Is customized medicine the future of disease prevention?
We’re all unique, and we all have unique medical needs. What might work for one person won’t work for somebody else. The reasons for this are very complicated — diet, lifestyle, and genetics all play a part. Now the science of precision medicine is helping doctors to make treatments more effective for everybody. By customizing them for different patients, we can all get the exact treatment we need. Here’s a look at what the future of medicine, disease prevention, and longevity might look like.
What is precision medicine?
Precision medicine, aka personalized medicine, doesn’t mean each person gets unique treatment. Not yet. Instead, doctors start with a general treatment plan and then optimize it for their patients.
In some ways, doctors have always done this. If a patient needs to lose weight but isn’t mobile enough to exercise, they might prescribe an appetite suppressant to help. If a patient doesn’t respond to one chemotherapy drug, they will try another, and so on.
Precision medicine takes this to another level by also using genetic information to tailor a treatment plan. For instance Tamoxifen is a common breast cancer drug, but up to 10% of people have a genetic resistance to it. That means it won’t work for them, and another treatment is needed. By testing patients for this gene, doctors can save a lot of time that would otherwise have been lost on a treatment that won’t work.
What genetic information does precision medicine use?
There are all kinds of different tests doctors can run, depending on the disease and treatment a patient is facing. We’re already familiar with several of them, like blood tests for high cholesterol or diabetes, and antigen tests such as for COVID-19. Precision medicine looks at even more information to create a fuller picture of a patient’s specific needs.
Some genes people carry can make them more likely to develop particular diseases or cancers. There are genetic tests available now that can look for many different conditions. These include breast and ovarian cancer, celiac disease, Parkinson’s, psoriasis, and even obesity and mental health disorders. These tests have become so fast and cheap in recent years that you can purchase them privately from companies like 23andMe for less than $100.
Pharmacogenetics is the study of how people respond to different drugs. Some people are genetically predisposed to be more or less susceptible to some medicines based on their genetics. The same gene that causes Tamoxifen resistance can also cause resistance to common opioids. That’s important to know, because otherwise these patients won’t get adequate pain management. They may even be falsely accused of drug-seeking and refused treatment.
Another example is the blood-thinning medication warfarin. Up to 35% of white people have a genetic variant that prevents them from fully metabolizing warfarin. That can lead to a significant buildup of the medication over time, causing life-threatening side effects. As a result, doctors now take racial background into account when prescribing warfarin.
How precision medicine uses genetic information to improve treatments
With better understanding of a patient’s needs, doctors can improve treatment plans and outcomes. The most advanced precision medicine techniques can even alter a patient’s DNA to help their bodies fight diseases.
CRISPRs (Clustered Regularly Interspaced Short Palindromic Repeats) are a genetic memory bank of past diseases. They were discovered in bacteria, as part of the defence mechanism against viruses. Once the bacteria has fought off a virus, it cuts up the virus’s DNA and stores it in its own genome. There it creates a library of how to fight off that virus again in the future.
For human medicine, the most exciting thing about the discovery of CRISPRs was their ability to cut and edit DNA. By changing its sequence, scientists could create a tool that can repair damage to human DNA.
In March 2020, this technology was used in human trials for the first time. It replaced a faulty genetic sequence that caused the inherited disease Leber congenital amaurosis 10 (LCA10). This disease causes blindness from birth and has no other known treatment. If it works, it means CRISPR will have created a one-time, permanent cure. The trial will end in 2024.
What does the future of precision medicine look like?
The use of artificial intelligence (AI) has helped to increase the rate at which we develop new precision medicines. In the past, it was almost impossible to review the massive amounts of data that we can get from genetic studies. Now, supercomputers can chart gene anomalies and generate results in days, not decades.
In January 2022, researchers at Massachusetts General Hospital and the National Cancer Research Centre used machine learning to find new ways of repairing DNA damage. They hope this will lead to new and more effective cancer treatments. One day, precision medicine could help us identify and repair genetic causes of common diseases before they ever strike.