New mRNA 'cancer vaccine' trial launches in UK

An 81-year-old man from Surrey became the first patient in the U.K. to receive a new "vaccine" designed to treat solid-tumor cancers, such as the skin cancer melanoma.

Therapeutic cancer vaccines act as a kind of immunotherapy, meaning they help train the immune system to fight cancer cells. They're different from vaccines that prevent cancer, such as the HPV vaccine that's incredibly effective at preventing cervical cancer. In the U.S., there are a handful of therapeutic cancer vaccines approved for melanoma, prostate cancer and bladder cancer.

The new vaccine being tested in the U.K. and elsewhere around the world is called mRNA-4359, according to a statement from the Imperial College Healthcare NHS Trust, one of the institutions running the global trial. Similar to the Pfizer-BioNTech and Moderna vaccines against COVID-19, the treatment contains a genetic molecule called mRNA. This cousin of DNA can relay instructions to the protein-building factories in cells, prompting them to churn out specific proteins.

Related: Cancer vaccine helped keep melanoma under control for years in small study 

In the case of mRNA-4359, the vaccine instructs cells to make proteins commonly found on cancerous solid tumors. These proteins then get presented to the body's immune system, which builds up an arsenal to go after the cancer cells.

mRNA-4359 is considered a "ready-made" cancer vaccine — it's designed to be used in any patient with a particular type of cancer, off-the-shelf, because it goes after proteins commonly present on those tumor types. Other mRNA cancer vaccines in development are more personalized. For example, there's a pancreatic cancer vaccine that's made using genetic information drawn from a patient's own tumors. Thus, it's tailored to target proteins found on that specific patient's cancer cells. 

The mRNA-4359 trial is testing whether the vaccine appears safe and tolerable to human patients. It will both be tested in isolation and as an add-on to an existing immunotherapy called pembrolizumab. As a secondary measure, the trial organizers will also see whether the treatment shrinks the tumors of lung and skin cancer patients. The effectiveness of the vaccine will be probed further in future studies.

"This research is still in the early stages and may be a number of years from being available to patients," Dr. David Pinato, a clinician scientist at Imperial College London's Department of Surgery & Cancer and a consultant medical oncologist at Imperial College Healthcare NHS Trust, said in the statement. "But this trial is laying crucial groundwork that is moving us closer towards new therapies that are potentially less toxic and more precise."

The first person treated in the U.K. arm of the trial wishes to remain anonymous, but said "I was pleased to be offered a chance to take part in a new trial."

"Fundamentally, it's a relief. I knew from my original diagnosis that I had something that was never going to go away, or unlikely to go away," he said in the statement. The man has a treatment-resistant malignant melanoma and he'd already received a different immunotherapy and radiotherapy prior to the trial.

The trial is sponsored by the pharmaceutical company Moderna and set to recruit patients around the world over the next three years. Each patient will be followed up for a period of up to 34 months after treatment.

This article is for informational purposes only and is not meant to offer medical advice.

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