Breaking news: Study predicts 'wave' of HIV resistance;
SF official says no cause for alarm
by Seth Hemmelgarn
A study released Thursday morning predicts a "wave" of HIV drug resistant strains "will emerge over the next five years in San Francisco due to transmission from untreated individuals." But it's questionable how much cause for alarm there really is.
The results of the study, from researchers at the UCLA and UCSF and to be published January 14 on the Web site of the journal Science, "also have implications for resource-constrained countries where first-line regimens" are based on non-nucleoside reverse transcriptase inhibitors, or NNRTIs, a type of antiretroviral drug.
"If the resistant strains we have identified in our analyses evolve in these countries, they could significantly compromise HIV treatment programs. Consequently, currently circulating NNRTI-resistant strains in San Francisco pose a great and immediate threat to global public health," the study said.
But Dr. Grant Colfax, the city's HIV prevention director, told the Bay Area Reporter, "At this point, HIV drug resistance is not a public health crisis. The sky is not falling."
Colfax said that the study shouldn't change clinical practice or public health policy at this point.
"In San Francisco, as more people have gone on treatment, we've seen dramatic drops in morbidity and mortality, and we're starting to see a decline in newly reported HIV infections," Colfax said.
He continued, "Our treatment options are better than ever before, and while resistance is an ongoing concern, and always will be, we also need to be clear that the benefits of treatment are high and that the new guidelines regarding treatment have swung toward recommending treatment earlier."
Colfax said it's already known that NNRTI resistance "emerges very rapidly and can be a significant problem. That's nothing new here."
However, he said that hopefully data from the study could be used to get therapeutic options available in San Francisco "upscaled for developing countries."
Asked about the study being alarmist or unbelievable, Sally Blower, director of UCLA's Center for Biomedical Modeling and a member of the UCLA AIDS Institute, told the B.A.R. that she and the others were publishing a paper in "one of the best" scientific journals in the world.
Blower said the report is a "very thorough ... very detailed analysis based on lots of details and lots of calculations" that has been "thoroughly peer-reviewed."
"I'm very confident that it's correct," she said.
A UCLA press release announcing the study contained a particularly interesting quote from a co-first author on the study.
In the release, Justin T. Okano said, "Our model showed that what is going on in San Francisco is very complicated – but in a nutshell, it is due to the bug, the drugs, and sex." he said.
Okana told the B.A.R. he was summing up the parameters for their model, which related to the virus, treatment regimens, and sexual behavior.
Blower said the quote was "definitely not intended to be" homophobic.
According to UCLA, the model can be used to predict drug resistance in any setting where individuals are treated for HIV infection. The researchers found that the drug-resistant strains emerging in San Francisco are "very likely" to appear in many African countries, where treatment is just beginning, according to the university's release.
The researchers developed a complex network model that tracks the transmission of multiple strains of HIV. They began the study by using their model to analyze data from San Francisco, and they modeled the evolution of drug-resistant strains over the past 20 years and predicted their spread over the next five years, according to co-first author Robert Smith, who was a postdoctoral fellow in Blower's lab when the research was conducted.
"What was very disturbing was we found that some of the drug-resistant strains were increasing," said Smith, now an assistant professor in the department of mathematics and statistics at the University of Ottawa, in the UCLA statement.
Co-author Dr. James Kahn, professor of clinical medicine at the UCSF Positive Health Program at San Francisco General Hospital, told the B.A.R., "I think that rather than be alarmist in nature, what our study does is it provides an opportunity for policy planners to make decisions on how to be prepared for the future."
He said an example of what the researchers hope their study will do is "help the policy deciders not to reduce support" for the AIDS Drug Assistance Program, which helps people with AIDS get access to medications. "That turns out to be critical, and as new drugs get developed we want to make sure they're covered on ADAP."
Kahn said, "This is probably the most comprehensive model that's been developed ... to study an infectious disease of any kind and our model can be adapted to other infectious disease situations, like for hepatitis C or hepatitis B, and tuberculosis."
More information can be found on Blower's site, at www.semel.ucla.edu/biomedicalmodeling.