IL-7 was originally discovered by Immunex Corporation (now part of Amgen) and through a process of intellectual property acquisition resulting from several mergers, the compound eventually ended up at what is today Sanofi-aventis, from whom Cytheris holds the exclusive worldwide license. 

As the exclusive licensee, Cytheris holds all original patents protecting IL-7 and various uses including the use for T cell expansion and for enhancing humoral immunity.

In addition Cytheris has filed two patent applications protecting the purified protein as a drug substance for therapeutic use with the correct disulfide bridging, the appropriate glycosylation profile and polypeptidic purity. These patents also protect various hyperglycosylated analogs and various fusion proteins. These new patents will protect IL-7 and closed analogs until 2022 and 2025.