Biologic drugs for analgesia: redefining the opportunity.

Chronic pain conditions present a huge burden on modern society. Both inflammatory and neuropathic pain are poorly treated in man; the majority of patients do not benefit from adequate pain relief, and side effects of currently used treatments are common. Discovery and development of novel therapies remains an imperative, but the ability to genuinely test the efficacy of novel therapies is often limited by effects at targets other than intended, particularly with novel small molecule approaches. Approaches which limit these off-target activities, and thus avoid the commonest cause of terminating development of new therapeutics may provide a greater ability to genuinely test targets of choice clinically, and here, biologic therapeutics provide such an opportunity; in the major class of biologic therapies, monoclonal antibodies, inherent exquisite selectivity is intrinsic to their nature. Antibody therapeutics have been developed successfully in the immunology and cancer fields, and recent progress in analgesia suggests that these therapeutics may transform treatment paradigms in a similar manner to that observed within, for example, the rheumatoid arthritis space. In addition, opportunities with other biologic approaches, such as peptides, further broadens the potential to bring forward genuinely novel approaches to pain. In this review, the current status of biologic therapies, as well as future opportunities are reviewed.