Provided is the use of a muramyl dipeptide (MDP)/DNA microparticle for the manufacture of a medicament for treating neoplastic disease, The microparticle can be combined with an immunostimulatory ligand bound to or within the microparticle or with antineoplastic agents or anti-tumour vaccines. The compositions stimulate tumour specific immune responses, including potentiating NK and/or NKT cell activity or the release of cytokines, chemokines and cytotoxic proteins.
