AIDS 2012: Other Treatment Studies

Several studies presented new information on other aspects of HIV treatment.

Maraviroc Plus Atazanavir/Ritonavir

The CCR5 inhibitor maraviroc was initially studied in combination with two other active drugs. However, because some boosted protease inhibitors increase the drug levels of maraviroc so that only half the recommended dose is needed, some researchers used this as the basis for a new combination.

Unfortunately, the percentage of people with undetectable viral load looked worse compared to a three-drug combination (68% vs 82% with maraviroc plus tenofovir/FTC). New studies are now using darunavir/ritonavir with maraviroc to see if this can be improved.

Gallstones With Atazanavir

A French study reported that atazanavir was associated with development of gallstones.

Although this is the first report, the link seemed fairly convincing as analysis of the stones showed that they largely contained atazanavir. However many of these cases generally had other pre-existing liver complications, including hepatitis C.

Atazanavir has also been reported to cause kidney stones.

Raltegravir Good at Five Years

Several studies reported longer-term (five year) results using raltegravir. Of note, after four years raltegravir became significantly better than efavirenz (both also used with tenofovir/FTC). This was largely driven by more people stopping efavirenz due to side effects.

A study at a workshop prior to the main conference also reported that markers of muscle toxicity were higher in people using raltegravir (or reporting recent exercise) compared to people not using raltegravir.

The changes were all generally mild and no cases of serious muscle toxicity were reported. However, a more serious form of muscle toxicity called rhabdomyolysis has been reported with raltegravir, so this might be an early signal to watch.

Why Does Male Circumcision Protect From HIV?

One study proposed a new mechanism for why medical male circumcision reduces the risk for a man to catch HIV.

Previously this was thought to be due to a thinner keratin layer (of sort of tissue padding) in the inner foreskin.

The new study suggested that the route for infection is through the sensitive membrane of the head of the  penis. Uncircumcised men were found to have a higher percentage of cells nearer to the skin surface, that HIV needs to find for infection to take hold.

References

Unless stated otherwise, all references are to the Programme and Abstracts of the 19th International AIDS Society World AIDS Conference, 22–25 July 2012, Washington DC. http://www.aids2012.org.

1. Mills A et al. Once-daily maraviroc in combination with ritonavir-boosted atazanavir in treatment-naive patients infected with CCR5-tropic HIV-1 (study A4001078): 96-week results. Oral abstract TUAB0102. http://pag.aids2012.org/Abstracts.aspx?SID=202&AID=16304
2. Poinsignon Y et al. Complicated atazanavir-associated cholelithiasis: a report of eight documented cases among 11 cases. Poster abstract MOPE099. http://pag.aids2012.org/Abstracts.aspx?AID=6375
3. Rockstroh J et al. Long-term safety and efficacy of raltegravir (RAL)-based versus efavirenz (EFV)-based combination therapy in treatment-naive HIV-1-infected patients: final 5-year results. Poster abstract LBPE19. http://pag.aids2012.org/abstracts.aspx?aid=21410
4. Eron J et al. Final five-year results of the BENCHMRK studies: sustained antiretroviral effect of raltegravir and exploratory analysis of late outcomes based on early virologic response. Poster abstract TUPE025. http://pag.aids2012.org/abstracts.aspx?aid=12576
5. Lee FJ et al. Skeletal muscle toxicity associated with raltegravir-based combination antiretroviral therapy in HIV-infected adults. 14th IWCADR, 19-21 July 2012, Washington. Oral abstract 015. Antiviral therapy 2012; 17 Suppl 2:A13. See: http://i-base.info/htb/19821
6. Dinh M et al. HIV-1 female-to-male sexual transmission: evaluation of circumcised and uncircumcised penile tissue. Oral abstract MOLBA03. http://pag.aids2012.org/abstracts.aspx?aid=21033; http://i-base.info/htb/19837