It’s not easily supported. Here’s an article with instructions on how to pass EventArgs as command parameters.
You might want to look into using MVVMLight – it supports EventArgs in command directly; your situation would look something like this:
<i:Interaction.Triggers>
<i:EventTrigger EventName="Navigated">
<cmd:EventToCommand Command="{Binding NavigatedEvent}"
PassEventArgsToCommand="True" />
</i:EventTrigger>
</i:Interaction.Triggers>