The first pill to treat MS has been rejected by the National Institute for Health and Clinical Excellence (NICE).
NICE rejected the drug Gilenya (fingolimod) over 'uncertainties' about its effectiveness, saying there was not enough data and concerns over cost.
Campaigners, however, have urged the watchdog to reassess the draft guidance which is subject to consultation.
The drug has been developed to help adults with relapsing-remitting MS who suffer at least one relapse a year despite taking beta interferon drugs.
The MS Society called on NICE to work with the drug's manufacturers Norvartis so that the decision may be overturned.
Simon Gillespie, Chief Executive of the charity, urged the two to reconsider and re-evaluate the move.
However Professor Carole Longson, Director of the health technology evaluation centre at NICE, said its committee was not given enough evidence to show that the drug could reduce relapses any better than current treatments.