Burroughs sold Lesser options on all his Tarzan novels for seven years with Lesser producing one Tarzan film a year for 20th Century Fox. Only one Tarzan film Tarzan's Revenge featuring athletes Glenn Morris and Eleanor Holm was produced; Lesser sold the rights back to MGM.
Burroughs granted Lesser the right to produce Tarzan films based on his novels for seven years.  Lesser produced one Tarzan film annually during that time, with only "Tarzan's Revenge" being released.  After this period, Lesser sold the rights back to MGM.