The present invention relates to compositions comprising complexes that are formed by polyinosinic-polycytidylic acid with a polyalkyleneimine, such as polyethyleneimine, that present uniform structural and functional features, as well as to processes for the preparation of said compositions that comply with regulatory requirements. The present invention additionally relates to use of said compositions as medicaments (in particular for treating cancer), alone or in combination with other therapeutic agents and/or in specific medical methods. Moreover, the administration of these compositions is associated to changes in the expression of specific genes, in cell responses, and/or in composition of immune cell populations that can be used as specific biomarkers and/or as additional target for medical treatment.
