“This marks a turning point in the treatment of hep C,” says Natalie Bzowej, MD, a liver disease specialist at California Pacific Medical Center in San Francisco – part of the Sutter Health network – and one of the investigators on the trial. “Right now we can cure less than half the people in the US with hep C, but this new medication – and the recent FDA approval of it – means we can hopefully increase that number to closer to 80 percent.”
The results stem from a Phase 3, randomized, double-blind, placebo-controlled study, considered the gold standard for clinical research. The team followed 1,095 people infected with genotype 1 chronic hepatitis C virus (HCV) – the most common form of the virus in the US and Europe – who had not previously been treated for the disease.
Patients were assigned to different treatment groups. One group was given pegylated-interferon and ribavirin alone for 48 weeks; the other group was given a course of Incivek for 8 or 12 weeks, in combination with the other two medications, followed by a course of pegylated-interferon and ribavirin alone for 12 or 24 weeks. The treatment period for Incivek was no more than 12 weeks and the total time for patients on the combination therapy was either 24 or 48 weeks.
In the group treated with pegylated-interferon and ribavirin alone, 44 percent of patients achieved what is called a sustained viral response (SVR) – defined as having undetectable levels of HCV 24 weeks after the last treatment – effectively a viral cure. However, in the group treated with pegylated-interferon, ribavirin and Incivek, 79 percent of patients achieved SVR.
“Hepatitis C can lead to liver failure, cancer, even death,” says Bzowej. “In the past the best we could offer patients was a year of treatment that resulted in a cure for fewer than half of them. Many patients had to drop out of treatment because the side-effects of the drugs are so toxic. For many of those who failed treatment their only real option was to get a liver transplant. This new drug means we can significantly increase the number of patients who are cured, and reduce the number who need to go on the transplant waiting list.”
Another advantage to the Incivek-combination thereapy was that more than 60 percent of those treated for the first time were able to complete the treatment within 24 weeks. That is less than half the time of the current treatment regimen.
Incivek is a pill that is taken three times daily. It is a protease inhibitor and works by blocking an enzyme that the hep C virus needs to make copies of itself inside the body. Incivek is made by Vertex Pharmaceuticals Inc. and was recently approved by the FDA. Side effects of the medications include skin rashes, anemia, fatigue, itching, nausea, diarrhea, vomiting, and taste changes.
Hepatitis C is a liver disease that affects almost four million Americans, 75 percent of whom do not know they are infected. In its early stages it displays no symptoms and often by the time it is detected it has caused liver damage. Hep C, which is four times more common in the US than HIV, is the leading cause of liver transplantation in the US and is estimated to play a role in 4,600 to 12,000 deaths every year.
Dr. Bzowej and several of the other researchers involved in this study received consulting fees and grants from Vertex and other pharmaceutical companies.
Material adapted from California Pacific Medical Center.