DAX time intelligence functions - no "weekly" options

DAX  time intelligence functions appear to be able to deal with days, month, quarters and year, but not weeks e.g.

• there are NEXTDAY, NEXTMONTH, NEXTQUARTER and NEXTYEAR functions but no NEXTWEEK; 
• DATEADD interval can be year, quarter, month, day but not week

Are there any workarounds that could facilaite doing comparisons between this week's sales & last week's, for example?

Thanks!