Combination therapy improves survival in advanced bowel cancer
Last reviewed: 14.06.2024
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People battling advanced colon cancer may have a new treatment option that could extend their survival, a new study finds. The results were presented at the American Society of Clinical Oncology annual meeting in Chicago and should be considered preliminary until published in a peer-reviewed journal.
The combination of the two experimental immunotherapy drugs plus standard chemotherapy resulted in a median survival of 19.7 months in patients, compared with a median of 9.5 months in those who received only a targeted therapy called regorafenib.
“These results pave the way for further study of this promising treatment approach,” said first author Zev Weinberg, MD, PhD, co-director of the UCLA Health GI Oncology Program and an investigator at the Jonsson Comprehensive Cancer Center at UCLA Health.
The two experimental immunotherapy drugs, etrumadenan and zimberelimab, activate the immune system to target cancer cells. Both drugs are being developed by Arcus Biosciences.
According to the American Cancer Society, in 2024, about 106,590 new cases of colorectal cancer will be diagnosed in the United States, and about 53,010 people will die from the disease. It is the third leading cause of cancer death in men and the fourth leading cause of cancer death in women.
Early diagnosis of any cancer is key to controlling it, since cancers that have spread are much harder to treat.
The new study included 112 patients with metastatic colorectal cancer who had already undergone chemotherapy (regimens containing oxaliplatin and irinotecan).
These patients were randomly divided into two groups. Seventy-five received the combination of EZFB: etrumadenan/zimberelimab plus standard chemotherapy (called mFOLFOX-6 plus bevacizumab), while the remaining 37 received the targeted therapy regorafenib alone.
According to Cancer Research UK, regorafenib is a type of targeted cancer drug called a cancer cell growth inhibitor. It works by interrupting the signals cancer cells need to grow, and also prevents these cells from forming new blood vessels.
In the study, the combination therapy nearly doubled patients' overall survival compared with regorafenib and significantly improved "progression-free survival," which is the time without further cancer growth.
Progression-free survival with combination therapy was 6.2 months, compared with 2.1 months for those who received targeted therapy alone, the researchers reported.
Finally, “treatment with the new combination therapy partially or completely shrank tumors in 17.3% of patients,” according to a UCLA press release. "For patients receiving regorafenib alone, tumor reduction was observed in 2.7%."
“The improvement in both progression-free survival and overall survival with the EZFB combination represents a significant advance in the treatment of refractory metastatic colorectal cancer,” Weinberg said in a UCLA press release.
The combination regimen had an "acceptable safety profile," with side effects roughly equivalent to those experienced by patients receiving standard chemotherapy, Weinberg and colleagues noted.