AbbVie’s QUARTZ-1 study examined the impact of adding
sofosbuvir and ribavirin, or sofosbuvir alone, to its Viekira Pak /Viekira &
Exviera regimen. The open-label study recruited 22 participants who had
experienced viral failure or relapse after first-line treatment with a variety
of regimens, not restricted to AbbVie’s own combination. Participants were assigned
- Genotype 1a, no cirrhosis (n = 14): 12 weeks of
treatment with ombitasvir, paritaprevir/r and dasabuvir, plus sofosbuvir and
- Genotype 1a, cirrhosis (n = 6): 24 weeks of treatment
with ombitasvir, paritaprevir/r and dasabuvir, plus sofosbuvir and ribavirin.
- Genotype 1b, with or without cirrhosis (n = 2): 12
weeks of treatment with ombitasvir, paritaprevir/r and dasabuvir, plus
Paritaprevir levels are boosted by ritonavir.
All participants with genotype 1a and cirrhosis had been
treated previously with ombitasvir, paritaprevir/r and dasabuvir. Ten out of 14
genotype 1a participants without cirrhosis had received ombitasvir,
paritaprevir/r and dasabuvir (8) or ombitasvir and paritaprevir/r (2). Four of
the remaining six had received an HCV protease inhibitor in combination with
either sofosbuvir or an experimental agent
Those receiving treatment for 12 weeks had the option of
continuing treatment for a further 12 weeks if HCV was still detectable at week
12. In the event one participant with genotype 1a infection received extended
Twelve weeks after the completion of treatment 14 of 15
participants who had received 12 weeks of treatment had a sustained virological
response (SVR12). One participant experienced virological relapse; this patient
had no evidence of baseline resistance.
In those who received 24 weeks of treatment post-treatment
virologic data to week 4 (SVR4) show no cases of virological relapse.
Over half of participants had at least one mutation associated
with resistance to NS3 protease inhibitors, and over half had at least one
mutation associated with resistance to NS5A inhibitors.
The single virological failure occurred in a participant
previously treated with telaprevir (a first-generation HCV protease inhibitor),
pegylated interferon and ribavirin.