Pharmaceutical behemoth Merck donated Moderna $200 million in 2016 to conduct research and create mRNA-based tailored cancer vaccines. It was a risky wager at the time because no vaccines using mRNA technology had yet been licenced.

A provision of the original agreement stated that Merck had the option to pay an undisclosed sum to co-develop and commercialise the shots with Moderna if the latter could successfully complete proof-of-concept tests of mRNA-based tailored cancer vaccines in people.

Since then, the COVID-19 vaccines have demonstrated the effectiveness of mRNA, and other more vaccines are currently being developed. And now, on the strength of that achievement, they are now going forward with cancer vaccinations.

In a phase 2 clinical trial for skin cancer, Merck is currently exercising its option on mRNA-4157, a tailored cancer vaccine. It is being investigated in conjunction with Keytruda, a humanised monoclonal antibody from Merck that is used to treat cancer.

Eliav Barr, head of global clinical development and CMO of Merck Research Laboratories, noted that this long-term partnership between Moderna's groundbreaking mRNA technology and Merck's immuno-oncology expertise has produced a revolutionary personalised vaccine approach.

The cancer vaccine developed by Moderna differs from most others in that it is intended to treat an existing illness rather than completely prevent it. In contrast to other shots, which are often mass-produced and given to the populace, it is also customised for each patient.

Moderna extracts a portion of the tumour from each patient to make the vaccine. Then, it uses genetic sequencing technology to find 'neoantigens,' or proteins, in the tissue. These proteins are specific to each person's tumour and are exclusively present on the surface of cancer cells.

Subsequently, Moderna use its mRNA technology to develop a vaccine that tells cells to produce up to 34 of the distinct neoantigens associated with the malignancy, which are then displayed to immune cells as possible targets. It is hoped that by doing this, the immune system will react negatively to the neoantigens, making it easier for it to recognise and destroy malignant cells. 157 patients with high-risk melanoma underwent surgical removal of their malignancies for Moderna's ongoing phase 2 study of mRNA-4157.

A dose of Keytruda was subsequently administered to some of the patients every three weeks for around a year or until their melanoma returned, followed by nine doses of a tailored cancer vaccine and Keytruda. For a whole year, the remaining patients received just one Keytruda treatment every three weeks.

The primary goal of the experiment is recurrence-free survival, and considering Merck's recent investment in the vaccine, it would seem logical to anticipate success.

Moderna President Stephen Hoge stated, 'With data on the [personalised cancer vaccine] expected this quarter, we continue to be enthused about the future and the impact mRNA can have as a new treatment paradigm in the management of cancer.'