Run exe in custom URI protocol silent

I have registered a custom protocol handler in registry which is going to open files and directories from a SQL-Server FileTable Share on browser interactions. Everything works fine and the .exe is doing what it should be doing.

Unfortunately everytime I do this (originally .bat but stored as exe with @echo off) a command prompt windows pops up and stays until the exe finished its job.

Is there a possibility to pass the exe a specific parameter in registry to avoid the window and run silently? Heres my Handler: "C:\Program Files (x86)\Document Handler\openSharedDirectory.exe" %1

I've already tried something like /r.

Thanks in advance.