The largest study was designed to determine the effectiveness
of an 8-week regimen in people who met the FDA criteria, and to identify
predictors of relapse.
The analysis pooled data from four cohorts: Burman’s
Pharmacy (n = 307), Kaiser Permanente Southern California (n = 203), the Institute
for Interdisciplinary Medicine (Hamburg) (n = 126) and HCV Trio (n = 232). The HCV Trio
network includes academic and community-based clinics throughout the United
The analysis excluded anyone treated with ribavirin and
those lacking recent fibrosis staging information, as well as those treated
post-transplantation. The analysis identified 868 people who received an
8-week course of sofosbuvir/ledipasvir, of which 798 people met the FDA
eligibility criteria. Sixty-one individuals were excluded from the per-protocol
analysis on the grounds that they had baseline viral loads above 6 million
The cohort was evenly comprised of men and women, 62.7%
white, 25% African-American and 10% Hispanic. Approximately two-thirds of
people had genotype 1a infection and the vast majority had less advanced
fibrosis (F0-F2) (82.7%).
The per-protocol analysis showed that 98.5% of people
treated according to FDA guidance achieved sustained virological response (SVR12). Sub-group analysis showed
that at least 95% of people achieved SVR12 in all sub-groups, and logistic
regression analysis found no variables associated with relapse.
All 61 individuals with baseline viral load above 6 million
IU/ml achieved SVR12.
A separate systematic review by the same group identified
six additional studies reporting comparative outcomes in people treated with
sofosbuvir/ledipasvir for 8 or 12 weeks. The pooled population
comprised 5637 people and per-protocol SVR12 rates were 95.8% in those treated
for 8 weeks and 97.2% in those treated for 12 weeks, a non-significant
difference. There was no significant difference in the risk of viral relapse.