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Shortening hepatitis C treatment to 6 weeks effective but not perfect for easier-to-treat patients
Keith Alcorn, 2015-05-15 07:20:00

Shortening hepatitis C treatment to 6 weeks for easier-to-treat patients without cirrhosis does not greatly reduce the efficacy of hepatitis C treatment for people with genotype 1 infection, according to results of a study combining grazoprevir, elbasvir and sofosbuvir in short treatment courses

Moreover the study showed that for people with genotype 3 hepatitis C but no cirrhosis, an 8-week course of treatment was only marginally less effective than a 12-week course, even though genotype 3 infection is considered harder to treat.

The findings of the C-SWIFT study were presented to the International Liver Congress in Vienna last month by Dr Fred Poordad of the Texas Liver Institute, University of Texas. Preliminary findings were presented previously at the American Liver Meeting in November 2014.

C-SWIFT is a proof-of-concept study designed to test whether the use of an especially potent regimen of grazoprevir (an HCV protease inhibitor) and elbasvir (an NS5A inhibitor) being developed by Merck, plus Gilead’s NS5B polymerase inhibitor sofosbuvir (Sovaldi), could shorten the duration of treatment for people with genotypes 1 or 3 hepatitis C.

The study tested treatment durations of 4, 6 or 8 weeks in genotype 1 patients, and 8 or 12 weeks in genotype 3 patients. Genotype 3 is considered harder to treat than genotype 1. The study recruited previously untreated people with hepatitis C genotypes 1 or 3 and liver enzyme (ALT and AST) levels below 350 IU/ml.

Participants in the study were randomised according to the following protocol:


Genotype 1

Genotype 3






Randomised to:

duration of treatment (n)

4 weeks (31)

6 weeks (20)

8 weeks (15)

12 weeks (12)

6 weeks (30)

8 weeks (21)

12 weeks (14)

A total of 143 patients were enrolled; 66% male, 98% white and 45% Hispanic. Of the genotype 1 patients, 82% had genotype 1a.

The primary efficacy analysis showed that a 4-week course of treatment in the non-cirrhotic performed very poorly. Just 33% of participants achieved a sustained virological response, compared to 87% of those treated for 6 weeks in the non-cirrhotic group and 80% in the cirrhotic group. 94% of cirrhotic participants treated for 8 weeks achieved a sustained virological response. No cases of viral breakthrough during treatment were observed. All but four treatment failures were cases of virological relapse; the remainder of treatment failures were due to treatment discontinuation.

In the genotype 3 group, an 8-week treatment course was marginally less effective than a 12-week treatment course among non-cirrhotic participants (93% vs 100% SVR12)), the difference being attributable to one case of virological relapse after completion of treatment. 91% of participants in the 12-week cirrhotic group achieved a sustained virological response. A per-protocol sub-group analysis of genotype 3 participants showed a trend towards poorer virological response in people with baseline HCV RNA > 2,000,000 IU/mL, but no other substantive differences in response.

The only serious adverse events occurred in the cirrhotic genotype 1 group. One participant discontinued treatment due to the development of B cell lymphoma after four weeks, and one developed pyelonephritis. No cases of liver enzyme or total bilirubin elevation were observed.

Giving an overview of conference presentations on viral hepatitis treatment on the final day of the conference, Professor Michael Manns of Hannover Medical School, Germany, said that when shortening treatment for the easiest to treat patients, C-SWIFT showed that 6 weeks appears to be the barrier below which efficacy falls off.

Merck will continue research into shorter regimens, composed of grazoprevir, the experimental nucleotide inhibitor MK-3682 and either elbasvir or the experimental NS5A inhibitor MK-8408, in genotypes 1, 2, 3 and 4.