How to delete a pattern from String?

Having a string like :

"{Aaaa -> a, Bbbb- > b, Cccc -> , Ddddd -> c, Eeeee -> , Fffff -> e}"

I want to delete the parts that contain "a word"+"-> ," and replace them just with "," to have result like

"{Aaaa -> a, Bbbb- > b, Ddddd -> c, Fffff -> e}"

So that I can bring this ToExpression[]

Thanks.