OBJECTIVES: The effect of interferon-beta1a (INF-beta1a; Rebif) was
studied in patients with chronic motor neuropathies not improving after
conventional treatments such as immunoglobulins, steroids,
cyclophosphamide or plasma exchange. METHODS: A prospective open study was
performed with a duration of 6-12 months. Three patients with a multifocal
motor neuropathy and one patient with a pure motor form of chronic
inflammatory demyelinating polyneuropathy were enrolled. Three patients
had anti-GM1 antibodies. Treatment consisted of subcutaneous injections of
IBF-beta1a (6 MIU), three times a week. Primary outcome was assessed at
the level of disability using the nine hole peg test, the 10 metres
walking test, and the modified Rankin scale. Secondary outcome was
measured at the impairment level using a slightly modified MRC sumscore.
RESULTS: All patients showed a significant improvement on the modified MRC
sumscore. The time required to walk 10 metres and to fulfil the nine hole
peg test was also significantly reduced in the first 3 months in most
patients. However, the translation of these results to functional
improvement on the modified Rankin was only seen in two patients. There
were no severe adverse events. Motor conduction blocks were partially
restored in one patient only. Anti-GM1 antibody titres did not change.
CONCLUSION: These findings indicate that severely affected patients with
chronic motor neuropathies not responding to conventional therapies may
improve when treated with INF-beta1a. From this study it is suggested that
INF-beta1a should be administered in patients with chronic motor
neuropathies for a period of up to 3 months before deciding to cease
treatment. A controlled trial is necessary to confirm these findings