Stock Plunge for Anavex Following Rett Syndrome Trial Outcome

Anavex Life Sciences experienced a significant stock market decline following the release of its Phase II/III trial results for the drug ANAVEX2-73, which is intended for the treatment of pediatric Rett syndrome patients. The study did not meet its co-primary endpoint, the Clinical Global Impression-Improvement scale (CGI-I), after a 12-week period. This scale is a seven-point assessment made by site investigators.

Additionally, the Rett Syndrome Behavior Questionnaire (RSBQ), another primary endpoint, showed no statistical significance after the same duration. The candidate group's "improved LS Mean" was -12.93 points on the RSQ total score, contrasting with -8.32 points for the placebo group, resulting in a non-significant mean difference of -4.61 with a p-value of p=0.0063.

Despite these findings, there was a positive aspect: patients who received ANAVEX2-73 demonstrated a "rapid onset of action," with noticeable improvements at the four-week mark. The RSBQ total score for this group was -10.32 points, compared to -5.67 points for the placebo group, with a significant difference of -4.65 and a p-value of p=0.041.

Anavex highlighted the secondary endpoint of the Anxiety, Depression, and Mood Scale as showing favorable trends, although no concrete data was provided. Nevertheless, the financial markets reacted negatively to the news, with the company's stock value plummeting by over 35%.

Anavex's Chief Scientific Officer, Walter Kaufmann, suggested that a high placebo response might have obscured the therapeutic effects of ANAVEX2-73. He noted that high placebo responses are common in pediatric clinical studies and proposed that the study's placebo rate might have been elevated due to several factors, including a slight imbalance in disease severity at the outset and the 2 to 1 drug to placebo randomization ratio.

Kaufmann also indicated that Anavex intends to conduct a more thorough analysis of the results and consult with regulatory bodies to determine future steps. The company reported no new safety concerns arising from the study and maintained a positive outlook on the treatment's potential.

Anavex's CEO, Christopher Missling, expressed belief in ANAVEX2-73's future as a new and convenient treatment option that could address unmet needs in Rett syndrome treatment. The company is also exploring the drug's efficacy in other neurodevelopmental and neurodegenerative disorders, such as Fragile X syndrome and Parkinson’s disease.

In other developments, Anavex's drug blarcamesine showed promise in slowing cognitive decline in Alzheimer’s patients in September 2023, and in December 2023, it received marketing authorization from the European Medicines Agency for Alzheimer’s treatment.