The phrase "to develop the agent" is an idiomatic expression that means to train, educate or improve someone's skills so they can perform a particular task more effectively. Full definition
The Breakthrough Therapy designation was granted based on interim results of a phase I trial, which the companies developing the agent have not yet released. (cancernetwork.com)
Hence, there is considerable interest in developing agents capable of inhibiting myostatin activity for both agricultural and human therapeutic applications. (journals.plos.org)
We could essentially develop agents that put a spanner in the works, stopping the factory production of TNF.» (sciencedaily.com)