UPDATE 2-Roche's MabThera cuts arthritis joint damage

* Cut progression of joint damage as first line treatment

* Roche aims to expand use of cancer drug to other diseases

* Stock up 2.2 percent, also helped by positive study

(Adds detail on MabThera, comment, updates shares)

ZURICH, June 11 (Reuters) - Data showed Roche Holding AG's (ROG.VX) MabThera cancer drug reduced the progression of joint damage when used as a first line treatment for rheumatoid arthritis (RA), the Swiss group said on Thursday. Results of the so-called IMAGE study, presented at a European League Against Rheumatism meeting, showed a course of two infusions of MabThera given every 24 weeks can significantly slow damage after a year of treatment.

Roche stock had risen 2.2 percent to 146 Swiss francs by 1511 GMT, versus a 1.7 percent rise in the European health care sector .SXDP.

The stock was also helped by a positive sector study by analysts at Morgan Stanley. "It's really a mixture of both," a trader said. [ID:nBNG430876]

MabThera is currently approved for use in RA patients who do not respond to other drugs known as tumour necrosis factor inhibitors, and Roche hopes to expand its use further in autoimmune diseases.

MabThera is known as Rituxan in the United States, where it is marketed by Roche's recently acquired Genentech partner and Biogen Idec Inc (BIIB.O). It is the Swiss company's biggest seller. (Reporting by Sam Cage, editing by Will Waterman)