BioNTech plans to begin clinical trials for its cancer vaccines in the UK this year, according to the company's CEO, Ugur Sahin quoted in the German press.
The drug developer, which is best known for its COVID-19 vaccine developed with Pfizer, is deciding which types of cancer it will test its personalised immunotherapies on and where the trials will be conducted.
The start of clinical trials marks an important step toward the possible sale of BioNTech's cancer vaccines on the open market.
With this in mind, we thought we’d take provide a two-minute guide to this emerging area of clinical research.
What are they?
Cancer vaccines are a type of treatment that stimulates the immune system to recognize and attack cancer cells. Unlike traditional vaccines that prevent infectious diseases, cancer vaccines are designed to treat cancer that has already developed in the body.
One type of cancer vaccine that is showing promise is the messenger RNA (mRNA) vaccine. mRNA is a molecule that carries instructions for making proteins. When mRNA is injected into the body through a vaccine, it instructs cells to produce proteins that may stimulate an immune response against these same proteins when they are present in cancer cells.
Dendritic cells, which are the sentinels of the immune system, are likely to take up mRNA from a vaccine. After taking up and translating the mRNA, dendritic cells present the resulting proteins, or antigens, to immune cells such as T cells, starting the immune response.
Challenges
One challenge for cancer vaccines is learning how best to identify the specific proteins or antigens on cancer cells that will provoke an immune response. A solution employed by some investigational cancer vaccines is to encase the mRNA in lipid nanoparticles or other delivery vehicles, which protect the mRNA molecules and enhance their effectiveness.
Some companies are investigating mRNA cancer vaccines that are based on collections of a few dozen neoantigens that have been linked with certain types of cancer, including prostate cancer, gastrointestinal cancers, and melanoma.
So what next?
In addition to clinical trials, fundamental research on mRNA cancer vaccines continues. Some investigators are trying to enhance the responses of immune cells to neoantigens in mRNA vaccines. A challenge for the field is learning how best to identify neoantigens for personalized mRNA cancer vaccines.
One of the biggest advantages of mRNA vaccines is that they can be manufactured quickly and inexpensively, which is especially important for personalised cancer vaccines. With this approach, researchers try to elicit an immune response against abnormal proteins, or neoantigens, produced by a patient's own cancer cells. The vaccine can include genetic sequences for up to 34 different neoantigens.
How close are we?
Some clinical trials of mRNA cancer vaccines have shown promising early results, particularly for personalized cancer vaccines. For example, a clinical trial testing a personalized mRNA vaccine in combination with an immune checkpoint inhibitor in patients with advanced head and neck cancer showed early signs of efficacy.
Among the first 10 participants, 2 patients had all signs of their tumours disappear following treatment, known as a complete response, and another five had their tumours shrink.
Overall, mRNA-based cancer vaccines hold great promise as a potential new tool in the fight against cancer. While more research is needed to better understand the relative advantages of different approaches, the success of mRNA COVID-19 vaccines could help accelerate clinical research on mRNA vaccines to treat cancer.