Pharmacy News
HCV Protease Inhibitors Bring New Options for Patients
[August 1, 2011, AJHP News]
Kate Traynor
BETHESDA, MD 15 July 2011—The care of patients with hepatitis C virus (HCV) infection is poised to change dramatically with the recent approval of two drugs that directly target viral replication and may help to eliminate the infection.
The newly approved drugs are boceprevir, which is marketed as Victrelis by Merck, and telaprevir, which Vertex Pharmaceuticals sells as Incivek. Both drugs are HCV NS3/4A protease inhibitors indicated for the treatment of adults with chronic HCV infection caused by genotype 1 viruses, the most common type affecting patients in the United States.
Current standard drug therapy for chronic HCV consists of weekly injections of a pegylated interferon alfa product in combination with daily oral ribavirin. According to FDA, less than half of patients with chronic HCV infection have undetectable blood levels of the virus, known as a sustained virologic response (SVR), after completing standard therapy.
In clinical trials, the addition of boceprevir or telaprevir to the standard regimen increased the likelihood of an SVR. About two thirds of clinical trial participants in Phase III trials whose regimen included boceprevir or telaprevir achieved an SVR, according to results described in the drugs' labeling.
According to FDA, an SVR after the completion of treatment "suggests that HCV infection has been cured."
"This is a very exciting time," said Helen Yee, hepatitis C clinical pharmacy specialist and associate director of the Veterans Affairs Medical Center San Francisco Hepatitis C Resource Center. Yee manages an HCV clinic and is updating clinical guidelines used by the Department of Veterans Affairs (VA) for the treatment of veterans with chronic HCV infection.
"Overall, this really represents a significant advance in improvement in the outcomes of patients who undergo antiviral treatments for HCV genotype 1," Yee said. "The goal of these new treatments in genotype 1 is to achieve an SVR and ultimately prevent the complications associated with hepatitis C, such as liver cancer, liver failure, and transplantation."
According to a November report from VA, the Veterans Health Administration (VHA) is the largest provider of HCV care in the United States.
The report states that 2.6% of the 5.6 million veterans treated in VHA facilities in 2008 had a diagnosis of chronic HCV infection. During that year, each health care system within VHA cared for chronically HCV-infected veterans, with caseloads ranging from 26 to 4476 patients per facility.
"We have a huge population of hepatitis-C-infected patients who are in care," Yee said.
She said the "pill burden" for the new drugs is high—12 boceprevir capsules or 6 telaprevir tablets per day, plus up to 6 ribavirin capsules per day.
And the recommended treatment regimens for the anti-HCV drugs are complex. Patients must complete 4 weeks of treatment with peginterferon alfa and ribavirin before adding boceprevir to the care plan. The three-drug regimen is then continued for up to 32 additional weeks, depending on the patient's previous treatment history and the virologic response to the regimen. Some patients continue taking peginterferon alfa and ribavirin for 12 more weeks.
Patients taking telaprevir should receive triple-drug therapy for 12 weeks then stop taking the telaprevir but continue treatment with peginterferon alfa and ribavirin for up to 36 additional weeks.
The duration of treatment is determined by periodic laboratory monitoring of patients' HCV RNA levels. Patients must also be evaluated for drug-related adverse events, such as neutropenia, which was reported in clinical studies of boceprevir, and rashes, which were reported during studies of telaprevir.
Yee said the complexity of these regimens and the fact that many medications interact adversely with the new HCV drugs offers pharmacists opportunities to become involved in the care of patients with HCV infection.
She also said pharmacists can encourage hepatitis A and B vaccination for HCV-infected patients and suggest strategies to maintain their liver health. These include counseling patients to avoid alcohol use and to always consult with a health care provider before taking any new medication to evaluate whether it can adversely affect the liver.
At Fairview Specialty Pharmacy in Minneapolis, pharmacists are deployed at University of Minnesota Medical Center, Fairview, as part of the care program for patients with chronic HCV infection. Patients with the infection are also served through the specialty pharmacy's regional network.
Ann McNamara, clinical development manager for the specialty pharmacy, said discussions are underway with the university hospital staff about the use of the new protease inhibitors.
She said a university nurse practitioner who manages the HCV care program will work with patients and review their medications before starting them on the new regimens. The review could reveal that a patient needs to change or discontinue certain medications, such as statins, during HCV therapy.
"For more complicated patients, [the nurse] will refer to one of our pharmacists that is located in the clinics at the University of Minnesota for a medication review," McNamara said. She said many of the university's patients have complex conditions, such as cirrhosis, or have previously failed to achieve an SVR on standard combination therapy.
Both Yee and McNamara said patients are aware of the new therapies, and many with HCV genotype 1 infection have been waiting for the drugs to become available so they could begin treatment.
Yee said in early June that requests to add both drugs to VHA's national formulary were under review.
"We're preparing our system for these agents," Yee said.
Ribavirin and all FDA-approved interferon alfa products, including pegylated interferons, are already on the VHA formulary for the treatment of veterans with chronic HCV, according to VA's November report.
McNamara said her staff is speaking with insurance payers about the formulary status of the new drugs and working with patient-assistance programs to help patients afford the therapy.
She said the pharmacy is also asking payers whether the drugs, which are packaged in a 28-day-supply, can be dispensed in smaller increments.
When laboratory values indicate that the patient is not responding to therapy, treatment should stop, according to the drugs' labeling.
"Unfortunately before those labs come back, we have to dispense the next refill," McNamara said. "[Patients] may only use a few days out of the 28-day supply of three prescriptions," which she called "a very expensive waste."
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