This Week in HIV Research: Quitting Smoking Adds 5 Years to Life Expectancy, and Broadly Neutralizing Antibody Treatment Studied Further
This week, a study finds that quitting smoking could raise the life expectancy of people living with HIV by five years. Two other studies find that using a broadly neutralizing antibody has moderate success at suppressing viral loads within the first two months. Finally, "test and treat" may be the most cost effective HIV prevention option in Los Angeles, but pre-exposure prophylaxis is a close second. To beat HIV, you have to follow the science!
Quitting Smoking Increases Life Expectancy of People Living With HIV by Five Years
People living with HIV gain an additional five years of life if they quit smoking, a computer simulation published in The Journal of Infectious Diseases showed.
In the U.S., more than 40% of those in care for HIV smoke cigarettes, compared to 17% of the general population. Rates of cardiovascular disease, chronic obstructive pulmonary disease and various cancers are higher among smokers who live with HIV than among other smokers.
The simulation found that only 37% of men who enter HIV care at age 30 but continue to smoke are likely to reach the age of 70, while 65% of men who start HIV treatment at age 50 and never smoked will see their 70th birthday. Among women, the corresponding figures are 44% and 68%.
Even men and women who do not stop smoking until age 60 after beginning HIV treatment at age 50 can expect to live about two years longer than those who continue to inhale tobacco. "Smoking cessation should be a major priority in HIV care programs," study authors concluded.
Monotherapy With a Broadly Neutralizing Antibody Moderately Successful
Injections of a broadly neutralizing antibody (bNAb) controlled the viral loads of participants for four to five weeks in two related trials reported in the New England Journal of Medicine.
The specific bNAb used, VRC01, targets the HIV CD4-binding site. VRC01 was administered to 24 people living with HIV who stopped antiretroviral therapy. After four weeks, 38% and 80% of study participants in the AIDS Clinical Trial Group A5340 and National Institutes of Health (NIH) trials, respectively, still maintained an undetectable viral load, compared to 13% of historical controls in both trials. However, by the eighth week the virus had rebounded in most participants.
These small studies are only a first step in developing a functional cure that would free those living with HIV from having to take daily medications, said Pablo Tebas, M.D., one of the study's authors in a press release. He compared them to early monotherapy against HIV, theorizing that "it may take combinations of more potent antibodies to successfully control the virus."
Test-and-Treat Cheapest HIV Prevention Strategy in Los Angeles, But PrEP a Close Second
The lowest-cost way to prevent the acquisition of HIV is a test-and-treat (TT) strategy, according to a mathematical model of HIV incidence among men who have sex with men (MSM) in Los Angeles County that was published in Clinical Infectious Diseases.
TT means HIV testing efforts are expanded and people testing positive for the virus start to take antiretroviral medications right away. That prevention approach alone costs from US$19,302 per quality-adjusted life-year (QALY) gained. At US$27,863 and up per QALY saved, the price of pre-exposure prophylaxis (PrEP) is higher, but still well below the U.S. societal threshold of US$150,000 per QALY gained.
All HIV prevention approaches were compared to the status quo of HIV testing every 4.4 years and starting antiretroviral therapy at CD4 cell count levels of 500 cells/μL or fewer. Study authors acknowledge that these results may differ if other groups affected by HIV, such as MSM who also inject drugs or have sex with women, were included.