Have You Heard? New Hepatitis C Treatment
Hepatitis C is a liver disease that affects an estimated 242,500 Canadians.1 It is a result of an infection with the hepatitis C virus (HCV) and, if left untreated, can progress to advanced scarring of the liver (cirrhosis), end-stage liver disease, liver cancer, and even death.
Interferon is a substance that enhances the immune system and acts as an anti-viral and anti-tumour agent. Adding polyethylene glycol to interferon, through a process called pegylation, enhances its effectiveness. For the past decade, physicians have treated Hepatitis C with the combination of pegylated interferon and ribavirin, an anti-viral drug. The cure rate (eradication of the virus) with this combination is anywhere between 30% and 90%, depending on several factors, such as:
- the specific strain of the virus (HCV genotype),
- duration of the HCV infection,
- the amount of virus in the blood (HCV viral load),
- race, and
- the amount of damage to the liver (grade of liver inflammation and stage of fibrosis).
For the past two to three months, our office has been inundated with phone calls from patients, and all of the conversations seem to start with, “Have you heard about that new cure for HCV?” The short answer is “yes”, but there needs to be some clarification before anyone rushes into treatment.
There are actually two new medications, termed protease inhibitors (PIs), recently made available in Canada that will very likely increase the cure rates of HCV: Merck’s first-in-class, oral HCV PI, Victrelis™ (boceprevir), which was soon followed by Vertex’s Incivek™ (telaprevir).
It is important to know that neither of these medications are treatments for HCV on their own (monotherapy); they must be given in combination with pegylated interferon (peginterferon) and ribavirin. The current indication for these PIs is for the treatment of those who have a HCV genotype 1 infection. The cure rate in the clinical trials for this sub-group of HCV patients was between 63% and 79%.2,3 Both medications increase response rates in those who are naïve to treatment as well as in those who have been treated previously.4,5
Another important use for these medications is in individuals who did not respond to initial treatment with just peginterferon and ribavirin. One study showed that 38% of participants treated with boceprevir, along with the other medications, were able to eradicate the virus. One of the advantages of the addition of a PI to current therapy is that it could decrease the duration of treatment for those who respond quickly and who do not have cirrhosis. This lessens the duration of side effects that patients have to endure as well as saves costs.
Vigilant monitoring of the patient is required when on these new triple therapies. Particularly during the first 12 weeks, patients need more frequent blood testing, as mutations to the virus can occur if suppression does not occur quickly. A greater decline in hemoglobin levels (anemia) might occur with both medications, which may lead to increased levels of fatigue. With Incivek™, there is a reported increase in the incidence of rash, but it is manageable if dealt with swiftly. There is also the potential for drug-to-drug interactions, which physicians must supervise carefully.
Funding for these new therapies may be an issue on public and private drug plans. The cost of PI therapy ranges from $25,000 to $48,000 per treatment, and that does not include the additional cost of the peginterferon and ribavirin. These drugs are not currently covered under most public drug plans in Canada. This might change once these medications have gone through the Common Drug Review (a Canadian process for conducting objective, rigorous reviews of the clinical, cost-effectiveness, and patient evidence for drugs, that also provides recommendations to the publicly-funded drug plans in Canada).6 Currently there is public drug plan coverage for the cost of peginterferon and ribavirin for the treatment of naïve patients but not for those who have already been through a prior treatment.
An exciting time is before us, as we head into a new era of better treatments and higher cure rates for Hep C. Although there will be struggles with funding and accessibility, a greater number of HCV infected individuals can look forward to a life free of the virus and its potential complications.
Note: Incivek™ (telaprevir) was withdrawn from the Canadian market on March 31, 2015.