A 24-week regimen of sofosbuvir (Sovaldi) plus ribavirin cured 93% of
people with hard-to-treat hepatitis C virus genotype 4, though treatment for
only 12 weeks was not as effective, according to a poster presented at the 49th annual meeting of the European Association for the Study of the Liver (EASL), held recently in London.
Genotype 4 – the predominant type in Egypt and several
other countries in Africa and the Middle East – accounts for approximately 20%
of hepatitis C virus (HCV) infections worldwide, and it is becoming more common
amongst newly diagnosed people in Europe. Like genotype 1, genotype 4 has
traditionally been considered difficult to treat compared to genotypes 2 and 3.
Most direct-acting antiviral agents (DAAs) have only been tested in small
numbers of people with genotype 4 and some have shown minimal activity against
Peter Ruane of Ruane Medical and Clinical Research Institute in Los
Angeles and colleagues evaluated an interferon-free
dual regimen combining the nucleotide HCV polymerase inhibitor sofosbuvir plus
ribavirin for people with HCV genotype 4.
The NEUTRINO study previously showed that sofosbuvir
plus pegylated interferon and ribavirin produced a cure rate of 96% for the 28 enrolled
treatment-naive participants with HCV genotype 4. Sofosbuvir plus ribavirin
without pegylated interferon for 12 weeks cures almost all patients with HCV
genotype 2, but the VALENCE trial showed that 24 weeks works better for genotype 3. This dual
regimen cures a substantial proportion of easier-to-treat patients with HCV genotype
1, but sofosbuvir works better against this genotype when combined with another DAA such as ledipasvir.
This single-centre phase 2b trial included 60 people born in Egypt and
living in the US. About 70% were men and the mean age was 54 years. Just under
half had not taken treatment for HCV before (treatment-naive), most of whom were deemed ineligible to use
interferon. The rest had previously been treated with interferon-based therapy,
including relapsers, non-responders and those who stopped due to intolerance.
Most (about 80%) had unfavourable IL28B non-CC gene variants, nearly
one-quarter had compensated liver cirrhosis and about 40% had previously had
schistosomiasis (a parasitic infection that can cause liver damage).
Participants in this open-label study were randomly assigned to receive
400mg sofosbuvir once daily plus 1000-1200mg/day weight-based ribavirin for
either 12 or 24 weeks. The primary endpoint was sustained virological response
or undetectable HCV RNA at 12 weeks after finishing treatment (SVR12),
considered to be a cure.
All participants completed treatment. SVR12 rates were 68% in the
12-week treatment arm, rising to 93% in the 24-week arm. Among previously
untreated participants, the 12- and 24-week SVR12 rates were 70% and 100%. Among
treatment-experienced patients, cure rates were 59% and 87%, respectively.
Among treatment-naive participants treated for 12 weeks, people with
cirrhosis had a lower SVR12 rate than people who did not have cirrhosis (33 vs 91%), but
responses were similar in the other treatment arms. IL28B non-CC status was
also associated with poorer response in the 12-week arms.
All virological failures were due to post-treatment relapse, and there
were no cases of viral breakthrough while on therapy. The S282T sofosbuvir
resistance mutation was not detected at baseline or in any of those who
experienced treatment failure.
Sofosbuvir plus ribavirin was generally safe and well-tolerated. There
were three serious adverse events in the 24-week arm. One person in this group
discontinued ribavirin early due to an adverse event and continued on
sofosbuvir monotherapy. The most common side-effects were headache, insomnia
and fatigue. No participants developed severe anaemia, though four people (14%)
in the 24-week arm had mild anaemia (haemoglobin <10g/dL).
"Sofosbuvir + ribavirin provides a simple, interferon-free regimen
for patients with HCV genotype 4," the researchers concluded. "Treatment-naive
patients had higher SVR12 rates following treatment for 12 or 24 weeks than did
treatment-experienced patients. Extending treatment duration to 24 weeks
increased SVR rates, particularly for treatment-experienced patients."