Opportunistic infections in non-human primates exposed to immunomodulatory biotherapeutics: considerations and case examples.

Immunomodulatory biotherapeutics are most often evaluated for safety preclinically by way of repeat dose toxicity studies in non-human primates. Since immunomodulation is expected with this class of therapeutics, and since non-human primates share many opportunistic or latent infectious agents with humans, non-human primates in these toxicity studies may present with opportunistic or recrudescent infections that would be of concern if they occurred clinically in humans. In such instances, it is suggested that non-clinical safety assessment scientists consider a series of key questions that aim to clarify the relationship of the findings to the biotherapeutic under study and the expected predictivity of the findings to the human clinical setting. In this review, relevant case examples are considered comprising (i) gammaherpesviruses-mediated B-lymphocyte proliferation associated with a T-lymphocyte depleting fusion protein; (ii) increased plasmodial hemoparasite burdens associated with a monoclonal antibody inhibitory to T-lymphocyte trafficking and macrophage function, and (iii) the expected predictivity of non-human primate models for the occurrence of encephalic polyomavirus infections.