than the median 5.4-month OS observed among patients with progressive disease who received immunotherapy.
In the wake of these findings, numerous researchers have attempted to better define HPD, its incidence, and patient factors associated with developing HPD while undergoing immunotherapy.
However, there is little so far to show for those efforts, Vivek Subbiah, MD, of the University of Texas MD Anderson Cancer Center, Houston, said in an interview.
“Many questions remain to be answered,” said Dr. Subbiah, clinical medical director of the Clinical Center for Targeted Therapy in the division of cancer medicine at MD Anderson. He was the senior author of the “Fact, Fiction, or Alternative Fact?” commentary.
Work is underway to elucidate biological mechanisms. Some groups have implicated the Fc region of antibodies. Another group has reported EGFR and MDM2/MDM4 amplifications in patients with HPD, Dr. Subbiah and colleagues noted.
Other “proposed contributing pathological mechanisms include modulation of tumor immune microenvironment through macrophages and regulatory T cells as well as activation of oncogenic signaling pathways,” noted Dr. Sehgal.
Both groups of authors emphasize the urgent need for prospective studies.
It is imperative to confirm underlying biology, predict which patients are at risk, and identify therapeutic directions for patients who experience HPD, Dr. Subbiah said.
The main challenge is defining HPD, he added. Definitions that have been proposed include tumor growth at least two times greater than in control persons, a 15% increase in tumor burden in a set period, and disease progression of 50% from the first evaluation before treatment, he said.
The recent meta-analysis by Hyo Jung Park, MD, PhD, and colleagues, which Dr. Sehgal addressed in his invited commentary, highlights the many approaches used for defining HPD.
Depending on the definition used, the incidence of HPD across 24 studies involving more than 3,100 patients ranged from 5.9% to 43.1%.
“Hyperprogressive disease could be overestimated or underestimated based on current assessment,” Dr. Park and colleagues concluded. They highlighted the importance of “establishing uniform and clinically relevant criteria based on currently available evidence.”