The present invention provides a method for designing a re-targeted toxin conjugate for use in treating a medical condition or disease. Also provided, is the use of said conjugates in the manufacture of a medicament for treating medical conditions or diseases. The conjugates include a Targeting Moiety, which directs the conjugate to a desired target cell, and are characterised by a Targeting Moiety that increases exocytic fusion in the target cell. The present invention also provides methods for identifying agonists suitable for use as Targeting Moieties, and methods for preparing conjugates comprising said Targeting Moieties.