A South Korean team conducted a randomised trial of 6′-sialyllactose (6SL) versus placebo in GNE myopathy for almost two years (96 weeks) in 20 participants aged between 24 and 58 years with an average disease duration of 8.6±5.1 years:
- seven participants received 3g/d of 6SL (low dose), seven others 6g/d (high dose) and six others placebo for three months before three of them received the low dose of 6SL and the other three the high dose.
- Free sialic acid levels were significantly increased at 12 weeks in participants taking 6SL, while levels of sialic acid bound to red blood cell membranes were significantly increased after three months only in the high-dose group.
- 6SL was well tolerated, with a few gastrointestinal side-effects (diarrhoea, constipation) and intermittent headaches during the first six weeks.
- Although muscle strength showed no difference between the three groups after 12 weeks, the strength of the proximal muscles of the high-dose participants tended to increase at 96 weeks, starting at 48 weeks for shoulder abduction and elbow flexion.
- a composite score for upper limb strength showed no significant improvement, while that for lower limb strength showed a trend towards improvement at both low and high doses, where it reached the threshold of significance.
- There was no decrease in the fat fraction of the middle thigh and calf on MRI during the first 12 weeks in any of the three groups of participants. Overall, the increase in fat fraction was stabilised by both the low and high dose of 6SL in the latter part of the study, except for the anterior compartment of the thigh.
The fact that the duration and severity of the disease were not taken into account in this pilot trial means that it is not possible to demonstrate a clear trend in the effect of 6SL. For this reason, a placebo-controlled trial is currently underway to confirm these encouraging results.
