Hepatitis C could be reduced by 90% or more in the United States by the year 2040 with the use of direct-acting antivirals, near-universal screening, and enhanced treatment capacity, according to a study in Clinical Infectious Diseases.
A research team led by Jeffrey Townsend, Ph.D., of Yale School of Public Health, New Haven, Conn., said that new direct-acting antivirals (DAAs) alone could reduce the prevalence of hepatitis C virus (HCV) by 80% by the year 2040. When near-universal screening and enhanced treatment capacity are added to the equation, HCV could be eliminated in the United States, though cost and reimbursement issues may impede implementation.
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“The key finding is that a fourfold increase to the number of patients treated each year could virtually eliminate HCV from the noninjecting population within a decade,” said Dr. Townsend, senior author of the study, in a statement accompanying the study [Clin Infect Dis. 2015. doi: 10.1093/cid/civ894].
First author David Durham, Ph.D., also of the Yale School of Public Health, and his collaborators analyzed currently available data and constructed a sophisticated model to generate projections of how future DAA treatment will change HCV prevalence. Dr. Durham and his colleagues also built models to account for varying levels of screening in the general population and for people who inject drugs (PWIDs).
More than 5 million people with chronic hepatitis C infection are thought to live in the United States, and just about 100,000 of those currently receive treatment each year. The treatment burden and relatively low cure rate of interferon-based therapies have historically been significant impediments for many patients. New DAAs promise a sustained virologic response (SVR) in up to 95% of patients with a well-tolerated, once-daily, one-pill several-week regimen.
Without enhanced screening or treatment rates, the model predicted an 80% decline in U.S. HCV prevalence by the year 2040. The 80% benchmark would be reached by the year 2025 if the annual treatment rate increased to 400,000, with 256,315 fewer HCV-related deaths through 2040. Just doubling the treatment rate to 200,000 patients per year would result in an 80% decrease in HCV prevalence by 2031, with 143,055 fewer deaths by 2040.
However, “more than half of those with chronic HCV are unaware of their status, including up to two-thirds of people who inject drugs,” wrote Dr. Durham and his coauthors. Therefore, enhanced HCV screening, especially among PWIDs, could provide a significant further reduction in morbidity and mortality from HCV.
Targeted screening of PWIDs to achieve a 20% screening rate (compared with the current 4.1%), combined with a treatment rate of at least 30%, would yield a 90% reduction of prevalence in HCV by 2040. Universal screening, combined with a treatment rate of at least 20%, would achieve a 90% reduction in the incidence of new infections by 2040, according to the model.
The drop in prevalence in the models took into account not only an increased SVR rate, but also the reduced transmission rate when more persons with HCV achieve an SVR. This dynamic transmission analysis “captures the impact of treatment on both chronic disease and transmission dynamics, distinguishes screening and treatment as separate but related public health objectives, and accounts for underreporting … of national HCV prevalence,” according to Dr. Durham and his coauthors.
Morbidity and mortality were accounted for by projecting the number of HCV patients in each treatment and screening condition who would spontaneously clear disease, become chronically infected, develop increasing levels of liver disease and cirrhosis, require transplant, become reinfected, or die.
As always, real world considerations temper what’s achievable. For DAAs, a chief factor is the cost of the regimens, which currently hovers around $90,000. “The improvement of health outcomes expected from greater acceptance might be tempered by the high costs of treatment and by limited insurance coverage and willingness to treat PWIDs,” Dr. Durham and his coauthors wrote.
Study limitations included some “simplifying assumptions” in the modeling, which did not account for the varying incidence of fibrosis and transmissibility among different HCV genotypes. Still, wrote Dr. Durham and his collaborators, “our analysis provides a forecast for the potential impact of DAAs in reducing HCV-associated liver disease, demonstrating that achievable expansion of HCV treatment at current screening rates can substantially reduce morbidity and mortality.”
The study was funded by the Notsew Orm Sands Foundation and Merck. Dr. Durham, Dr. Galvani, and Dr. Townsend have consulted for and received research funding from Sanofi Pasteur and Merck. Dr. Elbasha is employed by Merck and holds stock and stock options in the company. The other authors reported no conflicts of interest.