The p2 5mg US Rett has much better efficiency than 30mg p3 international Rett. The odds ratio of p2 is over 7. The question here why p3 adult efficiency not nearly as good as p2, is the sample size too small, the 30mg not as effective as 5mg, or UK/Australian patients have different response profile?
The Adult p3 endpoint change is UK/Australia approved as confirmed in 10Q, but it also indicated the adult p3 endpoint changed did not go through FDA for approval.
Now the question is what’s p3 efficiency for international juvenile patients on a not disclosed dosage? The 3x p2 patients number and 2x longer trial duration should give us definitive answers.
Rett Syndrome
In March 2019, we commenced the first Phase 2 clinical trial in a planned Rett syndrome program of ANAVEX®2-73 for the treatment of Rett syndrome. The clinical trials are being conducted in a range of patient age demographics and geographic regions, utilizing an oral liquid once-daily formulation of ANAVEX®2-73.
The first Phase 2 trial, (ANAVEX®2-73-RS-001), which took place in the United States, was completed in December 2020. This trial was a randomized double-blind, placebo-controlled safety, tolerability, PK and efficacy trial of oral liquid ANAVEX®2-73 formulation in 25 adult female patients with Rett syndrome over a 7-week treatment period including ANAVEX®2-73-specific genomic precision medicine biomarkers. The primary endpoint of the trial was safety. The dosing of 5 mg ANAVEX®2-73 was well-tolerated and demonstrated dose-proportional PK. All secondary efficacy endpoints of the trial showed statistically significant and clinically meaningful response in the Rett Syndrome Behaviour Questionnaire (“RSBQ”) response, when compared to placebo, in the intent to treat (“ITT”) cohort (all participants, p = 0.011). 66.7% of ANAVEX®2-73 treated subjects showed a statistically significant improvement in RSBQ response as compared to 10% of the subjects on placebo in the ITT cohort (all participants, p = 0.011). ANAVEX®2-73 treatment resulted in a sustained improvement in Clinical Global Impression Improvement (CGI-I) response throughout the 7-week clinical trial, when compared to placebo in the ITT cohort (all participants, p = 0.014).
The second, international[color=red][/color] trial of ANAVEX®2-73 for the treatment of Rett syndrome, called the AVATAR trial, commenced in June 2019. This trial took place in Australia and the United Kingdom using a higher dose than the U.S. based Phase 2 trial for Rett syndrome. The trial was a Phase 3 randomized, double-blind, placebo-controlled trial to evaluate the safety and efficacy of ANAVEX®2-73 in 33 adult patients over a 7-week treatment period including ANAVEX®2-73 specific precision medicine biomarkers. Based upon the input from the successful U.S. Phase 2 Rett syndrome trial (ANAVEX®2-73-RS-001), we updated the endpoints for the AVATAR trial (ANAVEX®2-73-RS-002) to appropriately assess the clinically meaningful outcome following International Conference on Harmonization (ICH) guidelines. These updates were approved by the respective regulatory authorities in the U.K. and in Australia, respectively, where the AVATAR trial was conducted.
The data from the AVATAR trial was released in February 2022. The clinical trial met all primary and secondary efficacy and safety endpoints, with consistent improvements in primary efficacy endpoint, RSBQ response (p = 0.037), and secondary efficacy endpoints, ADAMS (p = 0.010) and CGI-I (p = 0.037) response. Efficacy endpoints demonstrated statistically significant and clinically meaningful reductions in Rett syndrome symptoms. Convenient once daily oral liquid doses of up to 30 mg of ANAVEX®2-73 were also well tolerated with good medication compliance. All patients who participated in the trial were eligible to receive ANAVEX®2-73 under a voluntary open label extension protocol.
In July 2020, we commenced the third trial of ANAVEX®2-73 for the treatment of Rett syndrome, called the EXCELLENCE trial. This Phase 2/3 trial in pediatric patients with Rett syndrome includes trial sites in Australia, the United Kingdom and Canada, and will evaluate the safety and efficacy of ANAVEX®2-73 in approximately 84 pediatric patients, aged 5 to 18, over a 12-week treatment period incorporating ANAVEX®2-73 specific precision medicine biomarkers. This trial completed enrollment in February 2023, exceeding the original enrollment target. In June 2023, this trial completed dosing of all participants, and topline results are expected in the second half of 2023. All patients who participate in the trial will be eligible to receive ANAVEX®2-73 under a voluntary open label extension protocol, which is currently ongoing.
