With about half of people with genotype 1 able to take just eight weeks of Gilead Sciences’ Harvoni (ledipasvir/sofosbuvir), the race is on to best this treatment length or offer it to more genotypes.

Gilead tested six weeks of a fixed-dose combo pill of Sovaldi (sofosbuvir) and a drug called GS-5816, plus GS-9857 (both the latter agents are experimental) among people with genotype 1 of hep C in a recent small trial. Among participants treated for the first time, 93 percent of those without cirrhosis and 87 percent of those with cirrhosis were cured. Just 67 percent of those who’d failed a previous cure attempt succeeded with this treatment.

In another small trial of Merck’s combo of grazoprevir/ elbasvir (up for FDA approval as of press time) plus Sovaldi, eight weeks of treatment worked well among people with genotype 1 or 3 who were treated for the first time. Among people with genotype 1, 94 percent of those with cirrhosis were cured after eight weeks, and 87 percent of those without cirrhosis beat hep C after six weeks. Eight weeks cured 93 percent of those with genotype 3 without cirrhosis, while 12 weeks cured everyone in this demographic and 91 percent of genotype 3s with cirrhosis.