Anavex Life Sciences says its experimental Alzheimer's treatment met the goals of a midstage study, leading AVXL stock to rocket Friday.
On one measure of symptoms, Anavex said patients who received its pill, dubbed blarcamesine, showed a 45% slower rate of decline than the placebo group. But critics questioned the company's math, suggesting a subtraction issue could indicate the effectiveness was much lower.
Chief Executive Christopher Missling says their view of the data is incorrect.
"Statistics don't work like that for (effectiveness)," he told Investor's Business Daily. "We don't look at the average of all the patients at the beginning and the end. We look at each individual patient from beginning to end because that's what matters."
Even as today's stock market moved broadly lower, AVXL stock catapulted 35.9% to 12.05.
AVXL Stock: Clarifying Statistical Questions
Anavex tested blarcamesine in a 48-week study involving 509 patients with early Alzheimer's disease.
Researchers weighed the results of the treatment on a 70-point measure called the Alzheimer's Disease Assessment Scale-Cognition. Before receiving treatment, patients scored a 27.62. After treatment, blarcamesine scored a 30.36.
On average, the change over 48 weeks was 2.26 points, Anavex said in its presentation. This is where the company's critics say the average change should have been 2.74 points — subtracting the score at week 48 from the score before treatment. That change in subtraction would have led to a 33% effectiveness rate.
Missling says statistics don't work like that.
"The correct calculation is each individual patient," he said. "That is not in a simple end-of-trial minus baseline calculation that you can do on your calculator. It's a calculation of each individual patient."
Using the same scale of symptoms, Anavex said patients who received blarcamesine were 84% more likely to show improved cognition of at least half a point.
On a scale measuring activities of daily living, blarcamesine recipients were 167% more likely to have an improvement of at least 3.5 points than placebo recipients. The company didn't provide the specific number of patients that improved. Still, AVXL stock soared.
Anavex said the drug was generally safe and well tolerated. The most common side effect tied to the experimental Alzheimer's treatment was dizziness.
Shares Reverse A Downtrend
Anavex will publicly release additional data when available, Missling said.
"We literally received it on Wednesday," he said. "We had no chance to calculate more than this topline data and we are obliged for regulatory reasons to inform the public about the data because of its materiality."
Shares hit a 10-month high in November, but have since crumbled. AVXL stock reversed that downtrend on Friday after the company's late Thursday presentation.
"There's so much more data behind this (that) will come," Missling added. "We have no more information as of today."
Follow Allison Gatlin on Twitter at @IBD_AGatlin.
