mitochondria dysfunction ALS


Power up Biogen Idec's dexpramipexole hoped to slow ALS by keeping the power on in the deteriorating motor nerves. Image: Judith Stoffer, NIGMS.

Biogen Idec pulled the plug on its potential energy booster, dexpramipexole, this month due to its inability to show efficacy at the phase III stage in the clinic. 

The drug is one of two emerging medicines that appeared to slow ALS by more than 30% at phase II. And, one of at least 9 drugs at phase III that were unable to show substantial benefit in the clinic.

Nearly 1000 people with ALS participated in the phase III clinical trial.

The results suggest that experts might need to rethink the design of phase II clinical trials for ALS to better inform go/no go decisions.

ALS Today’s Michelle Pflumm PhD talked with Biogen Idec’s Director of Neurodegenerative Research Doug Kerr MD PhD about dexpramipexole, the lessons learned and the development of future medicines for ALS going forward.


To find out about other emerging treatment strategies for ALS, check out our 2012 International Symposium on ALS/MND meeting review ALS Trials and Tribulations.


Cudkowicz, M. et al. (2011) The effects of dexpramipexole (KNS-760704) in individuals with amyotrophic lateral sclerosis.  Nature Medicine. doi: 10.1038/nm 2579  Abstract Full Text (Subscription Required)

Gribkoff, V.K. and Bozik, M.E. (2008) KNS-760704 [(6R)-4,5,6,7-tetrahydro-N6-propyl-2,6-benzothiazole-diamine dihydrochloride monohydrate] for the Treatment of Amyotrophic Lateral Sclerosis CNS Neuroscience and Therapeutics 14, 215-226.  Abstract Full Text (Subscription Required)

Alavian K.N. et al. (2012) Effects of dexpramipexole on brain mitochondrial conductances and cellular bioenergetic efficiency. Brain Research 1446, 1-11. Abstract Full Text (Subscription Required)

Further Reading

Gladman, M., Cudkowicz, M. and Zinman, L. (2012) Enhancing clinical trials in neurodegenerative disorders: lessons from amyotrophic lateral sclerosis. Current Opinion in Neurology 25, 735-742. Abstract Full Text (Subscription Required)