Virco first to use artificial intelligence to unravel the mystery of HIV drug resistance

October 25, 2000

Neural networks make Virco resistance testing even more accurate

GLASGOW, SCOTLAND, October 26, 2000 - Data presented today at the 5th International Congress on Drug Therapy in HIV Infection for the first time revealed the mutations in the genetic code of HIV that make the virus resistant to the HIV drug, d4T (stavudine). The mutations were identified using an artificial intelligence technique known as neural networks. This technique is now being applied to fine-tune Virco's VirtualPhenotype™ test, making it the most sophisticated and accurate system for predicting drug resistance from the genetic "fingerprint" of a patient's HIV.

While resistance to d4T has been observed in the clinic, its genetic basis was poorly understood. The neural networks technique identified a group of 26 mutations in the HIV genetic code that, in different combinations, cause resistance to this drug. The data indicate that the genetic cause of resistance to d4T is more complex than was previously thought and than for other drugs in the same class. A previous model of d4T resistance, based on nine mutations, published by Stanford University and used by some clinicians to interpret genotypic information, was also tested and proved inadequate for predicting resistance to d4T.

"This is a very important development," said Dr. Stefano Vella, President of the International AIDS Society. "Firstly, these data indicate that neural networks could prove extremely valuable in furthering our understanding of resistance to HIV drugs and improving our ability to manage resistance for the benefit of our patients. It is also a fascinating example of how we are using advances in a variety of different disciplines and applying them, in an integrated way, to accelerate progress in the HIV field."

Historically, HIV drug resistance testing has been approached in two ways:
 The phenotype - a direct measurement of the effect of drugs on the growth of virus derived from a patient's blood sample
 The genotype - the genetic code of the patient's HIV is read and any mutations identified (an indirect assessment of HIV drug resistance)


Genotyping is the quicker and more commonly used approach. The challenge is then to interpret the information. There are over 100 known individual mutations involved in HIV resistance, which interacts in highly complex ways, making this interpretation extremely difficult.

In this study, neural networks were fed with both genotypic and phenotypic information from 2,098 patient samples and this information was used by the neural networks software to generate large numbers of simultaneous equations: in essence trying different combinations of mutations to try to 'explain' the phenotypic changes in resistance to d4T. The neural network runs over and over again, learning from each run, to improve on its predictive accuracy. The model constructed by the neural network, involving 26 mutations, was then applied to the genotypes from 188 test samples and was able to predict their phenotypic resistance with an accuracy of 80%.

"The causation of HIV drug resistance is extremely complicated," commented Dr. Brendan Larder, Chief Scientific Officer at Virco and presenter of the study. "This approach harnesses enormous computing power to unravel the complex relationship between genetic changes and the resistant behaviour of the virus. The use of neural networks is helping to make the Virtual Phenotype the most sophisticated and accurate predictor of resistance from the genotype."

In addition to refining our understanding of the interactions between mutations and the genetic basis of resistance to current drugs, neural networks are being used by Virco to identify new resistance mutations and combinations that cause resistance to new HIV drugs.
-end-
Company Background
Virco is a multinational biotechnology company with operating subsidiaries in the United States, Belgium, The United Kingdom and Ireland. It applies the most advanced technologies in molecular biology, automation, ultra high-throughput screening and electronic data processing to the diagnosis and management of HIV, other infectious diseases and cancer. Virco is the only company to provide genotyping, phenotyping and the new, unique VirtualPhenotype. The company believes it provides the most sophisticated and comprehensive portfolio of phenotyping and genotyping decision support tools for physicians treating HIV infected patients.

Virco sells its testing services via Laboratory Corporation of America Holdings (LabCorp), SRL in Japan, as well as directly to HIV/AIDS centers in Europe, Canada and Australia. Virco has also recently announced a two-year agreement with Gilead for the promotion of Virco Resistance Monitoring Services to US HIV prescribers by the Gilead sales force.

For further information, please visit Virco's website: http://www.vircolab.com. .

U.S. Contact: Peter Vigliarolo, Cooney/Waters; Tel: 212/886-2200 Virco: Dr. Andrew Revell; Tel: + 44 7967 126498 or at the Virco exhibition

Cooney Waters Group, Inc.

Related HIV Articles from Brightsurf:

BEAT-HIV Delaney collaboratory issues recommendations measuring persistent HIV reservoirs
Spearheaded by Wistar scientists, top worldwide HIV researchers from the BEAT-HIV Martin Delaney Collaboratory to Cure HIV-1 Infection by Combination Immunotherapy (BEAT-HIV Collaboratory) compiled the first comprehensive set of recommendations on how to best measure the size of persistent HIV reservoirs during cure-directed clinical studies.

The Lancet HIV: Study suggests a second patient has been cured of HIV
A study of the second HIV patient to undergo successful stem cell transplantation from donors with a HIV-resistant gene, finds that there was no active viral infection in the patient's blood 30 months after they stopped anti-retroviral therapy, according to a case report published in The Lancet HIV journal and presented at CROI (Conference on Retroviruses and Opportunistic Infections).

Children with HIV score below HIV-negative peers in cognitive, motor function tests
Children who acquired HIV in utero or during birth or breastfeeding did not perform as well as their peers who do not have HIV on tests measuring cognitive ability, motor function and attention, according to a report published online today in Clinical Infectious Diseases.

Efforts to end the HIV epidemic must not ignore people already living with HIV
Efforts to prevent new HIV transmissions in the US must be accompanied by addressing HIV-associated comorbidities to improve the health of people already living with HIV, NIH experts assert in the third of a series of JAMA commentaries.

The Lancet HIV: Severe anti-LGBT legislations associated with lower testing and awareness of HIV in African countries
This first systematic review to investigate HIV testing, treatment and viral suppression in men who have sex with men in Africa finds that among the most recent studies (conducted after 2011) only half of men have been tested for HIV in the past 12 months.

The Lancet HIV: Tenfold increase in number of adolescents on HIV treatment in South Africa since 2010, but many still untreated
A new study of more than 700,000 one to 19-year olds being treated for HIV infection suggests a ten-fold increase in the number of adolescents aged 15 to 19 receiving HIV treatment in South Africa, according to results published in The Lancet HIV journal.

Starting HIV treatment in ERs may be key to ending HIV spread worldwide
In a follow-up study conducted in South Africa, Johns Hopkins Medicine researchers say they have evidence that hospital emergency departments (EDs) worldwide may be key strategic settings for curbing the spread of HIV infections in hard-to-reach populations if the EDs jump-start treatment and case management as well as diagnosis of the disease.

NIH HIV experts prioritize research to achieve sustained ART-free HIV remission
Achieving sustained remission of HIV without life-long antiretroviral therapy (ART) is a top HIV research priority, according to a new commentary in JAMA by experts at the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health.

The Lancet HIV: PrEP implementation is associated with a rapid decline in new HIV infections
Study from Australia is the first to evaluate a population-level roll-out of pre-exposure prophylaxis (PrEP) in men who have sex with men.

Researchers date 'hibernating' HIV strains, advancing BC's leadership in HIV cure research
Researchers have developed a novel way for dating 'hibernating' HIV strains, in an advancement for HIV cure research.

Read More: HIV News and HIV Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.