Trial Shows Results for Personal Cancer Immunotherapies

DNA plasmid illustration (DataBase Center for Life Science, Wikimedia Commons, https://commons.wikimedia.org/wiki/File:201907_PlasmidDNA_S.svg)

7 Nov. 2022. Interim results from a clinical trial testing personalized therapies invoking the immune system show responses from some patients with advanced liver cancer. Researchers for Geneos Therapeutics Inc. in Plymouth Meeting, Pennsylvania are scheduled to present the findings on Wednesday at the Society for Immunotherapy of Cancer or SITC annual meeting in Boston.

Geneos Therapeutics is a biotechnology company developing therapeutic vaccines that generate an immune response to attack cancerous tumors. The company’s technology produces synthetic DNA plasmids, circular DNA molecules addressing neoantigens emitted by tumors. Geneos says these neoantigens, made of peptides or short chains of amino acids, help define specific types of cancers, but also an individual’s own personal genomic makeup. With these neoantigens as targets, says Geneos, it can create vaccines designed to produce immune responses that reflect a person’s specific chemistry.

As reported by Science & Enterprise in Feb. 2019, Geneos Therapeutics is spun-off from another biotech company Inovio Pharmaceuticals, also in Plymouth Meeting. Inovio also creates DNA plasmids as therapies, and aids their delivery with electroporation, brief electronic pulses sent into target cells that increase uptake of DNA plasmids. Plus, Geneos adds a second plasmid encoded with the immune system protein interleukin-12, as a supplement at the local injection site.

The early- and mid-stage clinical trial is enrolling 36 people in the U.S. and New Zealand with advanced cases of hepatocellular carcinoma or HCC, a common form of liver cancer. Participants receive the immunotherapy pembrolizumab, the standard of care for HCC, as well as personalized immunotherapies targeting cancer-causing neoantigens, and an interleukin-12 supplement, plus electroporation.

All produced potentially cancer-killing T-cells

The study team is looking primarily for adverse effects exhibited by participants and immune system responses, particularly anti-cancer T-cells in blood samples over two years. In addition, the team is tracking several measures of anti-tumor activity and survival times of participants for this period. The trial has no placebo or comparison group.

The conference paper reports on the first 24 participants in the trial. Of this group, 23 individuals are still taking part. The company says one participant had to discontinue due to a severe adverse effect unrelated to the therapy. Of the remaining participants, none so far exhibited any more than mild or moderate temporary adverse effects.

The researchers say all of the participants produce CD8-positive T-cells, indicating a potential cancer-killing immune response, which by nine weeks after treatment travel to the tumor microenvironment, the surrounding support system for tumors. So far, says the team, seven of the 24 participants exhibit at least a partial response to the treatment, according to current evaluation guidelines for solid tumors. Of this sub-group, two patients show a complete response, and a third is cancer-free after subsequent surgery and radiation treatment.

Edward Gane, professor of medicine at the University of Auckland in New Zealand, is giving the SITC conference paper.”To see three cancer-free patients out of 23 evaluable in second-line advanced HCC,” says Gane in a Geneos Therapeutics statement, “with a treatment this well tolerated, tells me that personalized therapeutic cancer vaccination may now, finally, be here to stay.” The company says it’s planning for a more conclusive clinical trial with evidence needed by regulators.

More from Science & Enterprise:

• Dual-Action Vaccine Shown to Attack, Shrink Solid Tumors
• Immunotherapy Start-Up Launches Collaboration, Raises $65M
• RNA Cancer Immunotherapy Shown Feasible in Preclinical Test
• Cell, mRNA Therapy Biotech Raises $165M in Early Funds
• Precision Meds Shown Effective in Rare Cancer

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