XenoPort to drop Arbaclofen for MS spasticity

“This study shows that even in late stage development (phase 3), with a drug that has more than a fighting chance, things can go wrong and you get a negative result. The http://www.clinicaltrials.gov trial entry (NCT01359566) suggest they did not use an enrichment design. Why? GW Pharma have shown so elegantly in their Sativex trials that this is the only way to do spasticity trials. In addition, the study used a co-primary outcome; i.e. (1) change from Baseline in maximum Ashworth scale score (6 hour post-dose time point) and (2) a Patient Global Impression of Change (PGIC) score. We now know that the Ashworth is not a good outcome measure; it is not responsive to change and unreliable. At first glance 228 MSers seems to be massively underpowered for these outcomes; there appears to have been 4 arms (placebo vs. 15mg vs. 30mg vs. 45mg) or 57 MSers per arm. For the Ashworth scale you need several hundred per group. I would be very keen to do a post-mortem of this study to see if we can learn something useful from this failure. I sincerely hope that this drug did not fail because of poor trial design.”

“Is this another story of a baby being thrown out with the bathwater?”

“You may be interested to know that Acorda’s trials of fampridine, also used an enrichment design. This means that only responders are entered into the double-blind placebo-controlled study. This design may seem counterintuitive, but it is what the Regulators now expect for symptomatic therapies.”

CoI: multiple

4 thoughts on “XenoPort to drop Arbaclofen for MS spasticity”

  1. It was baclofen just an extended release formulation the hope was that it should get you through the night. It is inconceivable that it could not work as well as baclofen…anyway less competition for our compound.coi:We are developing a drug for spasticity.

    1. Baclofen is an analgesic; however if it relieves spasms it may reduce pain.

Leave a Reply

%d bloggers like this: