Johnson tells MTV that, "It was [something that I was going to do] for a minute, but then it kind of just went away, as things happen in Hollywood. For a minute, I was interested in it, but then it went away."
Regarding the "went away" part, we know that producer Joel Silver was attached to the Lobo movie with director Brad Peyton, but Silver had a falling out with Warner Bros. and left the studio, and we haven't heard about Lobo since.
Currently, Dwayne Johnson is set to play Hercules next in the movie of the same name as well as having G.I. Joe Retaliation, Fast and Furious 6 and further appearances on WWE and Wrestlemania in the works.