The cost-effectiveness of curing hepatitis C virus relative to managing the chronic illness has been argued, and now pharmacoeconomic comparisons may have identified the most cost-effective treatment regimen.
A new cost-effectiveness study has distinguished between the 6 oral direct acting antiviral (DAA) regimens recommended for treating chronic hepatitis C virus (HCV) genotype 1 infection and the 4 regimens for treating genotype 4.
This comparison is a departure from previous economic models — which the researchers found to have compared costs of curing versus managing chronic illness, involved only selected agents, contrasted new with older regimens, or included comparators not subsequently available or not recommended in treatment guidelines.
"We felt that one limitation to many published cost-effectiveness studies was the way a new breakthrough drug was being compared in many cases to old therapy or not treatment at all," Joseph Mattingly (pictured), PharmD, MBA, Department of Pharmacy Practice and Science, University of Maryland School of Pharmacy, said. "We wanted to build a model that compared all recommended first-line treatments, rather than compare one of them against older, interferon-based regimens that are no longer first-line."
Mattingly and colleagues developed an economic model that incorporated the natural history and progression of chronic HCV genotypes 1 (types a and b) and 4, and compared outcomes of the recommended treatment strategies from clinical trials. The model assumed patients are treatment naїve and without cirrhosis, and that treatment was maintained for the recommended 12 weeks. Efficacy is based on sustained virologic response (SVR) at one year.
The model included probability calculations for disease progression, with patients reaching SVR in one year subject to conservative estimation of mortality rate, but without probability of reinfection. The proportion of patients that data indicate do not achieve SVR were entered into a progression process with baseline fibrosis and subsequent severity staging.
Care costs were derived from amounts spent at state level for patients with virologic cure but having sustained liver damage, or for those without SVR presenting advanced disease.
Relative drug costs were based on wholesale acquisition cost (AWC), with multiple analysis conducted with costs ranging from 50% AWC to 100% AWC to account for potential discounting in managed care and direct manufacturer contracting. Health care costs were adjusted for health-related quality of life, with additional quality-adjusted life years (QALYs) following treatment as the main model outcome.
Mattingly and colleagues calculated that the DDA regimens were comparably effective, associated with between 18.08 and 18.40 QALYS for genotype 1 and 18.23 to 18.43 QALYs for genotype 4.
The combination of grazoprevir/elbasvir (Zepatier, Merck) was the least costly of 6 combination DAAs for genotype 1, at $88,107 in a range that topped at $184,636. It was also the least costly of the four regimens for genotype 4, at $87,063 in a range that went as high as $127,637.
"Despite the high costs, DAAs offer an enormous public health benefit," Mattingly said. "Therefore, one policy question is which DAA provides the greatest value. A comparative cost-effectiveness analysis provides insights for addressing the most value-based approach to DAA coverage and treatment."
The study, "Hepatitis C Treatment Regimens Are Cost-Effective: But Compared With What?" was published online in Annals of Pharmacotherapy last month.