The US-based biotechnology company Moderna, whose name we often heard during the pandemic, came out with some news that inspired hope in millions.
Moderna announced that the 'personalised cancer vaccine' developed with the US-based pharmaceutical company Merck (MSD), when used with an immunotherapy drug, reduces the recurrence rate of the disease and the risk of death in melanoma patients, one of the most dangerous types of skin cancer, by 44% compared to drug use alone. It was stated that the cancer vaccine, developed 'specially' for each patient with the mRNA technology used by Moderna in the coronavirus vaccine, uses genetic code fragments obtained from the tumours of cancer patients and 'trains' the body to fight against cancer.
How does it work?
To develop the vaccine, scientists first analysed DNA taken from each patient's cancerous cells through biopsy and identified mutations called neoepitopes in tumour cells. They then identified a few dozen of these neoepitopes that they thought would generate the strongest immune response in a patient, and added 'messenger RNA', or mRNA technology, the molecule that carries the genetic code of these neoepitopes and a cell's instructions to produce proteins, to the vaccine. It was discovered that when mRNA enters the body, the patient's cells are instructed to produce neoepitopes, which triggers an immune response that allows cancer cells to be better targeted and destroyed.
Tthe testing process
The vaccine was tested on a total of 157 patients with stage 3 and 4 melanoma, the most lethal type, in combination with a course of Keytruda, an immunotherapy drug developed by Merck that releases barriers in the immune system to fight cancer, in nine doses every three weeks. By comparing this group of patients, who received the treatment after their tumours had been surgically removed, with a control group of high-risk melanoma patients who had undergone surgery but only received the immunotherapy Keytruda treatment, it was discovered that the new treatment achieved 44% success rate.
Stating that the results are extremely 'encouraging' for cancer treatment, Stéphane Bancel, CEO of Moderna, said, 'mRNA has been transformative for COVID-19, and now, for the first time ever, we have demonstrated the potential for mRNA to have an impact on outcomes in a randomized clinical trial in melanoma.' Bancel announced plans to test the vaccine on other cancer types with the purpose of offering personalised cancer treatments to cancer patients.
Obstacles on the road to a cancer vaccine
According to Elias Sayour, a neurosurgeon at the University of Florida who works on cancer vaccines at the RNA Engineering Laboratory, it is theoretically possible for an mRNA manufacturer to produce a personalised cancer vaccine in as little as four weeks. In practice, however, Sayour says, much more mutation detection algorithms and much more testing are needed before mRNA vaccines are ready for routine use in cancers.
Sayour underlines that mRNA will probably work better for some cancers than others. Stating that not all cancers are immunogenic, that is, they do not trigger an immune response, Sayour states that it is difficult to know which protein should be encoded in an mRNA vaccine without an immune response.
On the other hand, according to Henry Wang, a professor of chemical engineering at the University of Michigan who works on vaccine production, the production of the vaccine is a much bigger problem than Sayour emphasises. Producing an mRNA vaccine for cancer is quite different from producing an mRNA vaccine for Covid-19. This raises questions such as how to scale up the production of a drug that requires such careful and detailed customisation, and how to manage the process.
Of course, there is also the financial dimension. Although it raises hope that humanity can prevail in the war against cancer, it seems that Moderna's new vaccine may not be accessible to everyone. Similar cancer vaccines currently cost about 100 thousand dollars per dose.