A study involving virtual rather than real patients was as effective as traditional clinical trials in evaluating a medical device used to treat brain aneurysms, according to new research.
The findings are proof of concept for what are called in-silico trials, where instead of recruiting people to a real-life clinical trial, researchers build digital simulations of patient groups, loosely akin to the way virtual populations are built in The Sims computer game.
In-silico trials could revolutionize the way clinical trials are conducted, reducing the time and costs of getting new medical devices and medicines developed, while reducing human and animal harm in testing.
Effect of a flow diverter on blood flow around a brain aneurysm. Once the flow diverter is in place, it reduces blood flow to the aneurysm, allowing it to heal.
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The virtual patient populations are developed from clinical databases to reflect age, sex and ethnicity but they also simulate the way disease affects the human body: for example, the interactions between anatomy, physics, physiology, and blood biochemistry. Those simulations are then used to model the impact of therapies and interventions.
The international research, led by the University of Leeds and reported in Nature Communications, investigated whether an in-silico trial could replicate the results of three, real-life clinical trials that assessed the effectiveness of a device called a flow diverter, used in the treatment of brain aneurysms, a disease where the wall of a blood vessel weakens and begins to bulge.
A flow diverter is a small, flexible mesh tube which is guided to the site of the aneurysm by a doctor using a catheter. Once in place, the flow diverter directs blood along the blood vessel and reduces flow into the aneurysm, initiating a clotting process that eventually cuts the aneurysm off from blood circulation, thus healing it.
To establish their proof of concept, the researchers had to see if the results from their in-silico study agreed with the results from three previous major clinical trials into the effectiveness of flow diverters.
The researchers built a virtual population using real patient data drawn from clinical databases, ensuring that the anonymized virtual patients closely resembled the patients used in real flow diverter clinical trials in terms of age, sex and aneurysm characteristics.
The researchers then built a computational model that analyzed how the implanted device would affect blood flow in each of the virtual patients. They were able to study different physiological conditions for each patient, such as normal and high blood pressure, and perform analyses on patient sub-groups, such as those with large aneurysms or aneurysms with a branch vessel.
The traditional clinical trials (called PUFS, PREMIER and ASPIRe) had 109, 141 and 207 patients, respectively. Around half the cases in the traditional trials had high blood pressure.
The results of the in-silico trial predicted that 82.9% of the virtual patients with normal blood pressure would be successfully treated with a flow diverter. In the traditional clinical trials, the number of people who were successfully treated was 86.8%, 74.8% and 76.8%, respectively, thus showing that the in-silico trial replicated the traditional clinical trials results.