julie steenhuisen
April 7 (Reuters) – Nearly a third of patients with advanced liver cancer who received a personalized vaccine and immunotherapy drug developed by Geneos Therapeutics saw their tumors shrink in a small initial trial. U.S. researchers reported on Sunday that
The results were about twice the response typically seen with immunotherapy alone, the researchers said.
Preliminary research results presented at the American Association for Cancer Research in San Diego and published in Nature Medicine show that a vaccine based on mutations present only in a patient’s tumor could improve the immune system’s ability to recognize and attack hard-to-treat diseases. This suggests that it has the potential to enhance the ability of cancer.
This finding needs to be confirmed in larger trials, but after many past failures, the industry is one step closer to an effective cancer vaccine and the cancers that can be treated with such therapies. The variety may expand.
Partners such as Moderna Inc. and Merck & Co. have shown promising results in combining customized vaccines and immunotherapies to prevent skin cancer from recurring in patients after surgery.
In this study, researchers used samples taken from patients’ tumors to build a vaccine based on neoantigens (new mutations are only present in individual patients’ tumors). The goal was to train the immune system to attack and kill only these unique proteins while leaving healthy tissue intact.
Unlike skin cancer, which has many mutations that the body can recognize, liver cancer is considered a cold cancer because it has fewer mutations, making immunotherapy less effective.
“This vaccine essentially educates the immune system to recognize antigens that are ignored,” said study leader Dr. Mark Yachoan of the Johns Hopkins University Kimmel Cancer Center.
The study involved 36 patients with hepatocellular carcinoma, the most common form of liver cancer. Patients received a custom-made vaccine in addition to Merck’s immunotherapy Keytruda, which was widely used as standard treatment at the time.
Almost one-third (30.1%) of patients treated with the combination therapy experienced tumor shrinkage, and three of them had a complete response. This means that no detectable signs of tumor remained after a median follow-up of 21.5 months.
This compares to a typical response rate of about 12% to 18% for liver cancer patients who receive immunotherapy alone.
“This certainly suggests that the vaccine has indeed added clinical efficacy,” Yalchoan said.
The most common side effect was mild injection site reaction. There were no serious adverse events.
Unlike many vaccine candidates based on messenger RNA (mRNA) technology, the Geneos treatment is a DNA vaccine that uses tiny electrical impulses to inject the genetic code for a mutated protein into cells. Each vaccine can target up to 40 mutated genes.
Yachoan said larger trials are being planned, but did not provide details. (Reporting by Julie Steenhuisen; Editing by Bill Berkrot)
