IQVIA supports DMARC compliance via SPF.
Contact IQVIA support to ask about their DKIM capabilities.
All traffic we've noticed comes from 'usadc-smtpamr.quintiles.com' which for the time being translates into an addition of 'ip4:192.69.83.25' to your SPF. Before making changes to your SPF however, contact IQVIA to verify this information.