U.S. Researchers Model Impact of Interventions to Shrink Hepatitis C Epidemic
Researchers at Yale University and the pharmaceutical company Merck have developed a sophisticated computer model of the hepatitis C virus (HCV) epidemic in the United States. The Yale team estimated that there are up to five million people living with HCV in the U.S. and about 100,000 are treated each year.
Using high-performance computers, the research team found that if the number of HCV-infected people in the U.S. who received treatment each year were to increase four-fold, major positive impacts on the epidemic would occur, including the following:
- more than half a million cases of cirrhosis could be prevented
- more than 250,000 deaths arising from HCV-related complications could be prevented
Furthermore, by increasing opportunities for the offer of HCV testing followed by swift linkage to care and treatment, the pool of infected people would significantly diminish over time. Additional projections from the Yale analysis as well as from teams at other universities are presented later in this CATIE News bulletin. All of these projections and analyses have underscored the issue of drug pricing as an important barrier to the timely eradication of the HCV epidemic.
Researchers put an enormous volume of information into their model, including data collected between 1992 to 2014 from many key studies about HCV testing and, when possible, treatment. An important aspect of the Yale model is that it assumed that future use of DAAs would result in cure rates of about 95%. For simplicity, we have rounded off figures in our report.
The Benefits of Increased Access to Treatment
Based on multiple scenarios and calculations, the Yale team detailed how many people would need to be treated each year so that the population of HCV-infected people could eventually decrease by 80%:
- Treating 100,000 people each year (the present situation) would lead to an 80% reduction in the number of HCV-infected people by 2040.
- Treating 200,000 people every year would lead to an 80% reduction in the number of HCV-infected people by 2031.
- Treating 300,000 people each year would lead to an 80% reduction in the number of HCV-infected people by 2028.
- Treating 400,000 people each year would lead to an 80% reduction in the number of HCV-infected people by 2025.
By intensifying opportunities for treatment, major reductions in cases of cirrhosis could occur under the following scenario:
- Treating 200,000 people each year would result in nearly 290,000 fewer cases of cirrhosis and 143,000 fewer deaths from HCV-related complications between now and 2040.
The Importance of Testing
Other research teams have found that many people who are infected with HCV do not know their infection status. Therefore, the Yale researchers underscore the importance of offering HCV testing to help uncover this infection and get people linked to care and treatment. The Yale team said that "without expansion of HCV screening at least 463,000 [undiagnosed cases of HCV] would remain untreated through [the year] 2040. ..." Specifically, the researchers stated that if rates of HCV testing remain where they are now, new cases of HCV infection will only "be reduced, at most, by 15%."
The researchers also suggest that HCV testing be offered in the emergency rooms of hospitals. Studies have found that this can be effective in helping to uncover HCV infection and linking people to care and treatment.
Focus on a Vulnerable Population
In the U.S. today, according to the Yale researchers, "new [HCV] infections occur principally among [people who inject street drugs] and therefore will not be appreciably reduced without increasing more [opportunities offering testing, care and treatment] for this vulnerable population."
The Yale team estimates that presently only about 4% of people who inject street drugs get tested for HCV. The team stated that if this rate of testing does not increase, large declines in the rate of new infections will not occur until 2040.
The researchers said that to eventually reduce cases of new HCV infections in this population by 90% would require "universal [HCV] screening and at least 20% [of new cases of HCV would require treatment each year]."
Alternatively, the team found that if 20% of people who inject street drugs are screened for HCV every year and 30% of newly diagnosed HCV cases are offered treatment each year, eventually "at least 90%" of people who inject street drugs would no longer have HCV.
The team underscores the importance of providing medical care "in a nonjudgmental setting" for people who inject street drugs.
The Possibility of Eliminating an Epidemic
To eliminate the HCV epidemic, the team stated that programs will need to "incorporate enhanced HCV [testing] and treatment with needle and syringe exchange programs," as these help to reduce the spread of HCV. Furthermore, the researchers said that "opiate substitution therapy" will need to accompany such programs in order to assist people who are trying to recover from addiction. All of these efforts focused on preventing HCV infection (and in some cases re-infection) are necessary because a highly effective vaccine to prevent HCV is unlikely to become available in the foreseeable future.
Researchers who construct models of the HCV epidemic need to bear in mind that, in addition to addiction, the psychosocial drivers that lead to HCV infection -- including anxiety, depression and other mental health issues -- need to be addressed. For some people with HCV, this infection is merely one on a list of issues with which they grapple. Therefore, psychosocial support is an important part of recovery from HCV and avoiding re-infection in the future.
The Yale researchers pointed to other challenges involved in tackling the HCV epidemic, such as the following:
- the "high costs of treatment" -- if treatment costs are not at a level that health systems can afford, an end to the HCV epidemic will not occur quickly and perhaps even not at all
- the "[un]willingness" of some practitioners to treat people with HCV who are also struggling with addiction
Focus on Drug Costs
The cost of DAAs for HCV is generally expensive, so teams of researchers are beginning to assess the impact of drug prices on budgets of health systems. (Costs and prices listed below are in $US.)
"The retail costs of the antivirals for a single course of the most common HCV treatment regimen approaches $100,000," said Hal Yee, MD, PhD, from the Los Angeles County Department of Health Services. Furthermore, he notes that in 2014 total spending on medications for the treatment of HCV exceeded $12 billion. He said that this amount "represented more than 3% of the nation's total prescription drug [spending]." Dr. Yee added that much of the increase in spending on new drugs occurred because of the costs of HCV therapy. Therefore, he concluded that "... funding to treat every [HCV] infected person immediately appears problematic."
A team of researchers at the University of California at San Francisco (UCSF) has been investigating the cost-effectiveness of HCV treatment for all patients in the U.S. The team focused on the strain of HCV most common in the U.S. -- genotype 1. The researchers found that providing treatment to patients when there was a relatively small degree of liver injury was cost effective. However, they also said that "if only 50% of eligible patients with HCV genotype 1 were to be treated with the combination of sofosbuvir + ledipasvir [sold as Harvoni] during the next five years, the cost of [this treatment] in the U.S. would be $53 billion."
Furthermore, the UCSF researchers acknowledged that some health plans and government agencies are able to negotiate a reduction in the cost of medicines with pharmaceutical companies, though the scope of discounts is not usually made public. The researchers added that if payers were able to negotiate a "46% reduction in the [average price of drugs], the cost of treating 50% of patients with HCV genotype 1 during the next five years could be as high as $29 billion." According to the researchers, this cost could be offset by a projected "$3 billion in savings in the management of chronic HCV and advanced liver disease," presumably because so many people would have received treatment and would be cured and not require hospitalization.
The UCSF team also made the following statement:
"Market or political forces may result in significantly decreased drug costs in the next several years, and a subset of patients, given the slow progression of HCV, may be treated at a lower cost without a risk for serious clinical progression."
For the Future
The work of the different research teams involved in trying to envision and calculate the scale and cost of interventions needed to effect massive change on the HCV epidemic is important. Other researchers need to confirm the robustness of the mathematical models reported here and make refinements if necessary. Now policy planners, health system administrators and other stakeholders can begin to consider and debate the bold steps needed to make the HCV epidemic history.
Our next CATIE News bulletin focuses on work using data from British Columbia, where researchers ran simulations of programs and services that may be necessary to greatly reduce the burden of HCV infection.
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