As we discover a sense of renewal with the beginning of 2012, I find myself more hopeful than I have ever been regarding the outlook for patients with hepatitis C virus (HCV) infection, including patients coinfected with HIV.
Over the years, we have been aware that treatment responses have been lower in HIV/HCV coinfected patients compared to those with HCV alone. This has been particularly true of those who had an HCV genotype 1 infection, where response rates have ranged from 25 to 35 percent with pegylated interferon and ribavirin. It has also been discouraging to see patients experience significant side effects with these two medications over months of treatment, only to see their virus rebound after treatment is stopped. I have seen many brave patients continue on despite severe fatigue, nausea, loss of appetite, weight loss and other side effects because they so desperately wanted to be cured of their HCV infection.
Well, I believe it is time to ring a bell of joy because so much progress is being made in the field of HCV therapy. The results of two major trials in HCV-infected patients have led to the approval of two new drugs, telaprevir and boceprevir, in the U.S. and Europe. Both of these drugs are HCV "protease inhibitors." These trials demonstrated that "triple therapy" including pegylated interferon and ribavirin plus a HCV protease inhibitor were much more effective than dual therapy.
This will also be a landmark year because we will see the final results of two trials of triple therapy in HIV/HCV coinfected patients. Both trials are using pegylated interferon plus ribavirin plus a specific HCV protease inhibitor. In one trial the protease inhibitor is telaprevir and in the other it is boceprevir. Drug interactions are being studied carefully as well, because of concerns about interactions with HIV medications. So far, the results are looking good with the specific HIV medications that have been chosen for use in the trial.
And triple therapy is just the beginning. Multiple other drug classes for HCV are being developed including HCV polymerase inhibitors, NS5A inhibitors and other drug classes as well. There are even trials of combination therapy without pegylated interferon. Cure rates without interferon are very encouraging, although we must keep in mind that we are still a few years away from getting any of these drugs in the clinic. Larger trials will also need to demonstrate ongoing safety and efficacy in greater numbers of patients.
Most of these new drugs target different parts of the life cycle of the virus so they are specific for HCV. This is just like all the drug classes for HIV: We have nucleoside analog reverse transcriptase inhibitors, protease inhibitors and many other classes of drugs. When you combine them and target the virus in various stages of growth, you can stop the virus right in its tracks. This approach has led to high rates of viral suppression of HIV. A similar approach with HCV promises not only to suppress the virus, but to eradicate it completely.
So let's go for the cure in 2012. I will be discussing the 24-week results of each trial in future blogs. The preliminary results look very encouraging! Stay tuned!!
With best wishes for a happy new year and a healthy liver!