The new Leica APO-Summicron-SL 50mm f/2 Asph lens will be officially released on this August 15th. The price is expected to be around $4,000.
Some additional information:

• The APO-Summicron-SL-Lenses was designed from scratch for the mirrorless SL-System. That means that the optical and sensor design, as well as the imaging process, match perfectly to achieve the highest quality.
• Dual Syncro DriveTM Precision autofocus: The APO-Summicron-SL-Lenses focus from infinity to the closest focusing distance with exceptional speed and achieve absolute top performance ratings in the demanding professional camera segment.
• Design “Made in Germany”: Seals on the front element, the focusing ring, and the bayonet ensure that lenses mounted on the camera are exceptionally well protected against the ingress of light rain and particles of dust and dirt. In addition to this, Leica AquaDura® coating provides effective protection of the exposed surfaces of lenses against dirt and scratching for everyday use under the often extreme conditions of professional photography.
• The lens hoods of the SL-Lenses are ideally matched to each individual lens and prevent light from the sides entering the lens.

The Leica APO-Summicron-SL 50mm f/2 is the second SL lenses expected this year after the APO-Summicron-SL 35mm f/2 ASPH.
Here is the latest updated Leica SL lens roadmap: