Outside of direct interaction with admin UI, not possible today. We continue to expose more of the ISE configuration including policy elements via API so expect that to be the next likely method to derive this information, but not available today. SNMP does not expose application-level data today, but even then, I doubt SNMP to be the likely method to retrieve policy configuration details. Be sure to submit enhancement requests to your Cisco sales team with information on business requirement and impact.
/Craig
