Hi, 

the Chesspub E-book says: "A good way for black to avoid mainlines". It has 4.dc5 as the main move, but also mentiones 4.Bd3 cd4 followed by Nc6, Bg4. 

I had a look at the online games of newinchess.com and strong players also tried 4...Qc7 (Cheparinov, Cifuentes, Polgar,...) which keeps all options. Black will follow up with g6, Bg7 and 0-0. White has a strong pawn center, but blacks setup looks flexible "pirc"- and "kingsindian"-like. As nothing is exchanged early this line could be a nice way to meet the c3-siclian.

Thanks for mentioning it.