December 20, 2005

HIV Snapshots From The ICAAC Conference

There were no HIV treatment headlines out of this week's Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC) in Washington, DC, but reports of some new drugs in development were enough to create a small buzz. “Pre-integration drugs might even rekindle the discussion of HIV eradication," HIV doc Ben Young, MD, PhD, told POZ at the meeting, referring to entry inhibitors and two other new classes of meds that prevent HIV from reproducing in your immune cells. However, Young added, “Remember the recent disappointment when [GlaxoSmithKline's] entry inhibitor turned out to be toxic after achieving great viral load drops? New drugs are just that—new. They can show early promise and then run into insurmountable problems in development.”

The promise was early but encouraging from a small, short trial of Panacos Pharmaceuticals’ PA-457, a new drug in the up-and-coming maturation inhibitor class. By itself (in monotherapy), PA-457 toppled HIV viral loads without major side effects. Also, GSK's new protease inhibitor (PI), brecanavir, did well in subjects who had developed resistance to other PIs.

One study presented at ICAAC raised serious questions about the extra challenges faces by some people with HIV. In ongoing research on two PI-sparing regimens (Combivir plus Sustiva and Trizivir plus Sustiva), Roy Gulick, MD, reported that treatment failed fastest in study participants who were African American, as well as in those coinfected with hepatitis C. Kimberly Smith, MD, of Rush Memorial hospital in Chicago, offered some possible explanations—Sustiva’s higher drug levels in African Americans, for instance, or the fact that the African Americans in the study were more likely to have hepatitis C and lower T-cell counts.

Later, chatting with pharmaceutical company reps about research in the works, POZ learned that Gilead folks are optimistic about the company’s third attempt to formulate Truvada with Sustiva in a single-pill HIV combo ("the triple"). Abbott still can’t provide a timeline on reformulating Norvir to make it more GI-friendly, as they’ve done with Kaletra (which contains the Norvir boost). And results are expected soon from an ongoing Bristol-Myers Squibb study of Reyataz taken by people on their first HIV combo. At issue: Does Reyataz still avoid the PI problem of raising blood fats if it’s boosted with Norvir (as opposed to being swallowed solo)?

Outside pharma circles, though, there were questions about the usefulness of such research. Treatment advocate David Scondras of Boston’s Search for a Cure sees a lack of experimentation in favor of wasteful and unnecessary retesting of old combos to prove one slightly better than another—a sentiment echoed by New York City HIV doctor Paul Bellman, MD. He characterized a two-year GSK trial of Epzicom/Kaletra versus Truvada/Kaletra, now enrolling, as grappling with questions that don't need to be answered. "The doctors and researchers need to stand up and stop this kind of waste," Bellman said.

GSK’s Mark S. Shaefer argued, on the other hand, that “Part of our job is to establish the comparative safety and efficacy of our compounds.” He said that, “If you took this [argument] to the extreme, people would have said that Epzicom and [Viread] were both potent and could be used together. However, we now know that this combination should never be used together because it was part of a well designed clinical trial.”
 
Hungry for more details on these and other studies mentioned at ICAAC? Check out NATAP's reports.