The condition attacks the joints
A monthly injection could halt rheumatoid arthritis (RA) in half of all patients, trial data suggests.
The antibody drug tocilizumab works in conjunction with an existing treatment, methotrexate, to stop the condition in which the body attacks its own joints.
The drug, which will be sold under the brand name RoActemra by Roche, is awaiting approval by drugs regulators in Europe and the US.
The work was presented at a meeting of the American College of Rheumatology.
Nothing can be done to reverse the damage caused by RA but the new results show the two drugs taken together can achieve remission by stopping progression of the disease.
In trials involving 1,190 patients, taking tocilizumab plus methotrexate halted the condition in 47% of patients, compared to only 8% when methotrexate was taken alone.
X-rays showed the combination treatment slowed structural damage to joints by 85% on average, compared with 67% for methotrexate alone.
Professor Paul Emery, from Leeds University, who led the study said: "Results of this pivotal study convincingly demonstrate that tocilizumab can effectively and rapidly diminish the painful and debilitating effects of RA.
"These trial findings are significant because it is critical to stop joint damage as quickly as possible to avoid joint deformity and to help people with RA maintain their quality of life."
There are other drugs available - anti-TNF therapy - that can halt RA disease progression.
In the UK, however, the use of these drugs on the NHS is restricted.
A spokeswoman for the Arthritis Research Campaign, whose scientists pioneered earlier anti-TNF therapy, said: "New trial data for tocilizumab is extremely encouraging and this drug could be an effective option for the 30% of people who fail on anti-TNF therapy.
"It's great news for people with rheumatoid arthritis as after years of having very few drugs available to them that slow down disease progression, there are suddenly several promising new therapies in the pipeline."
Ailsa Bosworth, chief executive of the National Rheumatoid Arthritis Society, said: "We are encouraged by these findings, particularly as the treatment shows such promise of achieving remission, the ultimate goal for people with this cruel and debilitating disease.
"These results present new hope for the hundreds of thousands of people who suffer from RA in the UK."
Professor Iain McInnes, from the University of Glasgow, said: "We have seen great advances with the advent of biologic therapies however, a significant proportion of patients achieve only a partial response or do not respond at all to our current therapies.
"Newer treatments are required that will not only effectively treat the signs and symptoms of RA, but also prevent joint damage and help patients achieve remission - the 'Holy Grail' when treating RA.
"Tocilizumab data suggests that we are moving in the right direction and this exciting new treatment promises to be a powerful weapon in the fight against RA."
There are 400,000 people in the UK with RA.