HIV-TRePS just got even better

Latest models for predicting response to HIV therapy the most accurate to date.

LONDON, UK Tuesday 16th February 2016. The RDI's free online HIV Treatment Response Prediction System (HIV-TRePS) has been updated with the most accurate models to date. Two new sets of models have been developed to predict virological response to any combination of HIV drugs for patients failing on their current therapy.

The first set of models was trained using the treatment history, viral load and CD4 count from almost 30,000 patients. Critically they do not need the results of a resistance test for their predictions, and so are well-suited for use in low- middle-income countries where such tests are not generally affordable. These 'global' models achieved accuracy* of 0.82 in independent testing. Their performance was compared with that of 'local' models trained using data from South African patients only for patients in that country and the global models were found to be superior in terms of their ability to identify alternative combinations of locally-available drugs that were predicted to be effective.

"Use of these latest models has the potential to reduce virological failure and improve patient outcomes, particularly in resource-limited settings", commented Dr Andrew Revell, Executive Director of the RDI. "The models provide clinicians with a practical tool to support optimised treatment decision-making, even in the absence of resistance tests and where expertise may be lacking in the context of a public health approach to antiretroviral roll-out and management."

The second set of models was developed using 15,130 cases where a genotypic resistance test was obtained while the patient's therapy was failing, to help inform the selection of the next regimen. These models achieved accuracy of 0.84 in independent testing. The models were significantly more accurate predictors of response than the results of the resistance tests, interpreted using the most commonly used interpretation systems, such as Stanford HIVdb, which achieved accuracy scores of 0.55-0.58.

"Once again the RDI models have substantially out-performed genotyping with rules-based interpretation as a means of predicting treatment outcomes" commented Dr Brendan Larder, Scientific Chair. "The results, particularly those from our models that do not require a resistance test, add to the substantial body of evidence suggesting that, where resources are scarce, they would be better allocated to expanding access to treatment rather than resistance testing".

The RDI is an independent, not-for-profit research group set-up in 2002 with the mission to improve the clinical management of HIV infection through the application of bioinformatics to HIV drug resistance and treatment outcome data. Over the thirteen years since its inception, the RDI has worked with many of the leading clinicians and scientists in the world to develop the world's largest database of HIV drug resistance and treatment outcome data, containing information from approximately 180,000 patients in more than 30 countries.

HIV-TRePS is an experimental system intended for research use only. The predictions of the system are not intended to replace professional medical care and attention by a qualified medical practitioner and consequently the RDI does not accept any responsibility for the selection of drugs, the patient's response to treatment or differences between the predictions and patients' responses.

This project has been funded in whole or in part with federal funds from the National Cancer Institute, National Institutes of Health, under Contract No. HHSN261200800001E. This research was supported by the National Institute of Allergy and Infectious Diseases. The content of this publication does not necessarily reflect the views or policies of the Department of Health and Human Services, nor does mention of trade names, commercial products, or organizations imply endorsement by the U.S. Government.

More information can be found at:
For further information contact:
Andrew Revell (Executive Director, RDI) on +44 207 226 7314, +44 7067 126498 (mobile) or

The following are available for interview on request, arranged through Andrew Revell above:
Dr Brendan Larder: Scientific Chairman of the RDI, London, UK
Dr Andrew Revell: Executive Director, RDI, London, UK.

Date published: 16th February 2016


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