Aspirin Regimen Reduces HIV Target Cells, Could Cut HIV Transmission Risk

A daily regimen of low-dose aspirin might be a viable HIV-prevention tool in high-risk populations, particularly where other prevention measures are not widely available, according to a small 6-week study in Kenya. If the results are confirmed in a larger study, they could enable women to lower—but not eliminate—their chances of contracting HIV.

For the study, a team of Canadian investigators wanted to build upon previous work showing that inflammation in the female vaginal tract correlates with an increased risk of HIV infection because the inflammation brings highly-activated HIV target cells to the tract. The investigators posited that they could limit the risk of HIV transmission by limiting the number of these HIV target cells. They could limit the number of target cells, they theorized, by putting women on an anti-inflammatory regimen.

The team enrolled 91 women in Nairobi, Kenya, who were at low risk of HIV. Of the 76 women who completed the study, half (37) were given a 6-week regimen of low-dose (81 mg) aspirin. The other 39 were given a 6-week course of hydroxychloroquine (HCQ) (200 mg).

Both regimens had some impact; however, the major finding was that aspirin dose was associated with 35% and 28% reductions in 2 types of highly-activated HIV target cells studied, CD4+CCR5+ and Th17. In the case of HCQ, the reduction in HIV target cells was primarily in the blood, but the drug had less of an impact in the genital tract.

Corresponding author Keith R. Fowke, PhD, a professor in the department of medical microbiology and infectious diseases at the University of Manitoba, said the reductions were a pleasant surprise. For the purposes of the study, the investigators compared levels of HIV target cells in the study participants to those of highly exposed seronegative (HESN) women.

“The [aspirin]-induced levels approached but were still statistically higher than the HESN genital target cell levels,” he told MD Magazine®. “So, I feel that while the [aspirin] results are encouraging, it may be possible to reduce the target cells levels even further either with a different dose of [aspirin] or a longer treatment time.”

Fowke said the Canadian Institutes for Health Research are funding a follow-up study to test that hypothesis. If the findings hold up, he said he does see an aspirin regimen as being practical for anyone at risk of HIV.

“It would be used by those at high risk and preferably used in conjunction with other prevention approaches, such as pre-exposure prophylaxis (PrEP),” he said.

Fowke also noted that aspirin has other advantages, in addition to being affordable.

“When consulting with women of the community prior to the start of the study, they expressed significant reservations about using PrEP drugs as they were highly stigmatizing,” he said. “We have to do a better job trying to reduce the stigma women feel but we also have to provide alternatives.”

However, insofar as stigma exists around PrEP, Fowke said aspirin is so common as to be essentially stigma-free.

“If we can demonstrate that [aspirin] has benefit in HIV prevention, the exciting thing for me is that it is already in every little community kiosk or store throughout the world,” he said. “We just need to provide the solid scientific evidence that it is beneficial, council people on who should take it for HIV prevention, and people could affordably access it.”

The study, “Using safe, affordable and accessible non-steroidal anti-inflammatory drugs to reduce the number of HIV target cells in the blood and at the female genital tract,” was published in the Journal of the International AIDS Society.