On HCV, These Questions Three

Paul Sax • August 25th, 2012

Categories: Infectious Diseases, Patient Care, Research

In the fastest-moving area of ID drug development, answers are eagerly sought to the following questions three:

1. What does the bad news on BMS-986094 — formerly INX-189 — mean for other investigational HCV nucleotides? Severe cardiotoxicity, fatal in one case, has ended the drug’s development. Importantly, nothing similar has thus far been observed with the structurally-similar IDX184, but that drug has been placed on “clinical hold” by the FDA. By contrast, the nucleotide GS-7977 is apparently different enough chemically that studies are for now continuing. One take-home message: drug development is risky business.
2. When will the alphabet soup of terms used to describe HCV treatment response be abandoned? HCV treatment either works, and you’re cured, or it doesn’t. But because the treatment is so cumbersome and so long, there’s a whole slew of ways to describe how things are going before you get to that point. Let’s see, there’s RVR (rapid virologic response, or no virus detected at 4 weeks); eRVR (extended rapid virologic response, or no virus detected at weeks 4 and 12 — used in this study of daclatasvir); EVR (early virologic response, which really isn’t that early, because it’s week 12, and it can be either pEVR — for “partial” — which means HCV RNA drops by more than 2 log but is still detected, or cEVR — for “complete”, which means it’s undetectable); ETR (end of treatment response, or no virus detectable at end of treatment); and of course SVR (sustained virologic response, now available in many flavors, depending on the week after stopping treatment you want to measure it — 2, 4, 8, 12, 16, 24,etc). For now, with IF/RBV +/- telaprevir/boceprevir and “response-guided” therapy still ruling the day, we’re stuck with this mish-mosh of terms, but I suspect most of this stuff will be irrelevant pretty soon, except for the bottom line — how many are cured? Doesn’t that sound better than “How many are SVR-12′d?”
3. So when precisely will these new drugs become available? Seems pretty obvious right now that if you’ve got HCV and can wait for better treatments, you should. Treatment became more effective with telaprevir and boceprevir, but it also got more complicated, toxic, and expensive. Things have to get better, and they will — especially with interferon-free options. Regardless, no one knows exactly when these new drugs will be available for use outside of clinical trials — 2013-2014 a broad estimate — and all kinds of things could hold up their approval (see #1 above). Plus, some patients can’t and shouldn’t wait for better options because they have advanced liver disease. Just this last week, two such individuals came in for evaluation — both with HIV, both with prior treatment failure on IF/RBV, both with Stage 3/4 fibrosis on liver biopsy. Should they wait for daclatasvir, GS-7977, TMC-435, ABT-450/r + ABT-333, etc? Probably not.

For the record … what is the airspeed velocity of an unladen swallow?

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