Sony has confirmed its first-party studios are no longer working on PS Vita titles.

Sony Computer Entertainment SVP Masayasu Ito told 4Gamers (via DualShockers) that from here on out, all attention has been switched to PS4.
"Currently, first-party studios have no titles in development for PS Vita," he said. "Since third-parties are working very hard on PS Vita, SCE’s own strategy is to focus on PS4, which is a new platform.

“At the beginning the PS Vita did not resonate with age targets under 20, but now the situation is changing and the popularity with younger demographics is increasing. Minecraft: PS Vita Edition has provided a boost.

"In addition to that, a variety of third party games is also planned for the future, and in order to further accelerate that flow, we decided to release new colors for the PS Vita this fall.”