Praxis stock tanks after mid-stage movement disorder trial miss

Praxis Precision Medicines has missed its goal in a Phase IIb trial after rolling out positive Phase IIa results last year.

The CNS-focused biotech announced Friday morning that the mid-stage trial did not reach statistical significance in the study’s primary endpoint. The Phase IIb trial, examining drug candidate PRAX-944 in patients with a condition called essential tremor, showed the drug induced an average 3.01-point reduction from baseline in a daily living activity score, compared to a 1.44-point reduction from placebo after eight weeks.

However, Praxis said the p-value was p=0.126, missing the statistical significance threshold.

Shares of the biotech $PRAX fell 60% after the market opened Friday morning to under $1.20 a share.

Marcio Souza

CEO Marcio Souza said Friday morning on a conference call that “we plan to meet with the FDA shortly in an end of Phase II meeting and advance the program to Phase III by the end of this year.”

The chief executive pointed out the trial used a modified activities of daily living (mADL) score, which included two performance scale items: spiral drawing (left and right) and handwriting, emphasizing that performance in those two items played a role in the final results.

Souza told Endpoints News after the conference call that the FDA had Praxis modify the original ADL scoring system, which had a maximum score of 48 — a rating of 0-4 on 12 different variables. The modified version, which changed the rating range to 0-3, removed the social impact score and replaced it with the drawing and handwriting. The new maximum score was 42.

A post-hoc analysis revealed that when the performance items were removed, efficacy could still be demonstrated with a p-value of p=0.042. Another post-hoc analysis — using the original ADL scoring system — also showed an improvement with a p-value of p=0.026.

Souza added he would take the “safe approach” and use the FDA’s recommendation in moving the drug forward.

The biotech first came on the scene in 2020, emerging out of stealth with $100 million in backing from Novo Holdings, Vida Ventures and Eventide, among others. Praxis reported positive Phase IIa data back in May, showing a 42% improvement from baseline using a modified ADL score in a smaller trial.

The randomized, placebo-controlled trial enrolled 132 patients to study the T-type calcium channel blocker candidate in patients with essential tremor, a relatively common neurological disorder that causes involuntary and rhythmic shaking. While the cause is unknown, it’s estimated to affect millions of people in the United States.

Essential tremor does not have a specifically designed approved treatment. Previous attempts have not succeeded in the past, as Neurocrine stopped development of its program last year after failing a Phase II study with 30 patients. That drug candidate is still being tested in epilepsy.

fda
shares
biotech