There are some well-sourced rumblings out there that DC is ending its First Wave line. The First Wave books centered around several pulp heroes, including Doc Savage, The Spirit, the Blackhawks, and Rima the Jungle Girl.
The reason isn’t entirely clear, but the standalone DOC SAVAGE and SPIRIT books were selling below 10K copies, which is well into the danger zone on today’s comics.
First Wave was spearheaded by writer Brian Azzarello a few years ago as a way to expand the DC Universe with some classic adventure characters. The line kicked off with a Batman/Doc Savage team-up and has continued with a First Wave miniseries by Azzarello and Rags Morales which just wrapped up. JG Jones was recently announced to be taking over the DOC SAVAGE book, and he sounded pretty enthused, so it would be a shame if this is true.
UPDATE: This is now being reported and speculated upon in many places. There is some indication that there may be a rights situation involved, as well as low sales.