|There are many managed solutions available. E.g.:
1. Sophos End point security and control
2. TrendMicro OfficeScan
3. McAfee VirusScan Enterprise
However, the best solution depends on your needs!
Some variables could be:
1. Support/ SLA
3. Configuration/Management options
4. Integration with existing infrastructure
5. Confidentiality requirements (e.g. connecting to Vendor's servers is not acceptable)
See the following web-sites to get a feel of performance of various AV products.