The data is preliminary (from Stage 2 trials), but Gilead announced that sof/vel/vox is 99% effective for previous DAA failures of the studied classes (without naming the classes).
Source: GILEAD announcement on EASL Conference in April. It is also widely known that vox causes diarhea and is otherwise bad for your stomach in the short term. (See links below).
The data is from Stage 2 trials. So for retreatment of DAA-failures vox is a much much more effective option than say vel+sof for 24 weeks or with ribavirin. Vel is not good for retreament. It is recommended for treatment-naive people. Because it has almost no side effects and although there's no data yet if sof/vel/vox is effective for sof/vel relapsers, it is likely that this data is going to be available in the beginning of 2017.
If sof/vel/vox indeed proves effective against vel-resistant viruses, there's more probability to get cured if you do, say, sof+vel and if it doesn't work you do sof/vel/vox. Because sof/vel won't bring in any NS3 mutations and there's no data on retreatment of sof/vel/vox failures yet.
That said, if you're treatment-naive, get sof/vel. If DAA-experienced, wait a little. No data on if vox would help and in what situations it would (after which treatment regimens, in which liver conditions), but Stage 2 shows it is effective.
regist2.virology-education.com/2016/12co...ion/21_Sulkowski.pdf
www.natap.org/2016/EASL/EASL_31.htm
The problem is though, vox is not going to be available until mid-2017. It is effective in cirhotic populations.
Gen 1b
VL pre treatment 29000 ME/ml
AST 32 ALT 94, F0
Started treatment 13 January 2017
Generic sofosbuvir/velpatasvir (Incepta)
VL 9 days into treatment <300 (undetected)
AST 13.8 ALT 22
Side effects: mild dehydration, not a problem at all if I drink water at night, nothing to worry about
Diet and gastric ph are very important with velpatasvir. One must think what and when to eat to keep gastric pH low. Side effects disappeared 2 weeks after, unless I ate anything < 4hrs before the pill. SVR60.