[Current outlook on botulinum toxin medications]

Botulinum toxin (BT) has been used therapeutically for more than 20 years. What is the outlook on further BT drug development? Strategies to avoid BT antibody formation substantially limit the potential of BT therapy. The development of low-antigenicity BT drugs therefore is of primary importance. This can be achieved by increasing the specific biological activity, thus reducing the botulinum neurotoxin protein load. It may also be done by separation of complexing proteins. However the development of high-affinity BT drugs may be the most promising approach. Other developmental aspects include transdermal BT application, BT labelling for improved application, ready-made BT solutions, and improved handling features. Although some of these aspects have been addressed in drugs recently entering the market, the ideal BT drug is still a long way ahead.