ARTICLE

November 2003

‘Virtual Patients’ Could Help Expedite Vaccine Development

by Sandra I. Erwin

Computer models that simulate the human physiology could help create new vaccines to defeat potentially deadly biological agents, according to a small company that is trying to market the technology to the U.S. government.

In the pharmaceutical industry today, it takes 12 to 14 years and more than $800 million to bring a drug to the market, experts say. But in cases of unexpected attacks by a biological pathogen—man-made or naturally occurring—there is little time, let alone 12 years, to develop a therapy, said Michael French, president of Entelos Inc., a California-based biotech firm.

The company creates “virtual patients,” essentially computer simulations of patients who are suffering from certain diseases. The simulations developed so far, called PhysioLab models, include conditions from asthma, to obesity to rheumatoid arthritis. With data for numerous kinds of patients, the models can help determine, for example, why one person with a disease will respond to a certain medication while another, with the same symptoms, will not, French said.

“Our technology eliminates having to go down blind alleys and be able to look at complex systems associated with human immune response,” he said. When a company or government agency is trying to develop a new vaccine, for example, they would use the models to evaluate a person’s immunological response, ability to fight off infections and how specific pathogens affect the human system. If a previously unheard-of biological agent were released unexpectedly, this technology would help researchers figure out how to enhance the immune system and “mount a defense against something we haven’t characterized,” said French.

Entelos has been marketing this technology to the Defense Department and the National Institutes of Health, he said. Although he claims that the technology is useful as a research tool, French cautioned that the PhysioLab models should in no way be compared to live tests on humans or animals. A vaccine side effect on any given individual, for example, could not necessarily be predicted in these simulations. “I am not sure we can measure that or address the adverse affects that occur in patients,” he said. “Some people have different reactions” to vaccines. Virtual patient models, he added, “provide an environment for researchers to hypothesize.”

Entelos is a venture-capitalist financed company founded in 1996 by former missile-defense experts who worked on the Reagan administration’s Strategic Defense Initiative, known as Star Wars. After leaving SDI, they managed programs in the pharmaceutical industry. Over time, they realized that the pharmaceutical industry lacked an “objective way of really assessing the potential efficacy of compounds,” said French. “They set about creating models of human physiology to make those kinds of decisions—whether a potential drug was going to be effective.”

That evolved into the PhysioLab technology, which helped translate biology into mathematics by using special software.

“We found a top-down, behavior driven approach to creating a model,” said French. “We know the behaviors about humans. What we don’t know a lot about is the specific biology deep down inside the pathways in the human systems.”

It is unlikely that the Food and Drug Administration will, in the foreseeable future, approve drugs based on computer simulations, he said. “But that’s not what we are about here. We want to help the pharmaceutical industry make better decisions about what they take forward. ... When we make a prediction with our computers, we confirm that prediction through some kind of laboratory work. We are not trying to replace laboratory work or animal testing.”

To develop the sophisticated simulations, Entelos engineers used high-performance Hewlett Packard computers, French said.

Pharmaceutical clients like Pfizer, Johnson & Johnson and Bayer employ the models to test new drugs early in drug discovery, so that they can identify possible side effects, dosing regiments, and drop any duds before the time-consuming clinical trial phase. In recent months, Entelos has been meeting with officials from the National Institute of Allergy and Infectious Diseases. NIAID received $1.8 billion to develop bio-defenses.

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