I found the case-based workshop on HCV quite useful. The session highlighted some of the difficult therapeutic scenarios with current DAAs. It also mentioned some of the limitations of current DAAs and research gaps in this area.
Here I have summarised important points relevant to HIV & HCV prescribers. Standard abbreviations are used.
HIV and HCV co-infection
Even though efficacy of current DAAs in HIV/HCV high and generally equivalent to HCV mono-infections, this is still a "special" population with therapeutic challenges
DDI with HIV ART
LDV/SOF with TDF increases tenofovir plasma concentrations; greater effect when combined with RTV boosted PIs. Avoid LDV/SOF if CrCl< 60 or with TDF+ RTV-boosted PI
However, the clinical significance of elevated TDF level here is not very clear at this stage. But when LDV/SOF and TDF given, frequent monitoring recommended eg week 2 & 4 renal functions monitoring
What about TAF and LDV/SOF? Data was presented for E/C/F/TAF and R/F/TAF. Tenofovir concentration are increased but well below the concentrations with TDF.
Take home message: LDV/SOF and TDF: Be aware contra-indications and frequent renal function monitoring while on DAAs
DDI with other meds
One important DDI highlighted in the case was PPIs and SOF/LDV. Chronic PPI therapy is not uncommon in PLHIV and in many cases, it is unnecessary. There is significant decrease of LDV concentrations with PPIs. The data from HCV TARGET study sub-analysis was presented. SVR 12 with SOF/LDV was reduced from 90% to 70% when PPIs are used as baseline.
Take home message: PPIs can significantly compromised SOF/LDV efficacy. This is good opportunity to review patients on long term PPIs and cease if not absolutely necessary. One more reason to stop unnecessary long term PPIs
Can we stop HIV treatment temporarily when there are significant DDIs with HIV ART and HCV DAAs? Panel members felt with the available of new HIV ARTs, stopping HIV treatment temporarily is not acceptable and it’s recommenced to change HIV ART to a suitable regimen prior to HCV DAA treatment.
Shorter course of DAAs
In some subpopulations, SOF/LDV and SOF/DCV 8 weeks has high efficacy comparable to 12 weeks treatment.
For an example, In GT1, treatment naive, non-cirrhotic and baseline HCV VL less than 6 million IU/mL treatment can be shorted to 8 weeks of SOF/LDV.
However, data is currently not available for HIV/HCV co-infections. The panel members recommendation was until we have more data for co-infections, avoid 8 weeks treatment.
Take home message: Avoid shorter course (less than 12 week ) of SOF/LDV or SOF/DV in HIV/HCV co-infections until more clinical data available.