A blood-based cancer test has shown promise in predicting how solid-cancer patients will respond to immunotherapy, according to the test’s developer, Chronix Biomedical.
The study, “Tumor Cell-Free DNA Copy Number Instability Predicts Therapeutic Response To Immunotherapy,” was published in the journal Clinical Cancer Research.
Cancer cells can have genomic copy number instability. This means that instead of having two copies of a gene — one from the mother, and one from the father — cancer cells can have just one copy, or more than two.
This feature, which helps them adapt to their environment, can be detected and quantified by analyzing cell-free DNA (cfDNA) circulating in the blood. That’s the basis of Chronix’s test.
Immunotherapy involves treating patients with drugs that boost the immune system’s response to cancer cells. Not all patients respond well, however: Some develop adverse side effects. And the treatment can be costly.
Predicting which patients will benefit from immunotherapy could help doctors offer the best guidance to those in their care.
Researchers decided to measure cancers’ response to immunotherapy by analyzing cfDNA sequences. They collected blood samples from 56 patients with advanced cancers. They included cancers of the lungs, kidneys, breasts, and pancreas, plus colorectal cancer, and melanoma.
All of the patients were receiving immunotherapy — mostly anti-PD1 antibodies — combined with chemotherapy.
Chronix’s test predicted treatment response and disease control or progression with 83 percent accuracy. It also predicted disease progression after one cycle of immunotherapy with 92 percent accuracy, and after two cycles with 100 percent accuracy.
In addition, the test identified six cases of cancer hyper-progression. Hyper-progression occurs when an immunotherapy accelerates tumor growth rather than slows it.
The test identified five hyper-progressions six to nine weeks earlier than other methods. It also detected progression of cancer in a patient whom other methods had misdiagnosed as having a stable disease.
Together, the results support the contention that Chronix’s test can be an early indicator of response to immunotherapy, with the potential to reduce patients’ disease burden and healthcare costs.
“The key finding is the ability of the test to make an early prediction of response and disease control, just three to four weeks after initiation of immunotherapy,” Glen Weiss, the study’s first author, said in a news release. “The flexibility to switch treatments early on based on an accurate prediction has great potential to improve the treatment of many cancers.”
“We are pleased to be able to share fully the details of this study with the oncology community, and highlight the performance of our … test, with the publication in Clinical Cancer Research,” said Howard Urnovitz, CEO of Chronix. “With advances occurring almost daily in the treatment of cancer with immunotherapy, we expect therapeutic monitoring of response to gain additional importance.”
