Cost-Effectiveness of Treatment for Hepatitis C
JOHN B. WONG, MD: I’d like to thank Dr. Schiff and Dr. Maddrey for inviting me to share with you some of my work on the cost effectiveness of hepatitis C treatments, in particular combination therapy. As a physician, I care more about effectiveness than cost, so let me turn to that first.
Well, what’s known about the effectiveness of treatment? This slide extends some of the results from the US and international trials that John presented earlier. It presents the probability of sustained virologic response for some of the clinically relevant subgroups, and I’ll walk you through the slide. Histologically, patients may have mild, moderate hepatitis or cirrhosis, or they may have viral loads less than or greater than 2 million, or they may be genotype 1 or other than 1. The y-axis presents the sustained virologic response. The bars on the left represent 48-week interferon therapy alone. The two bars to the right in darker green and a red present the likelihood of sustained virologic response with either 24-week or 48-week combination therapy.
Notice the trend. Basically, either 24- or 48-week combination therapy results in a much higher sustained response rate across all of these clinically relevant subgroups. I’d like to in particular focus your attention on three groups that have been traditionally very hard to treat with interferon monotherapy: those with cirrhosis, those with high viral loads, and those with genotype 1. As you can see, there’s a substantial improvement so that the sustained response rate exceeds 20 percent in these traditionally clinically difficult to treat patients.
Now, when you talk about cost effectiveness, policy makers, HMO directors, people who are interested in money want to have an effectiveness measure that they can compare. And it’s very difficult to compare a sustained response rate to whether or not they should fund bypass surgery or any of the other new interventions, such as remicade for Crohn’s disease. How does that compare? Well, to be able to translate or to be able to do that comparison, these clinical trial results must be translated into a uniform effectiveness measure that these individuals are interested in knowing. And the standardly recommended unit is life expectancy benefit.
In the interests of time, I won’t belabor it, but we constructed a computer simulation model that took these 1,744 patients and projected out the results from the clinical trial over the lifetime of the patients in the trial. This slide presents the results in terms of the life expectancy benefits of medical interventions. Focus for a second on the second bar. Forty-eight weeks of interferon and ribavirin therapy should, in our analysis, extend the life expectancy of this group on average by about three years.
How does that compare to some of the other things that we do in medicine in terms of life expectancy benefit? Well, bypass surgery buys you about a year. Pap smear or stool guaiac screening buys you a few months.
Focus your attention lastly on this bar on the left. In a hypothetical study in circulation, Dr. Savatt at the Beth Israel Hospital found that if you could eliminate coronary artery disease in 35-year-olds, on average the US population would increase their life expectancy by about 3 years. So in the spectrum of medical effectiveness, this 3-year gain is a big win.
Turning now from effectiveness to cost, which is on everybody’s mind, in addition to the life expectancy benefits, we also extrapolated, based on the 1,744 patients in the clinical trial, both the US and international, what the cost of therapy should be. And we estimated that cost to be $10,000 roughly. Now, that’s probably lower than you’re thinking about or that you’ve heard or that your HMO provider or whoever is regulating your pharmacy is telling you. As is part of standard economic practice, we used average wholesale prices for the drugs. In addition, this figure incorporates the 24-week stopping criteria that John mentioned earlier today. That saves you a few thousand dollars. Thirdly, just so that you know the components of this cost, it includes not only drug costs, but office visits, additional office visits for side effects as occurred within the clinical trial, laboratory testing, and lastly, because ribavirin has been shown to be teratogenic in animal studies, it includes some contraception costs.
Now, to put that $10,000, roughly, in perspective, let’s look at the cost for treating somebody with cirrhosis. A 40-year-old, a 50-year-old, or a 60-year-old costs over the remainder of their life in terms of estimated hospitalizations, medications, outpatient visits, anywhere from $30 to $50,000.
Let’s compare combination therapy to something that’s well-accepted: coronary artery bypass surgery. Combination therapy costs about $10,000. When you spend that $10,000 you buy about 3 years of life. In contrast, bypass surgery costs around $27,000 and you only buy about 1.1 years. I won’t get into the relative value of the heart versus the liver in this audience, but I’ll let you make your own judgments.
In conclusion, left untreated, hepatitis C is likely to result in cirrhosis in about somewhere between 15 and 45 percent of patients, if you extend the natural history studies of cirrhosis to 20 years. On average, about 28 percent of patients after 20 years. The cost of interferon and ribavirin combination therapy should be offset by future savings through the prevention of liver-related complications. Thank you for you attention.