ZURICH - Swiss drugmaker Roche Holding AG said on Monday new two-year data showed the effectiveness of its Actemra drug in inhibiting structural damage to the joints of patient with rheumatoid arthritis.

Roche, the world's largest maker of cancer drugs, said the data also showed use of the drug improved patients' ability to perform everyday activities and helped maintain high remission rates.

Roche said X-rays of bone erosions and a narrowing of joint spaces showed that more patients treated with Actemra in combination with the current standard therapy, methotrexate, saw a significant inhibition of structural damage during 24 months of treatment when compared to patients in a control group.

The company said full data from the trial would be used to support regulatory filings for labelling claims.

Actemra is one of Roche's big hopes for future sales growth. The drug has already been launched in Japan and Europe. (Reporting by Martin de Sa'Pinto; editing by Mike Nesbit)