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Sofosbuvir-Based Regimens for Chronic Hepatitis C in a Well-Insured U.S. Population: Patient Characteristics, Treatment Adherence, Effectiveness, and Health Care Costs, 2013-2015.

BACKGROUND
Chronic hepatitis C (CHC) is a leading cause of morbidity and mortality and has imposed a high health care burden in the United States. Direct-acting antiviral (DAA) regimens are well tolerated and highly effective for CHC therapy but were initially marketed at a high price. Studies of their real-world use with a nationwide population are limited.


OBJECTIVE
To examine patient characteristics, treatment adherence, effectiveness, and health care costs in a large U.S. population with commercial and Medicare supplemental insurance plans who received simeprevir (SIM), sofosbuvir (SOF), or ledipasvir/sofosbuvir (LED/SOF) during the years 2013-2015.


METHODS
Patients with at least 1 diagnosis code for CHC and at least 1 claim for SIM, SOF, or LED/SOF prescriptions were selected. The date of the first claim for SIM, SOF, or LED/SOF was defined as the index date. Analyses were stratified by 4 regimens: SOF + SIM ± ribavirin (RBV), SOF + peginterferon alpha-2a or 2b (PEG) + RBV, SOF + RBV, and LED/SOF ± RBV. Adherence was defined by the proportion of days covered (PDC) ≥ 80%. Sustained virologic response (SVR12) was defined as a hepatitis C virus (HCV) RNA load of ≤ 25 IU/mL measured at ≥ 12 weeks following the end of the days supply of the last DAA refill. Health care costs such as DAA drug costs and medical costs (inpatient costs plus outpatient costs) were described.


RESULTS
Of 10,808 CHC patients, approximately two thirds were male, and mean age was 55 years. The proportion of patients with compensated cirrhosis among each regimen ranged from 7.4% in LED/SOF ± RBV to 13.8% in SOF + SIM ± RBV, and the proportion of patients with decompensated cirrhosis ranged from 3.9% in LED/SOF ± RBV to 10.7% in SOF + SIM ± RBV. The majority of patients (89.0%) used the newer regimen LED/SOF ± RBV in 2015. Adherence rates were estimated at 80.5%, 81.5%, 85.7%, and 91.4% for SOF + SIM ± RBV (n = 1,761); SOF + PEG + RBV (n = 1,314); SOF + RBV (n = 1,994); and LED/SOF ± RBV (n = 5,739), respectively. Regimen-specific adherence predictors included sex, age group, payer type, health plan, and treatment option with RBV. Being born during 1945-1965, liver disease severity, and Charlson Comorbidity Index levels did not predict adherence in any regimen. Overall SVR12 was 92.6% in 203 patients with available HCV RNA results: 100% (41/41) in SOF + SIM ± RBV; 83.3% (25/30) in SOF + PEG + RBV; 90.6% (29/32) in SOF + RBV; and 93% (93/100) in LED/SOF ± RBV. While the drug costs for these DAA regimens were initially high, they had decreased 18.9% (P < 0.001) during 2013-2015. Medical costs decreased 9.2% (P < 0.001) 1 year after the index dates.


CONCLUSIONS
These results indicate that DAA drug costs decreased steadily during 2013-2015 and that 89% of patients on SOF-based DAA regimens took newer, lower-cost regimens with adherence rates above 80%. Available data show that SVR12 rates were close to those obtained in clinical studies. Medical costs also significantly decreased 1 year after the index dates.


DISCLOSURES
No outside funding supported this study. All authors are U.S. federal employees of the Centers for Disease Control and Prevention. The authors declare that they have no competing interests. The findings and conclusions in this research are those of the authors and do not necessarily represent the official position of the Centers for Disease Control and Prevention.