The AIDS Beacon™

Scientists and researchers from around the globe met last week for the 17th Conference on Retroviruses and Opportunistic Infections (CROI), a four-day conference presenting the latest research about prevention, treatment, and insight into HIV/AIDS and its complications.

Topics ran the gamut from novel therapies to public health strategies aimed at the global pandemic.

What follows are a few of the developments from the conference.

The View From NIAID

On the first day of the conference, Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases (NIAID), addressed the crowd and outlined the progress and planned future approach of NIAID to control and end the HIV/AIDS pandemic at the national level.

To begin, Dr. Fauci noted how far researchers and physicians have come in treating the disease with a quick survey of some revealing numbers. Dr. Fauci, who began seeing AIDS patients in 1981, said that a patient who walked through the door at the NIH center in Bethesda, Maryland at that time had a mean survival time of 26 weeks.

“Today we’ve made extraordinary advances with the 30-plus drugs that we now have. We had nothing then,” Dr. Fauci said to the crowd of physicians and researchers. “Now,” he said, “if someone walks into our respective clinics today and is a 20-year old person, with mathematical modeling, you could project that that person would live to be at least 69 or 70 years old.”

That, Fauci stressed, is the good news. Still, there are sobering numbers on the other side. For every person receiving treatment, between two and three do not, and the numbers continue to swell globally, with 2.7 million new cases emerging every year.

Going forward, Fauci said that NIAID plans a three-pronged strategy: an aggressive “seek, test, and treat” approach; “cure” existing infections; and, most importantly in his opinion, the prevention of new infections (view the related webcast).

Emerging Therapies

Pharmaceutical companies in the past have looked forward to CROI to showcase the latest promising therapies being developed.

This year’s conference was no different, though the actual number of emerging drugs was less than in previous years, possibly due to the high standards that the current HIV/AIDS drugs demonstrate.

Introduced in 1996, treatments with combinations of at least three antiretroviral drugs, known as antiretroviral therapies (ART), continue to be the gold standard of care to reduce traces of the disease. Drugs discussed at the conference could potentially be added to that mix of standard treatments.

One promising agent undergoing a Phase 2 trial that was discussed at the conference is Gilead Science’s “Quad” pill, which is made of four drugs: elvitegravir, cobicistat (GS 9350), and Truvada (a combination of the two drugs emtricitabine and tenofovir).

After 24 weeks of the study, the Quad therapy’s efficacy compares favorably with another combination drug commonly used in ART, Atripla (efavirenz/emtricitabine/tenofovir). (See related AIDS Beacon news and CROI abstract 58LB.)

Also showing promise after a Phase 1 trial is TBR-652, a drug that blocks the action of the CCR5 receptor.

HIV uses the CCR5 receptor, which is a protein, as a door to enter targeted cells. TBR-652 interferes with that process, reducing the amount of virus in the body.

In the trial, TBR-652, which is being developed by Tobira Therapeutics, also showed effectiveness against CCR2, a receptor associated with serious diseases linked to inflammation in HIV-infected individuals such as metabolic syndrome and atherosclerosis (thickening of the artery walls).

Investigators say participants in the trial tolerated the drug well and that TBR-652 should not interfere with the efficacy of other HIV medications. TBR-652 is currently undergoing a Phase 2 clinical trial (see abstracts 53 and 598).

Emerging data announced at the conference for another CCR5 antagonist, vicriviroc, was less encouraging. After two Phase 3 trials, Merck’s vicriviroc along with standard ART failed to prove superior to ART alone (see abstract 54LB).

Diminished HIV Transmission Rates

Partners with different HIV statuses, known as serodiscordant couples, are a topic of particular interest to researchers as they try to slow the spread of the disease.

Researchers already know that the introduction of ART reduces the risk of transmission from the infected partner, most likely because the traces of the disease are diminished significantly as a result of the therapy. Ongoing research continues to affirm the role of ART in this drop-off.

In one paper presented at the conference, researchers looked at the “Partners in Prevention HSV/HIV Transmission Study,” a trial measuring rates of HIV transmission in heterosexual couples in seven African nations.

In each couple, one partner was infected with both herpes simplex virus (HSV) and HIV. They received acyclovir (Zovirax)-based ART to prevent transmission of HIV to their uninfected partner.

After following the more than 3,400 couples enrolled in the trial for up to 24 months, researchers observed a substantially diminished risk of HIV transmission within couples where the infected partner began ART (less than 0.4 percent compared to 2 percent).

Such findings suggest ART and other AIDS drugs may one day be placed in the same prevention category as needle exchanges and abstinence (see abstract 136).

For more information, please see the abstracts, podcasts, and webcasts available on the CROI Web site.