To be precise. Agile Accelerator was a heavily customised QC Project developed by HP Professional Services in Version 10. Then it was ported to Version 11. It was/is available in two flavours - basic and extended. Basic was free and Extended which has the valuable features would by unlocked after parting with additional money.
Agile Manager is a purely SaaS solution and has been developed from scratch as such - although many of the features from the original QC Project have been adopted.