Dealing with uncertainties about cost effectiveness of treatments is difficult problem
BMJ 2003;326:1212-1213 (31 May)
David Chadwick , Richard Gray
 Walton Centre for Neurology and Neurosurgery, University of Liverpool, Liverpool L9 7LJ
 Birmingham Clinical Trials Unit, University of Birmingham, Birmingham B15 2TT
Letter to Editor
Sudlow and Counsell argue for a trial comparing disease modifying treatments with azathioprine, and placebo as an alternative to the risk sharing scheme, which they believe to be scientifically unsound.1 As independent scientific advisers to the scheme we would like to correct some inaccuracies.
Firstly, patients who have already been prescribed disease modifying treatments will not contribute to the main analyses of cost effectiveness.
Secondly, subjects will be followed up irrespective of compliance to allow intention to treat analyses.
Thirdly, there are no obviously better alternatives to the expanded disability status score. A quality assurance protocol is being developed, including further validation of the status score against cost utilities. Blinded assessments are unhelpful without a concurrent control group.
Fourthly, other series of patients with multiple sclerosis will be used to validate the Canadian historical control cohort.
Finally, the scheme has approval from the multicentre research ethics committee and includes resources for extra staff to collect data.
How best to deal with uncertainties about cost effectiveness of treatments is a difficult problem, particularly in chronic, disabling, neurological conditions where no other effective treatments exist. Industry sponsored licensing studies often leave important unanswered questions about clinical benefits. In retrospect, it is regrettable that the independent UK trial of cost effectiveness, proposed when the drugs were first licensed, was not funded and speedily implemented. Now that their use has become entrenched, denying patients the treatment until greater precision becomes available many years hence has become socially and politically unacceptable.
The scheme is a compromise to make the treatments available by sharing the financial burden with industry. Although it will not provide a reliable estimate of clinical effectiveness, it will deliver a high level of audit of outcome. Moreover, the risk sharing scheme should not be incompatible with Sudlow and Counsell's proposed trial. It may be too late, however, to include a placebo arm, as this is unlikely to be supported by clinicians or patients.
© 2003 BMJ Publishing Group Ltd