1 The Kirby Institute, UNSW Sydney, Sydney, Australia.
2 Faculty of Medicine and Health Sciences, Macquarie University, Sydney, Australia.
3 University of South Carolina-Greenville, Greenville, SC, USA.
4 Clemson University, Greenville, SC, USA.
5 Prisma Health, Greenville, SC, USA.
6 Auckland City Hospital, Auckland, New Zealand.
7 Ottawa Hospital Research Institute, Ottawa, Canada.
8 Inserm UMR-S1136, Sorbonne Université, Hôpital Saint-Antoine, AP-HP, Paris, France.
9 The Burnet Institute, Melbourne, Australia.
10 Department of Infectious Disease, The Alfred Hospital, Melbourne, Australia.
11 Kirketon Road Centre, Sydney, Australia.
12 South Riverdale Community Health Centre, Toronto, Canada.
13 Akershus University Hospital, Oslo, Norway.
14 Institute of Clinical Medicine, University of Oslo, Oslo, Norway.
15 Centre Hospitalier de l'Université de Montréal, Canada.
16 St Vincent's Hospital, Sydney, Australia.
17 Toronto General Hospital, Toronto.
18 Ninewells Hospital and Medical School, University of Dundee, Dundee, United Kingdom.
19 Royal Adelaide Hospital, Adelaide, Australia.
20 Arud Centres for Addiction Medicine, Zurich, Switzerland.
21 Vancouver Infectious Diseases Center, Vancouver, Canada.
22 Coolaid Community Health Centre, Victoria, Canada.
This study investigated treatment adherence and associated factors among people with recent injecting drug use or current opioid agonist therapy (OAT) and compared once-daily to twice-daily DAA therapy.
SIMPLIFY and D3FEAT are international, multicentre studies which recruited participants with recent injecting drug use (previous six months; SIMPLIFY, D3FEAT) or current OAT (D3FEAT) between March 2016 and February 2017 in eight countries. Participants received sofosbuvir/velpatasvir (once-daily; SIMPLIFY) or paritaprevir/ritonavir/ombitasvir, dasabuvir (twice-daily) ±ribavirin (D3FEAT) for 12 weeks administered in electronic blister-packs. We evaluated overall adherence (proportion of prescribed doses taken) and non-adherence (<90% adherent) with comparisons between dosing patterns.
Of 190 participants who commenced treatment, 184 (97%) completed treatment. Median adherence was 92% with higher adherence among those receiving once-daily vs. twice-daily therapy (94% vs. 87%, P=0.005). Overall, 40% of participants (n=76) were considered non-adherent (<90% adherent). Recent stimulant injecting (odds ratio [OR] 2.48, 95% confidence interval [CI] 1.28-4.82), unstable housing (OR 2.18, 95% CI 1.01-4.70), and receiving twice-daily dosing (OR 2.81, 95% CI 1.47-5.36) were associated with non-adherence. Adherence decreased over the course of therapy SVR was high in non-adherent (89%) and adherent populations (95%, P=0.174) with no difference in SVR between those who did and did not miss at least seven consecutive doses (92% vs 93%, P=0.897).
This study demonstrated high adherence to once- and twice-daily HCV DAA therapy among people with recent injecting drug use or were currently receiving OAT. The levels of non-adherence described did not impact treatment outcomes, suggesting forgiveness to non-adherence.