Personalised mRNA Vaccines (Health, Diseases and Biotechnology)
Personalised mRNA Vaccines (Health, Diseases and Biotechnology)
Why In News:
Moderna and Merck recently announced that their personalized mRNA cancer vaccine intismeran autogene met its primary and key secondary endpoints in a Phase 3 trial involving patients with high-risk melanoma.
What is Melanoma?
Melanoma is an aggressive form of skin cancer that develops from melanocytes, the cells responsible for producing the pigment melanin.
Although it accounts for a relatively small share of skin-cancer cases, melanoma causes a disproportionately large share of skin-cancer deaths because of its ability to spread to other organs.
How Does a Personalised Cancer Vaccine Work?
Identify mutations: A sample of the patient's tumour is genetically sequenced to identify mutations that are unique to the cancer cells.
Identify neoantigens: These mutations may produce abnormal proteins called neoantigens, which can serve as specific targets for the immune system.
Design the vaccine: An individualised mRNA vaccine is created containing instructions to produce these tumour-specific targets.
Activate immunity: The mRNA temporarily instructs cells to produce the selected targets, helping the immune system recognise them as abnormal.
Attack cancer cells: T cells learn to recognise the neoantigens and target cancer cells carrying them, while largely sparing healthy cells.
Key Facts for Prelims
1. mRNA Technology
Messenger RNA (mRNA) carries temporary genetic instructions from DNA to cellular machinery for producing proteins.
mRNA vaccines use this mechanism to trigger an immune response without permanently altering the recipient's DNA.
In personalised cancer vaccines, mRNA can be designed to encode tumour-specific antigens, allowing the immune system to recognise cancer cells more precisely.
2. Neoantigens and Personalised Cancer Vaccines
Neoantigens are novel abnormal antigens arising from tumour-specific genetic mutations and are generally absent from healthy cells.
Their tumour-specific nature makes them attractive targets for personalised immunotherapy, with each patient's vaccine potentially containing a different combination of neoantigens.
3. Immune Checkpoint Inhibitors
Pembrolizumab (Keytruda) is a drug that helps the immune system fight cancer more effectively.
Cancer cells can use the PD-1 pathway to weaken or “switch off” T cells; pembrolizumab blocks this pathway, allowing T cells to remain active.
When combined with a personalised mRNA vaccine, the vaccine helps T cells identify the cancer cells, while pembrolizumab helps them continue attacking those cells.