Anavex stock sinks 30% as lead asset fails to improve Rett syndrome in children

Anavex stock sinks 30% as lead asset fails to improve Rett syndrome in children

Anavex Life Sciences’ lead asset has failed to significantly improve disease characteristics in a pediatric Rett syndrome trial, with the company pointing the blame toward a high placebo effect.

The New York City-based biotech’s stock cratered 30% since the data was shared earlier today, tumbling from $9.32 per share at market close Friday to $6.55 as of 10:30 a.m. ET.

The topline results come from a double-blind, placebo-controlled, phase 2/3 trial dubbed EXCELLENCE. The study evaluated daily 30 mg doses of ANAVEX 2-73—an orally available molecule also known as blarcamesine—in 92 pediatric patients with Rett syndrome (RTT), a rare non-inherited genetic neurodevelopmental disorder that occurs mostly in girls. There currently aren’t any disease-modifying therapies that tackle the genetic root cause of the condition on the market.

Sixty-two patients received the investigational treatment while 30 were randomized to the placebo arm. According to Anavex, the study’s co-primary endpoints were improvement as measured by two scales: a 45-item questionnaire filled out by the patients’ caregivers and an assessment completed by clinical site investigators using seven-point scoring, both conducted after 12 weeks. According to, the primary endpoints were improvement as measured by the 45-item scale and incidents of adverse events.

Anavex said that the therapy “showed improvement” on the 45-point scale, which was the key co-primary endpoint, and did not meet statistical significance on the other seven-point improvement scale.

In an ad-hoc analysis, mean differences between patients receiving the placebo versus ANAVEX 2-73 were not statistically significant for either scoring system at 12 weeks. Anavex also said that a secondary endpoint rating anxiety, depression and mood “trended favorably.”

Despite the failure, Anavex is still touting improvements in certain areas for Rett syndrome, like particular repetitive movements, nighttime disruptive behaviors and social avoidance. The company blamed placebo performance for the failure.

“Although data analysis is ongoing, the early conclusion is that the placebo rate could have been higher in the study due to a slight imbalance in disease severity at baseline, across the treatment arms, and the 2 to 1 drug to placebo randomization ratio,” Walter Kaufmann, M.D., Anavex’s chief scientific officer said in a Jan. 2 release. “We intend to further assess the collective results and discuss with the regulatory authorities next steps.”

A preliminary review of safety data found no new safety signals in the EXCELLENCE study, according to Avanex, which is also studying the therapy in adults with Rett syndrome, as well as in patients with Fragile X syndrome and Parkinson’s disease.

Most patients completing the trial have continued on to a 48-week open-label extension, which is ongoing. The FDA has tagged ANAVEX 2-73 with fast track designation, rare pediatric disease designation and orphan drug designation for treating Rett syndrome.

“Based on these study results, we will continue to be committed to the Rett syndrome and rare disease community, given also the prior successful two placebo-controlled studies in adult patients with Rett syndrome,” said Avanex CEO Christopher Missling, Ph.D.

The biotech came under fire in 2022 after touting a phase 3 win for adults with Rett syndrome after changing the study’s phase and main goals.

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