A Comcast spokesman also said the venture had been dissolved.
Though said to be based in Philadelphia, most of the development took place at Verizon's headquarters in Central New Jersey and involved several hundred employees.
"While Verizon Wireless and Comcast decided to end the joint product-development venture, we continue to offer each other's products and services," the Comcast spokesman said. "As always, Comcast remains committed to bringing a steady flow of new innovations, like X1 and our wireless gateways, to our customers, and to work every day to deliver a great user experience."
As part of the 2011 spectrum deal, Comcast and Verizon Wireless agreed to jointly market their products in Verizon Wireless and Xfinity stores, and to develop new products.
In late 2011, Verizon Communications owned 55 percent of Verizon Wireless and England's Vodafone Group owned the other 45 percent.
Last year, Verizon Communications agreed to purchase the 45 percent of Verizon Wireless it didn't already own, and this may have changed the complexion of the Comcast/Verizon Wireless relationship. While Verizon Wireless does not directly compete with Comcast, Verizon Communications does, with FiOS TV and FiOS Internet.
Both Comcast and Verizon Communications, moreover, are looking at broadening their video-streaming capabilities.
Comcast and Verizon Communications considered acquiring Intel Corp. media assets in recent months. Verizon announced Tuesday that it had agreed to purchase those assets.
Comcast has boosted its research budget and hired about 1,000 software engineers. Its research and development employees, now scattered in the Comcast Center and leased offices in Center City, are expected to relocate to the proposed second Comcast tower when it opens in 2017.