Initial studies showed promise but it appears nothing was done after 2009.
http://www.overcomingmultiplesclerosis.org/News-And-Events/Whats-New-Out-There/Detail/Minocycline+likely+to+be+highly+effective+in+MS+despite+poor+study+design/
http://www.msrc.co.uk/index.cfm/fuseaction/show/pageid/2350
http://www.bio-medicine.org/medicine-technology/Treatment-with-Copaxone-Plus-Minocycline-Showed-Substantial-0AReduction-of-Disease-Activity-in-Patients-with-Active-0ARelapsing-Remitting-Multiple-Scl-787-5/