Spike Chunsoft has announced a follow-up title to Attack on Titan: Humanity in Chains called Attack on Titan 2: Future Coordinates for 3DS. It is scheduled to come out this year in Japan, but still no information about a western release, let alone a release date. You can visit the teaser site by clicking here.
The previous game had some pretty lukewarm reviews, so hopefully there are improvements made that make the follow-up more appealing. The console/PC Attack on Titan game from Koei Tecmo and Omega Force is viewed much more favorably (including myself), so Spike Chunsoft has a lot to prove to make this one worth it for fans.
Source: Spike Chunsoft