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Are ‘virtual patients’ the future of clinical trials?

Researchers have demonstrated that an in-silico approach, using virtual patient data, was able to replicate clinical trial results and investigate emergent findings related to the treatment of brain aneurysms.

The cost of clinical trials is increasing. Each clinical trial undergoes a series of steps. If the treatment is successful in one stage, the trial moves on to the next. Phase I focusses on the safety of a new drug on healthy volunteers and costs around $4 million. Phase II determines the efficacy of the treatment on patients and has an average cost of $13 million. Finally, phase III tests the clinical benefit of the drug at a defined dose. This costs about $20 million.

An in-silico trial is based on an individualised computer simulation that develops virtual patient populations from clinical databases. This approach not only reflects age, sex and ethnicity, but also simulates how a disease affects the human body. These reported interactions between anatomy, physiology and blood chemistry can then be used to model the impact of drug therapies or interventions.

The paramount advantage of in-silico trials is the substantial cost saving – it is estimated that they require just one third of the resources that clinical trials need, in terms of time to complete and operational prices. Therefore, drug governing authorities, such as the Food and Drug Administration (FDA), are working towards introducing evidence obtained from in-silico trials into the regulatory process of drug development.

An in-silico trial to treat intracranial aneurisms

An international group of researchers, led by the University of Leeds, recently investigated whether an in-silico trial could replicate the results from three clinical trials assessing the effectiveness of a device called a flow-diverter (FD).

An FD is a self-expanding stent-like device that is implanted into an aneurysm. Once in place, the FD directs blood along the blood vessel and reduces flow to the aneurysm. This initiates the natural formation of blood clots and eventually eradicates the aneurysm.

The team developed an in-silico flow diverter performance assessment (FD-PASS). The treatment of intracranial aneurysms was modelled in 164 virtual patients, with 82 distinct anatomies and FD stents. The FD-PASS predicted that 83% of the virtual patients with normal blood pressure could be successfully treated with an FD. In the three clinical trials, 87%, 75% and 77% of patients were treated, suggesting that the in-silico trial was, in fact, able to replicate the clinical trial results. Moreover, the scientists could adapt the FD-PASS to effectively investigate emergent findings, such as which patients had a higher risk of different stroke types.

Are virtual patients the future of drug development?

The FD-PASS approach demonstrated that in-silico methods can replicate findings of conventional clinical trials and perform virtual experiments that are near-impossible during human trials. The ability to rigorously analyse medical device or drug performance has the potential to minimise risks associated with the treatment and enhance the safety of participants. Further noteworthy advantages of the virtual approach include cost savings, shorter times to perform procedures, the ability to analyse unique patient characteristics and the vast scalability without delays.

Professor Alex Frangi, from the University of Leeds, said:

“The results demonstrate the huge potential of in-silico trials. Conventional trials can easily take five to eight years, from their design to completion. In-silico trials could reduce this period to less than six months in some circumstances, making knowledge and therapeutic technologies safer and more promptly available to clinicians and patients.”

Image credit: FreePik user14636459

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