Why Incivek and Victrelis Herald a New Era in Hepatitis C Treatment
An Interview With Barbara McGovern, M.D.
June 2, 2011
Myles Helfand: Let's talk a little about those people for whom hep C treatment hasn't worked in the past. The indication for boceprevir notes that it's not for use by some of these people. Why is that?
Barbara McGovern: I think what you might be referring to is the "null responder." Boceprevir is a very good drug, and in people who relapsed in the past with peg and ribavirin, it has excellent response rates in those patients. It also has excellent response rates in patients who have had a partial response, which basically means that by 12 weeks they had viral load declines of more than 2 logs [99 percent], but did not reach an SVR.
I think you're referring to the "null responders," which means the people who took peg and ribavirin and basically had minimal changes in their viral load responses. They did not study the drug in that population. However, telaprevir was studied in null responders. About a third of those patients do respond when you give them triple therapy -- which is, you know, not as good as the other response categories. But knowing that we're layering a potent agent onto two other agents that the patient barely responded to, it stands to reason that you certainly wouldn't expect as good a response. It's still better than no response.
Myles Helfand: Is there cross-resistance between boceprevir and telaprevir? If a person fails one, could they try another?
Barbara McGovern: Boceprevir and telaprevir have very extensive cross-resistance. That's really important for clinicians to know, and for patients to know.
You yourself referred to HIV a couple of times in this interview, and it keeps harkening back to that. When we first started with HIV medicines, we were so careful to discuss adherence with our patients, and this was such a big part of counseling of patients.
This will have to be a very big part of counseling hep C patients. The good part about this is that it's not for the lifetime of the patient. So the hep C patients have it relatively easy, compared to our HIV patients.
Myles Helfand: Well, except that the side effects are awful.
Barbara McGovern: Yeah. I mean, all these meds -- having a rash and pruritis [itchiness] and all that stuff. I mean, it's going to be tough. But when you think about HIV, taking these meds forever, and having to remember to take pills every single day. However, for the hep C patient, if they are really adherent to these regimens, which is going to be difficult because it's three times a day -- I think taking that midday dose is always going to be hard, especially for people who are working and busy; it's so difficult to remember that midday dose -- I think that's going to be a barrier to adherence. But it's going to be something we have to really emphasize to patients.
If they take it as prescribed, then hopefully they'll get to virologic suppression. And we know that once you get to virologic suppression, then the risk of resistance is very, very low.
If you're taking your medicines in a hit-and-miss fashion, the risk of resistance is extremely high. And then we don't have that second drug to fall back on, in terms of sequencing of therapy. We're not there yet. In fact, it's going to be a while before we get another protease inhibitor that doesn't have this extensive cross-resistance.
Myles Helfand: Why has it been almost a decade since the last hep C drug was approved? And where do we go from here?
Barbara McGovern: Well, now we're just on this incredible pipeline of drugs. It's incredibly exciting, what's coming down the pike.
The discovery of the virus occurred only in 1989. Then you have to start screening compounds [to treat it], trying to find a compound in vitro; the in vitro models were difficult because it took a long time to find a model that actually was something you could work with. So that was a big, big stumbling block. But once that model was found, then that quickened the development of all these different drugs, working at different parts of the lifecycle.
And now, the fruit! All these companies are working simultaneously on it. Now we're seeing the fruition of that. Everyone, kind of in concert, is coming up with all these wonderful drugs. It's just going to be a matter of time, where we're going to have polymerase inhibitors, and more protease inhibitors, and less cross-resistance. We'll have sequencing of therapy, and genotyping and phenotyping [types of resistance tests] will eventually become important in clinical practice. Not now, because we have hardly any drugs. But we're just getting going out of the gate right now. And down the road is just going to be better and better and better, and hopefully, eventually we'll get rid of peg and ribavirin.
But it's just incredibly exciting to look forward. I just can't wait to see, even in just five years, how different things are going to be. The paradigm for treatment is going to be drastically different.
Myles Helfand: It sounds almost like you're painting a picture where, in 5 or 10 years, hep C treatment will be similar to what happened to HIV treatment from 1996 to 2006.
Barbara McGovern: Exactly. That's the exact parallel.
[This transcript has been edited for clarity.]
To learn more about these new additions to the hepatitis C treatment family, read AIDS InfoNet's fact sheets on Incivek and Victrelis. If you have specific questions about these new drugs, or about treatment of HIV/hepatitis C coinfection in general, you can ask Dr. McGovern directly in our "Ask the Experts" forum on coinfection.
Copyright © 2011 The HealthCentral Network, Inc. All rights reserved.
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