Atezolizumab results in survival benefit
Researchers who treated a group of postoperative bladder cancer patients with the immunotherapeutic drug atezolizumab found that patients whose blood contained circulating tumor DNA (ctDNA) responded very well to treatment .
The study is presented today at the annual congress of the European Association of Urology (EAU22), in Amsterdam.
The research was part of a larger phase III trial, IMvigor010, which investigated whether giving atezolizumab for one year to patients after bladder removal surgery improved patients’ prospects for survival, compared with to a group that received no other treatment after surgery but was placed in an observation group. Part of this trial involved measuring patients’ ctDNA levels after surgery and during subsequent treatment or observation.
Although the trial found no significant difference in overall survival between the two groups in the intent-to-treat population, the researchers noted that a subset of ctDNA-positive patients showed marked improvement when were receiving atezolizumab. These benefits included significantly higher disease-free survival and significantly higher overall survival than the observation group. This effect was not observed in ctDNA negative patients.
Additionally, the researchers also found that patients who were ctDNA positive, but then became ctDNA negative after treatment with atezolizumab, ultimately had a particularly good prognosis.
ctDNA includes fragments of DNA from cancer cells and tumors that are found in the bloodstream. Sometimes known as “liquid biopsy”, it has emerged as a promising, minimally invasive biomarker in clinical oncology, but is not yet widely used as part of a standard detection and treatment tool for all cancers. . This involves sequencing a tumor-specific gene for each patient, which is time-consuming and, at present, relatively expensive.
Professor Gschwend, Chairman of the Department of Urology at the Technical University of Munich, said: “We already knew that ctDNA positive patients have a poor prognosis compared to those who are ctDNA negative. But this is the first time we’ve been able to show that with immunotherapy we can actually alter disease course based on a patient’s ctDNA status. “
He continued: “If we can prove that the resulting drug activity is linked to ctDNA status, and that high-risk patients will benefit, this could ultimately change the standard treatment pathway – and ultimately make lower the average cost of ctDNA analysis. ”
Professor Morgan Roupret, President of the European Onco-Urology Section of the European Association of Urology, said: “The field of personalized medicine, using not only clinical but molecular indicators, is upon us. Thus, ctDNA analysis is very interesting. This is relatively easy to do with new technology and means we can select a subset of patients who are likely to respond.
The next step will be the next IMvigor 011 study, which has been redesigned as a result of these results. With 500 participants, the trial will further evaluate the use of ctDNA sampling and compare atezolizumab to placebo only in ctDNA-positive patients after surgery.
Professor Roupret added: “Unlike prostate cancer, where we can measure PSA as a cancer marker, until now we had nothing to use for bladder cancer. But these strong results show that this ctDNA has great potential as a sophisticated tool to monitor patients and choose their most effective treatment. The progress of the IMvigor 011 study will be closely monitored by specialists for better evaluation of the use of atezolizumab in patients with bladder cancer.
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