Before Kamandi... Before Planet of the Apes... There was - Mighty Samson!
Otto Binder, whose contributions to comics and SF are way to numerous to go into at length here, but include most of the Fawcett Captain Marvel stories of a more enjoyable nature, Adam Link, numerous science fiction books and stories as Eando Binder, Bizarro and much more created Mighty Samson for Gold Key, and along with Magnus and Dr Solar formed the heavy hitting triumvirate of that publishers original SF influenced superhero characters. First drawn by Frank Thorne, with Jack Sparling taking over after the first half dozen issues, Samson existed in a post-apocalyptic world filled with mutant creatures, atom-blasted buildings and a generally devolved caveman-like populace.
When I first saw Kamandi (and don't get me wrong, I loved Jack Kirby's post "Disaster" epic), my first thought was that it was a cross between Planet of the Apes and Mighty Samson. Sure ol' Samson slowly gets a little on the goofy side in later issues (such as Issue 9), but some of the earlier issues by Frank Thorne are just amazing! Issue 3, available below, is especially tasty!
And the covers! As you may know, the early Gold Key covers were reprinted on the back of the book without text as a "Pin-Up Page". These blew my mind as a kid, and still leave me gobsmacked as an adult. Most of these amazing paintings were done by Morris Gollub or George Wilson, mostly unknown artists who did incredible work that made the Gold Key books look very different on the comic stands of the 60's.
When Valiant purchased most of Gold Key's characters in the 80's, Samson wasn't among them. Thank goodness for that!
Mighty Samson #3
Mighty Samson #9