SAN FRANCISCO, CA—Non-adherence to antiviral regimens is predicted by the use of pegylated interferon or ribavirin, duration of treatment, and baseline and on-treatment patient-reported outcomes (PRO) scores, reported Zobair Younossi, MD, MPH, from Inova Fairfax Hospital, Falls Church, VA, at The Liver Meeting® 2015.

“Adherence to interferon-free ribavirin-free regimens exceeds 96%,” Dr. Younossi noted. 

Dr. Younossi and colleagues evaluated the impact of clinical and PRO factors on adherence to various anti-hepatitis C virus (HCV) regimens. PRO data for SF-36, CLDQ-HCV, FACIT-F, and WPAI:SHP from 13 clinical trials of anti-HCV treatment were included in the analysis. Researchers defined “treatment non-adherence” as less than 80% of doses taken for any of the drugs used.

Of the total 4,825 chronic hepatitis C patients whose data were included in the analysis, 64.7% were treatment-naive, 19.3% were cirrhotic, and 65.1% had HCV genotype 1 infections. 

Dr. Younossi reported that the studied regimens included:

·         Interferon (IFN) + ribavirin (RBV)-containing (IFN + RBV ± sofosbuvir [SOF]): 14%

·         IFN-free RBV-containing (RBV + SOF ± LDV): 52%

·         IFN-free/RBV-free (LDV/SOF fixed-dose combination): 31%

Study authors calculated the adherence for each drug to be: LDV/SOF fixed-dose combination (97.5%), SOF (95.1%), IFN (86.4%), and RBV (85.1%). 

Before treatment, non-adherent patients were more likely to be unemployed (48% vs. 39%; P<0.0001), to have a history of depression (32% vs. 26%; P=0.0047), and have a lower baseline PRO score (up to -5.3% lower; P<0.0001). 

“The greatest baseline PRO difference between adherent and non-adherent patients was in role physical and social functioning domains of SF-36,” reported Dr. Younossi. 

The lowest PRO scores and the largest decrements in PROs by the end of treatment were seen in patients non-adherent to IFN-containing regimens. 

“Similarly, modest PRO decrements were noted in patients non-adherent to IFN-free RBV-containing regimens with (up to -8.3%; P<0.0001),” Dr. Younossi reported. “In contrast, no significant declines in PRO scores were noted in 3.8% of patients who were non-adherent to LDV/SOF (all P>0.05).”

“Adherent patients had higher 12-week sustained viral response (SVR12) rates than non-adherent patients (P<0.002),” Dr. Younossi noted.

Factors associated with a lower likelihood of treatment adherence in multivariate analysis included a patient being treatment-naïve, having HIV/HCV co-infection, longer treatment duration, and receiving IFN-containing or IFN-free RBV-containing regimens, Dr. Younossi reported. In contrast, higher likelihoods of treatment adherence were associated with higher baseline physical well-being of FACIT-F, end-of-treatment bodily pain of SF-36, and social well-being of FACIT-F.