July 25th, 2008

Word salad: Jalapenos, abacavir, doripenem, and PAVE

Some miscellaneous recent items from the ID/HIV world jumbling around this Friday:

  • Tomatoes are off the hook — it’s the jalapenos that likely caused the recent salmonella outbreak.  Since this is the only time of year that tomatoes are even edible in this part of the world, I for one am quite relieved.  I am sure many are wondering how bacteria could survive on those very hot peppers.
  • HLA-B*5701 testing is now “officially” recommended before abacavir use to reduce the risk of hypersensitivity — it’s now in the package insert.  We started doing this test two years ago (at the strong encouragement of some British and Australian colleagues), and it makes all the difference in the world when prescribing this drug — the counseling to patients about the safety of abacavir drops from a 30-minute terrifying review of possible death to a 5-minute, “this could happen, but it won’t.”  Two further thoughts:  1) It’s too bad we didn’t have this tool available sooner (likely lots of debate within the boardrooms of the manufacturer on the pros and cons from a sales perspective); and, 2) Let’s hope that other companies can learn from this lesson and, if such tests are potentially available to improve patient safety, they move ahead quickly to validate them.
  • Oh, and the other abacavir label change is related to the DAD data and the possible association between abacavir use and cardiac disease.  Not much has changed since I last covered this issue, but one wonders what we’ll hear soon, either confirming or refuting this association.  (Or likely, both confirming and refuting it.) 
  • In other FDA news, an advisory panel was split on whether to recommend approval of doripenem for treatment of nosocomial and ventilator-associated pneumonia — but overall narrowly favored approval.  (No action by the FDA yet.)  Not going to get into details of this particular drug or indication — the FDA’s decision is unlikely to change clinical practice in the short run — but isn’t it peculiar that we have a gazillion (stealing a word from one of our ID Fellows who speaks California-ese) cephalosporins, but only 4 carbapenems?  And no oral option?  Hey, imipenem was approved by the FDA in the mid 1980s!  I asked a medicinal chemist about this a few years ago, and apparently it’s not so easy to synthesize these drugs — but the rise in ESBL-producing gram negatives certainly could (and should) spur further drug development.
  • Last, the NIH halted plans to conduct the PAVE 100 HIV vaccine trial.  The reason, obviously, is that this adenovirus-based vaccine strategy is similar in many ways to the one tested in the STEP trial — which showed that the vaccine not only didn’t work in protecting from HIV infection or lowering HIV RNA levels, but led to an increase in the risk of HIV acquisition for those persons vaccinated who had pre-existing adenovirus immunity.  The challenges of developing an effective AIDS vaccine are legion, but here’s a particular tough one:  can you imagine trying to write the informed consent for the next major efficacy trial?  Yikes.

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HIV Information: Author Paul Sax, M.D.

Paul E. Sax, MD

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Infectious Diseases

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