UPDATE 1-Roche's Actemra helps in hard-to-treat arthritis

(Adds details from statement, background)

By Sam Cage

ZURICH, June 13 (Reuters) - Thirty percent of rheumatoid arthritis patients who failed to respond adequately to anti-TNF therapy achieved remission from their disease when given Roche's (ROG.VX) new drug Actemra, research showed on Friday.

After 24 weeks of treatment, 30.1 percent of patients receiving Actemra plus the older drug methotrexate achieved DAS28 -- a standard measure of disease remission -- compared with only 1.6 percent in the placebo group, the Swiss group said.

Roche says rheumatoid arthritis -- characterised by inflammation of the membrane lining joints throughout the body, which can cause pain, stiffness and swelling and ultimately disability -- is thought to affect 21 million people worldwide.

Actemra is an anti-interleukin-6 receptor antibody and works in a different way to the existing class of anti-TNF medicines that block an inflammatory protein called tumour necrosis factor.

"These study results are very promising for RA patients who need a variety of treatment options, particularly when they have failed to achieve adequate pain and symptom relief with anti-TNF therapies," lead investigator Paul Emery said in a statement.

The new drug, which Roche sees as a potential billion dollar seller, is approved in Japan -- where it is sold by Roche's partner Chugai Pharmaceutical Co Ltd (4519.T) -- but has yet to reach the market in Europe or the United States.

It will be considered for approval by a U.S. Food and Drug Administration panel on July 29.