(Reuters) – Almost 33% of patients diagnosed with advanced liver cancer who were administered a personalized vaccine developed by Geneos Therapeutics in combination with an immunotherapy drug in a small preliminary trial experienced tumor reduction, according to findings reported by U.S. researchers on Sunday.
The outcome was approximately twice as effective as the response typically seen with just the immunotherapy, as stated by the researchers.
The results from this initial study, unveiled at the American Association for Cancer Research conference in San Diego and published in Nature Medicine, propose that vaccines formulated based on mutations specific to an individual patient’s tumor could enhance the immune system’s capability to identify and combat challenging-to-treat cancers.
These findings, which will need to be confirmed in a larger-scale trial, put the medical industry closer to successful cancer vaccines, after numerous past disappointments, and could broaden the range of cancers that can be treated with such therapies.
Collaborators like Moderna, Merck and Co, and others have seen encouraging outcomes by combining tailored vaccines with immunotherapy to prevent the recurrence of skin cancer in patients post-surgery.
For this research, samples from the tumors of patients were utilized to create vaccines founded on neoantigens – new mutations exclusively present in an individual patient’s tumor. The objective was to train the immune system to target and eliminate only these distinct proteins, leaving healthy tissues unharmed.
Unlike skin cancer, which contains numerous mutations for the body to recognize, liver cancer is viewed as a cold cancer due to its fewer mutations, making immunotherapies less effective.
“This vaccine essentally educates the immune system to identify antigens that it has been ignoring,” mentioned Dr. Mark Yarchoan, the lead researcher from Johns Hopkins Kimmel Cancer Center.
The study enrolled 36 patients diagnosed with hepatocellular carcinoma, the most prevalent form of liver cancer. Patients received personalized vaccines in conjunction with Merck’s commonly used immunotherapy drug Keytruda, the standard treatment approach at that time.
Approximately a third of the patients treated with the combined therapy (30.1%) observed tumor shrinkage, with three of those patients achieving a complete response, indicating no evident signs of the tumor post a median follow-up of 21.5 months.
This is in contrast to the usual response rate of around 12% to 18% in liver cancer patients who solely undergo immunotherapy.
“This certainly implies that the vaccine contributed to clinical effectiveness,” remarked Yarchoan.
The most common adverse reaction noted was mild reactions at the injection site, with no severe adverse events reported.
As opposed to numerous vaccine candidates based on messenger RNA (mRNA) technology, the Geneos treatment is a DNA vaccine where the genetic code of mutated proteins is injected into cells using a slight electrical impulse. Each vaccine can target up to 40 mutated genes.
Yarchoan disclosed that larger trials are in the pipeline, although he refrained from providing specifics.
(Reporting by Julie Steenhuysen; Editing by Bill Berkrot)
