Anavex’s Stock Nosedives After Posting Trial Results for Rett Syndrome


Stock downtrend_iStock, lerbank

Pictured: Illustration showing a downward graph trend/iStock, lerbank

Anavex Life Sciences was hit with a stock selloff on Tuesday after it posted topline results from a Phase II/III study for its candidate ANAVEX2-73 in pediatric patients with Rett syndrome.

The study’s co-primary endpoint of the Clinical Global Impression-Improvement scale (CGI-I) was not reached, according to the results of the Excellence study after 12 weeks. CGI-I is an assessment scale determined by site investigators using a seven-point scale.

For the other primary endpoint, the Rett Syndrome Behavior Questionnaire (RSBQ), after 12 weeks the drug did not present statistical significance. The “improved LS Mean” in the candidate group was -12.93 points on the RSQ total score compared to -8.32 for those in the placebo group. A mean difference of -4.61 did not give statistical significance and had a p-value of p=0.0063.

However, it was not all negative results as patients in the ANAVEX2-73 group showed a “rapid onset of action” with improvements marked at four weeks after treatment with an RSBQ total score of -10.32 points compared to -5.67 points in the placebo group with a difference of -4.65 being statistically significant and earning a p-value of p=0.041.

Anavex also touted the secondary endpoint of the Anxiety, Depression, and Mood Scale as “trending favorably” but did not give any hard data.

However, the news was not enough for Wall Street, as the company saw a stock drop of over 35% on Tuesday.

“We believe that a high placebo response may have masked the therapeutic effect of this innovative orally available molecule. High placebo responses are well documented, especially in pediatric clinical studies. 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,” Anavex CSO Walter Kaufmann said in a statement. 

Kauffman added that the biotech plans to assess the results further and talk with regulatory authorities about its options going forward.

Anavex said that no new safety issues were identified in the study and despite the results, management is still keeping some positivity around the treatment.  

“We believe that ANAVEX2-73, as a new, potential convenient treatment option in the future, can contribute to patients and healthcare professionals by addressing unmet needs in the treatment of Rett syndrome,” Anavex CEO Christopher Missling, said in a statement.

Anavex is also investigating the candidate for other neurodevelopmental disorders, including Fragile X syndrome, as well as neurodegenerative disorders such as Parkinson’s disease. 

In September 2023, the company’s drug blarcamesine demonstrated that it could slow down the cognitive decline in patients with Alzheimer’s disease. In December 2023, its marketing authorization application for Alzheimer’s was approved by the European Medicines Agency.

Tyler Patchen is a staff writer at BioSpace. You can reach him at Follow him on LinkedIn.

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