The multiple sclerosis study published in the journal The Lancet found that alemtuzumab significantly reduced the number of attacks or relapses by people with MS.
This result was seen both in patients who had not previously received any treatment and those who have continued to show disease activity while taking an existing treatment for MS.
In one trial with patients who had recently relapsed, new episodes were reduced by 49% more than that achieved by the current standard treatment.
Over a two-year period, 65% of patients on alemtuzumab compared with 47% of patients on interferon did not relapse.
More top news
Big companies will have to show that their supply chains do not use child slave labour or exploit people, David Cameron has announced.
Disneyland Paris is reportedly facing a pricing probe amid claims it charges British tourists more than its French customers.
Overworked GPs are becoming so tired they could be putting patient's safety at risk, the head of British general practitioners has warned.