Yes SDD 4.1 does have API support.
To start using the SAS Drug Development Java API, you must first establish a session with your instance of the application. From the session, you can obtain the services that are currently delivered which provide a number of methods for resource manipulation. For example:
See RepositoryResourceService and WorkspaceResourceService for a list of methods currently available in the API.
There is also a samples directory which includes instructions on how you can set up an environment to use the API as well as providing several full example programs that illustrate the use of the API.