One problem with deploying Office 365 in security-conscious corporate environments is that you have to rely on unsecured public connections to the Web-based aspects of the platform. Microsoft has announced plans to allow businesses to use its ExpressRoute service to create a private managed connection to Office 365.
In a blog post, Microsoft said the option would become available in the third calendar quarter of 2015. That means it will almost certainly appear before the next major Office upgrade, Office 2016.
No details yet on pricing. Right now, Microsoft is offering a free 10Mbps ExpressRoute circuit, a deal which expires at the end of June.
Announcing Azure ExpressRoute connectivity to Office 365 [Office 365 Blog]