HIV and ID Observations

Both ICAAC and IDWeek (formerly IDSA) are now over, IDWeek ending this past Sunday.

These are the two large Infectious Diseases scientific meetings that take place each year in the Fall. They’ve been battling it out for years for attendance, but it looks like finally IDWeek (formerly IDSA) has won the Fall slot — ICAAC is moving next year to the Spring, where I assume it will stay.

Regardless of which meeting one attends, or when they happen, a common complaint heard from HIV-specialist types goes like this:

Well, it’s not like CROI — hardly anything here new and important.

Well, of course it’s not like CROI — that’s a whole meeting devoted to HIV research, both clinical and basic. It’s unreasonable to expect there will be anywhere near the number of oral sessions, posters, and plenaries on HIV at non-CROI meetings because, obviously, ICAAC and IDWeek have to represent the full breadth of material in the field.

But there usually is some good stuff, studies that could significantly impact clinical practice. Here’s the most important HIV study from ICAAC, and soon the notable ones from IDWeek.

In the STRIIVING study, 551 virologically suppressed patients were randomized to stay on their regimen or to switch to ABC/3TC/DTG; it was open label (images thanks to the essential natap.org):

Eligibility criteria included being on first or second regimens with no history of treatment failure, and HLA-B*5701 negative.

At the end of 24 weeks, treatment success (HIV RNA < 50 copies by “snapshot”, meaning also still in study) was observed in 85% and 88% of subjects in the switch vs continue current ART arms respectively:

There were no virologic failures or emergent resistance in either arm. 4% (10 total — not 10% as I erroneously wrote) of the ABC/3TC/DTG group stopped the study due to adverse events (none considered serious) vs. zero in the continued ART arm. Treatment satisfaction at week 24 was significantly higher for those on ABC/3TC/DTG.

A few comments on these results, which were both reassuring and disappointing at the same time:

• There are now four available single-tablet treatments for HIV, and all have had prospective, randomized switch studies similar in many ways to this one — previously TDF/FTC/EFV, TDF/FTC/RPV, TDF/FTC/EVG/COBI for PI and NNRTI switches.
• Up until now, all of these studies numerically (if not significantly) favored the switch to the single tablet — not really surprising, as patients entering these studies typically want to simplify their regimens.
• Why didn’t this happen in STRIIVING? I can think of three kind of overlapping reasons:  1) A high proportion of subjects were already receiving integrase-based (and hence well-tolerated) treatments; 2) Also a high proportion were already on single-tablets; 3) All of these single-tablet treatments (before this one) would necessarily include TDF/FTC, and many of the multi-tablet regimens would as well. There’s probably a somewhat less-favorable tolerability profile of ABC compared with TDF, independent of hypersensitivity reactions (which didn’t happen in this study, obviously, since all were HLA-B*5701 negative).

An interesting irony is that the SINGLE study — which emphatically put DTG on the map — demonstrated superiority of ABC/3TC + DTG over TDF/FTC/EFV, results driven by better tolerability. Think about that one, and what it says about efavirenz.

Take-home message? Switching to ABC/3TC/DTG will mostly be successful (especially virologically), but a small fraction might have side effects that makes them prefer what they’ve already been on.

Anyway, that’s the most important HIV study at ICAAC. Coming soon, the most important one (or two or three, haven’t decided yet) at IDWeek.

Good time for a baseball moment. Congrats, Cub fans! (So far.)

[youtube http://www.youtube.com/watch?v=WOYME2Q4nAg&w=560&h=315]