ADHD Candidate Drug Abandoned Following Phase 3 Failure

After spotty trials, Alcobra's MDX met its end as a potential ADHD treatment.

Alcobra’s Metadoxine Extended Release, or MDX, will no longer be tested after disappointing results in a phase 3 trial, the company reported today. The drug was intended as a treatment for attention deficit/hyperactivity disorder (ADHD) and Fragile X Syndrome.

The primary endpoint for the MEASURE study, as it was called, was improvement over baseline in the Conners’ Adult ADHD Rating Scales (CAARS). In the trial, MDX did not achieve any statistically significant gains over placebo.

Yaron Daniely, PhD, CEO of the small Israeli drug maker, described the company as “extremely disappointed” with the top-line results. In September of 2016, the US Food and Drug Administration (FDA) placed a full clinical hold on the trials, citing what they called “adverse neurological findings,” though early phase trials seemed to indicate difficulty proving efficacy as opposed to major negative side effects.

The drug has yet to shine in tests of its other studied application, as a treatment for Fragile X syndrome, a genetic condition responsible for mental disabilities. Despite announcing that its results were not statistically significant for primary endpoints in a phase 2 trial in June of 2015, the FDA granted it a fast-track designation for that condition that September. Still after today’s news, however, it’s speculated that Alcobra will continue to explore the application of MDX in Fragile X and other conditions.

The cancellation of testing for ADHD applications comes a week after the company negotiated with the FDA to reduce the constraints of the clinical hold, and had proposed to conduct a six-month phase 1 animal trial to assess MDX's safety. The FDA was considering that offer.

Metadoxine, MDX’s active ingredient, has shown efficacy in the treatment of acute alcohol intoxication and management of alcoholism.

The disappointing phase 3 results were announced earlier today in a press release, and the company’s plans to move on from testing the drug for ADHD were confirmed later in a conference call, as reported by Reuters. The immediate aftermath has devastated Alcobra’s stock value.

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