German approval could be effective EU approval.
Working in electrical years ago, there were two important European approvals for components, (Circuit breakers, current monitors, UPS's, etc.). There was VDE (German) and CE (EU). The VDE approval was the technical safety approval and the CE "Mark" was primarily a trade approval, not a technical approval, as I understood it.
VDE approval was good enough for everybody in Europe. There wasn't a French approval, or an Italian approval... they didn't need it.
DCVax-L just got an effective VDE approval... sort of. They are now negotiating pricing and somebody said this pricing will set the price throughout Europe. So they are currently negotiating the business part of things... sort of like the CE mark.
Not sure drugs/therapies would behave similar to electrical components... but if they do, there may not need to be a bunch of trials in other countries in Europe.
Even if other countries require there own stamp on medical... how long would you spend sorting through the data with the German's already having approved it and your citizens travelling to Germany to get treatment?