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Therapeutic cancer vaccines are bringing new hope to tumor treatment, but many challenges remain. Recent clinical trials, including mRNA-based vaccines, are showing encouraging results, although their long-term efficacy remains to be proven. Between innovative treatments and scientific hurdles, could these vaccines revolutionize oncology in the years to come?
Preliminary data from a first-in-human study of an experimental messenger RNA immunotherapy (mRNA-4359), one of several cancer vaccines in clinical trials worldwide, were presented Saturday at the Oncology Congress in Barcelona.
Several studies presented at the ESMO 2024 congress
Sponsored by the American laboratory Moderna, the study showed that the therapy which targets patients with lung cancer, melanoma and other solid tumors, “is well tolerated, without serious side effects, and may boost the body’s immune system to treat cancer more effectively“, said the head of the UK trial, Dr Debashis Sarker of King’s College London.
“However, this study has only involved a small number of patients so far, so it is still too early to say how effective this treatment might be for people with advanced cancer.“, he tempers.
Cancer vaccine: ongoing studies
Research on therapeutic anti-tumor vaccines has a relatively long history, but without significant success on a large scale so far. Dozens of clinical trials are underway, but how many will have conclusive final results after being tested in randomization on a significant number of patients?
Currently, the most advanced experimental therapeutic vaccine, the Tedopiis being developed by French biotech company OSE Immunotherapeutics in patients with advanced non-small cell lung cancer.
Tedopi is also being studied at an earlier stage (phase 2) in pancreatic cancer and ovarian cancer. In patients with head and neck cancer, phase 2 clinical trials are being conducted on an mRNA vaccine from the German biotech company BioNtech and on an individualized vaccine therapy (TG4050), the flagship product of the French company Transgene.
The American laboratory Moderna, one of BioNTech’s rivals, hopes that its therapeutic vaccine against skin cancer, currently in trials, will be approved as early as 2025.
Therapeutic vaccines are designed to treat existing cancer rather than prevent its occurrence. They are a mainstay of immunotherapy.
“The goal of a therapeutic cancer vaccine is to elicit a cellular immune response capable of destroying tumor cells while preserving healthy tissues.“, explains Olivier Lantz, head of the clinical immunology laboratory at the Curie Institute.
“The immune system is trained to recognize tumor cells“to eliminate them,” he adds. These vaccines target mutations (neoantigens) in the cells that make up tumors. But decoding all the possible mutations is a long-term task, which complicates the development of therapeutic vaccines against cancer.
mRNA is one method for teaching the immune system to recognize these neoantigens to fight the tumor, but researchers also use viral vectors or peptides.
Generic and personalized vaccines
There are two main categories of therapeutic anti-cancer vaccines: generic vaccines for a given tumor type and personalized vaccines adapted to each patient.
Generic vaccines target antigens common to different individuals that are expressed in the same way by tumor cells.
Personalized vaccines target antigens that are unique to each tumor and patient. They are complicated and expensive to manufacture.
“For now, vaccination trials are reserved for patients who are either already advanced or metastatic, or people who have had tumors with a risk of recurrence.“, Mr. Lantz emphasizes.
Can we hope for a future launch on the market?
Asked by The ParisianCyrille Cohen, director of the immunotherapy laboratory at Bar-Ilan University in Tel Aviv, says:Over the last three years, we have seen quite impressive effects against certain cancers, including pancreatic cancer, which was thought to be incurable. Ten years ago, I would have thought that there was no chance of being able to vaccinate. Today, there is great hope.“.
However, the ongoing studies will already have to go through phase 3 and confirm their effectiveness. In addition, these vaccines will not be able to address all cancers, and will even have to be personalized for each patient in certain cases with still very high costs. The hope of transforming cancer into a chronic disease thanks to therapeutic vaccines without side effects is immense, but the road to such a future is still long.