Annette M. Boyle
LOS ANGELES — The approval last year of the first new drugs for treatment of hepatitis C (HCV) in 20 years substantially increased the rate of virologic cure for patients with the most common form of the disease. At the same time, the complex regime of medications has made adherence more difficult, increased the likelihood of development of treatment-resistant strains of HCV and made the role of the pharmacist in HCV management more important than ever.
Pamela S. Belperio, PharmD, BCPS, AAHIVE, National Public Health Clinical Pharmacist, VA Greater Los Angeles Healthcare System
The new drugs, boceprevir and telaprevir, are the first commercially available HCV direct-acting antiviral agents. Both drugs are HCV NS3/4A protease inhibitors (PIs) that target viral replication and are Food and Drug Administration (FDA) approved for the treatment of adults with chronic HCV infection caused by genotype 1 viruses. Genotype 1 accounts for 70% to 90% of the cases of HCV in the United States.
Genotype 1 HCV has been the least responsive to the traditional dual therapy of weekly injections of pegylated interferon and daily oral ribavinin. According to the FDA, less than 45% of HCV patients with genotype 1 achieve sustained virologic response (SVR) or cure as indicated by undetectable plasma HCV levels six months after cessation of dual therapy. More than 70% of genotypes 2 and 3 achieve SVR with the pegylated interferon/ribavinin combination.
The new three-drug regimen adds either boceprevir or telaprevir to pegylated interferon and ribavinin. Neither of the new drugs can be used on its own to treat HCV.
“New hopes for a cure have been made possible with the addition of these new treatments. Patients who have never received HCV treatment may have up to a 25 to 30% better chance of achieving a SVR with the new triple therapy compared to traditional treatment with pegylated interferon and ribavirin alone,” said Pamela S. Belperio PharmD, BCPS, AAHIVE, National Public Health Clinical Pharmacist, VA Greater Los Angeles Healthcare System.
Patients who had been treated in the past but relapsed or had insufficient response may have up to a 60% chance of responding to the new treatment combination, Belperio told U.S. Medicine.
The complex triple therapy regimen requires patients to take 12 to 18 pills a day in three doses at seven- to nine-hour intervals. In addition, the pills must be taken with specific foods and often produce troublesome adverse effects such as taste changes, tiredness, rash, anemia and low energy — all factors that Belperio notes are associated with high rates of non-adherence. Patients who do not strictly follow the treatment protocol are unlikely to achieve SVR in the current course and may also limit future treatment options.
“BOC and TVR carry the risk of inducing HCV resistant mutations, and it is likely that cross-resistance to future generations of PIs will develop in some patients who do not achieve SVR,” noted the authors of the new VA guidelines for management and treatment of HCV, published in the American Journal of Gastroenterology this spring. “Extensive patient monitoring for virologic response and counseling on adherence will be necessary to minimize the development of resistant variants.”
This need for close monitoring makes the role of pharmacists critical to HCV management in the VA.