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• Posted May 6, 2024

Combo Therapy May Be Advance Against Liver Cancer

A new combination therapy appears to boost the response rate for liver cancer patients receiving immunotherapy, according to results from a phase 2 clinical trial.

The combo therapy involves bavituximab, a drug that neutralizes a fatty substance called phosphatidylserine that cancer cells use to avoid detection and attack by immune cells, researchers said.

Bavituximab essentially doubled the response of liver tumors to pembrolizumab (Keytruda), an immunotherapy drug approved in 2016 to treat various cancers. 

About 32% of liver cancer patients responded to the bavituximab/pembrolizumab combination, compared with about 16% response in previous studies for pembrolizumab alone, researchers said.

Pembrolizumab also works by blocking a means that cancer cells use to avoid attack from immune cells, but it blocks a different process than that targeted by bavituximab, researchers noted.

"This study shows the promise of improving the success of cancer immunotherapies by targeting other immunomodulating proteins simultaneously,"lead researcher Dr. David Hsieh, an assistant professor of internal medicine with the UT Southwestern Simmons Comprehensive Cancer Center in Dallas said in a news release.

The combo treatment targets hepatocellular carcinoma (HCC), the most common form of liver cancer.

For many years, the only treatment for HCC tumors that couldn't be surgically removed was a drug called sorafenib. Sorafenib slows the growth of tumor-feeding blood vessels, but extends survival by only a few months.

More recently, immunotherapies have emerged as effective treatments for HCC. Unfortunately, only a fraction of patients respond to these drugs when they're delivered alone, and combining multiple immunotherapies increased the risk of serious and sometimes deadly side effects.

For the new clinical trial, researchers recruited 28 patients with HCC to receive the combo bavituximab/pembrolizumab therapy and followed their progress for an average of nearly 29 months.

Two patients had a complete response, with no evidence of liver cancer on imaging scans taken at the end of the trial.

The combined therapy also halted progression in another 32% of patients, results show.

For those who responded to the combo therapy, it continued to shrink their tumors for an average 13 months, researchers said. Four patients were still responding to the combo therapy when the study ended.

Further, adding bavituximab did not appear to increase side effects over those that already accompanied pembrolizumab, researchers noted.

Based on these results, researchers said adding bavituximab to immunothereapy regimens in other cancers might potentially boost their effectiveness without doing added harm to patients.

The new study appears in the journal Nature Communications.

More information

The American Cancer Society has more about liver cancer.

SOURCE: UT Southwestern Medical Center, news release, May 2, 2024