Genomic Medicine in an Expanding World

What is genomic medicine?

Genomic medicine uses DNA, the genetic code in each cell, to better tailor treatments to an individual. It allows for treatments to be more targeted (such as using a particular medicine for a certain type of breast cancer compared to another) whilst also allowing pre-existing therapies to be repurposed when a new target is identified. These novel targets may be a completely different type of disease, such as leprosy and multiple myeloma which can both be treated with thalidomide in certain cases.

The use of genomics in medicine has also helped to find similarities between gene mutations, which often allows treatments to be purposed for multiple diagnoses. HER2 gene mutations are shared between ovarian, bladder, and pancreatic cancers, for example, so once identified in a patient, treatments can be chosen based on the gene mutation found. Likewise, if a tumour is identified to not have that gene mutation, unnecessary therapies will not be given to a patient. This is because a more suitable treatment can hopefully be identified.

In an expanding world?

When we talk of an expanding world, we mean specifically in relation to the human population. Even with a slowdown in the annual growth rate of the world’s population, the latter is still increasing. This is currently at 7.7 billion people, with predictions putting the world population at nearly 10 billion in 2050.

Why would genomics medicine be useful as the world’s population expands? There are clear benefits and applications now, and these will only become clearer – and more useful – as the population grows. With a larger population, there will be more instances of a rare disease being diagnosed in a patient. A rare disease is defined by the EU as affecting less than 5 in 10,000 people. In the UK, 1 in 17 people will be affected by a rare disease at some point in their lives, with 80% of these diseases having a genetic component.

So, what are the applications for genomics in medicine? How much more use will there be with a larger population? The value of using genomics in medicine becomes steadily more apparent as populations increase. As biobank cohorts grow and are followed up over time, the value of genomic information that can be obtained will increase too. Diseases with many subtypes such as cancers can be further broken down into the genomic signatures, enabling more targeted therapies that should be able to be deployed in a much more directed fashion.

Benefits to genomic medicine

So, what is the benefit of genomic medicine in an expanding world? There are two main areas of benefit. The first relates to the simple fact that we have more genomic information to inform treatments, while the second relates to the use of that data.

Much like how the reference human genome was predominately created with white Europeans in mind, with a number of variants that are common in other populations not captured, using genomics and capturing a wide range of ‘normal’ or ‘abnormal’ genomes is key. Using genomics in medicine more often ensures that any drugs made from data collected have representative samples of the wider population. Clinical trials, for this reason, aim to have a mixture of ages and genders.

More genomic information also allows for therapies to be more targeted. If there is a HER2 mutation in a tumour, a certain therapy can be used. Conversely, if a HER2 mutation is not present, certain therapies could be avoided as it is known they will not work on those tumours. This targeting leads to how drugs can be repurposed for new indications.

Drugs that are already on the market and deemed as safe by regulatory bodies often have more potential therapeutic applications than just the one they have originally been created for. Finding out what biological pathways a treatment affects, or what symptoms it can alleviate, enables one drug to be used for multiple diseases or infections. For example, drugs such as aspirin can be repurposed from treating pain and inflammation to treating antiplatelet diseases. The fact that these treatments are not only backed by genomic evidence showing their benefits but also repurposing existing drugs, means that the therapies should make it to market at a faster rate. Clinical trials and safety tests have already been conducted when the drug first came to market. This means that only drug efficacy tests on the proposed disease will be required.