Praxis Precision Medicines Announces Alignment with FDA on Simplified and Accelerated Registrational Pathway for Elsunersen in Early Onset SCN2A Developmental and Epileptic Encephalopathy

Rhea-AI Summary

Praxis Precision Medicines (NASDAQ: PRAX) announced FDA alignment to convert the EMBRAVE3 registrational study of elsunersen in early-onset SCN2A developmental and epileptic encephalopathy to a single-arm, baseline-controlled design.

Key changes: enrollment target reduced to 30 patients from 40, all screening patients will receive elsunersen for 24 weeks then enter an open-label extension, and the primary endpoint is change from baseline in countable motor seizures. Enrollment is accelerating and topline results are expected in 2026; EMBRAVE Part A (n=9) topline readout is expected in 1H 2026.

Positive

• FDA agreed to convert EMBRAVE3 to single-arm registrational design
• All screening patients will receive elsunersen from day one
• Enrollment accelerating with topline results expected in 2026
• EMBRAVE Part A enrolled 9 patients with readout expected 1H 2026

Negative

• EMBRAVE3 sample size reduced from 40 to 30 patients
• Study converted from randomized sham-controlled to single-arm design
• Primary analysis limited to change from baseline in motor seizures

News Market Reaction – PRAX

-4.74%

2 alerts

-4.74% News Effect

-$321M Valuation Impact

$6.46B Market Cap

0.6x Rel. Volume

On the day this news was published, PRAX declined 4.74%, reflecting a moderate negative market reaction. Our momentum scanner triggered 2 alerts that day, indicating moderate trading interest and price volatility. This price movement removed approximately $321M from the company's valuation, bringing the market cap to $6.46B at that time.

Data tracked by StockTitan Argus on the day of publication.

Key Figures

EMBRAVE Part A sample size: n=9 patients EMBRAVE3 target enrollment: 30 patients Original EMBRAVE3 enrollment: 40 patients +5 more

8 metrics

EMBRAVE Part A sample size n=9 patients Ongoing EMBRAVE Part A trial topline expected 1H 2026

EMBRAVE3 target enrollment 30 patients Single-arm, baseline-controlled EMBRAVE3 registrational study

Original EMBRAVE3 enrollment 40 patients Prior double-blind, sham-controlled EMBRAVE3 design

EMBRAVE3 treatment duration 24 weeks All patients receive elsunersen before open-label extension

EMBRAVE Part A duration 20 weeks Randomized 3:1 elsunersen vs placebo/sham before extension

Cash & securities $389.2 million As of September 30, 2025 (Q3 2025 10-Q)

Net proceeds offering $567.0 million October 2025 public equity and pre-funded warrant offering

Q3 2025 net loss $73.9 million Quarter ended September 30, 2025

Market Reality Check

Price: $342.46 Vol: Volume 1,547,716 vs 20-da...

normal vol

$342.46 Last Close

Volume Volume 1,547,716 vs 20-day average 1,095,559 (relative volume 1.41). normal

Technical Price 270.98 is above 200-day MA of 70.33 and 2.53% below 52-week high 278.

Peers on Argus

PRAX rose 9.27% while key biotech peers (e.g., SANA -13.78%, AVXL -3.12%, ZBIO -...

PRAX rose 9.27% while key biotech peers (e.g., SANA -13.78%, AVXL -3.12%, ZBIO -2.03%) were broadly negative, indicating a stock-specific reaction rather than a sector-wide move.

Historical Context

5 past events · Latest: Dec 04 (Positive)

Pattern 5 events

Date	Event	Sentiment	Move	Catalyst
Dec 04	Clinical results	Positive	+3.0%	Positive registrational EMBOLD results with early stop for efficacy in DEEs.
Dec 04	Regulatory update	Positive	+3.0%	Positive pre-NDA FDA meeting for ulixacaltamide in essential tremor.
Dec 03	Equity compensation	Neutral	+3.9%	Inducement RSU grants to new employees under 2024 Inducement Plan.
Nov 24	Conference presentations	Neutral	-3.5%	Planned AES meeting presentations across epilepsy portfolio programs.
Nov 20	Investor event	Neutral	-13.3%	Announcement of an analyst-hosted fireside chat on ulixacaltamide data.

Pattern Detected

Recent company news has often coincided with positive price reactions, especially around clinical and regulatory milestones, though there are instances of divergence on event-related communications.

Recent Company History

Over the last few weeks, Praxis has reported multiple epilepsy and movement-disorder milestones. On Nov 20–24, it highlighted an expert fireside chat and upcoming American Epilepsy Society presentations, which saw mixed price reactions. In early December, PRAX announced positive EMBOLD results in SCN2A/SCN8A DEEs and a positive pre-NDA meeting for ulixacaltamide, both followed by +3.05% moves. Today’s FDA alignment on a simplified registrational pathway for elsunersen extends this trend of advancing late-stage CNS programs.

Market Pulse Summary

This announcement details FDA alignment on converting EMBRAVE3 into a single-arm, baseline-controlle...

Analysis

This announcement details FDA alignment on converting EMBRAVE3 into a single-arm, baseline-controlled registrational study for elsunersen in early-onset SCN2A-DEE, with all patients receiving treatment for 24 weeks and topline data expected in 2026. It complements ongoing EMBRAVE Part A work and follows recent positive updates in ulixacaltamide and relutrigine. Investors may track future readouts, regulatory interactions, and how Praxis deploys its Q3 cash balance of $389.2 million against its late-stage pipeline.

Key Terms

single-arm study, baseline-controlled study, double-blind, sham-controlled, +3 more

7 terms

single-arm study medical

"convert the EMBRAVE3 registrational study ... into a single-arm study where all patients"

A single-arm study tests a treatment in one group of participants without comparing it to a placebo or another therapy; think of trying a new recipe and noting results without cooking a different version side-by-side. For investors, such studies can show whether a treatment has promising effects and help speed development, but they carry more uncertainty than comparative trials because improvements might reflect chance, patient selection, or other factors rather than the treatment itself.

baseline-controlled study medical

"converted from a double-blind, sham-controlled study to a single-arm, baseline-controlled study"

A baseline-controlled study measures each participant before a treatment and then compares their later results to their own starting point, so people act as their own control. For investors, this design can reveal whether a product or therapy produces a measurable change within individuals — like checking weight before and after a diet — but it can be less convincing than comparisons against separate, randomized control groups when judging real-world effectiveness.

double-blind medical

"converted from a double-blind, sham-controlled study to a single-arm"

A double-blind process means that neither the people conducting an activity nor the people involved know certain key details, such as who is receiving a treatment or a placebo. This approach helps prevent bias from influencing the results, making the outcome more trustworthy. For investors, it ensures that decisions or judgments are based on unbiased information rather than preconceived opinions or expectations.

sham-controlled medical

"converted from a double-blind, sham-controlled study to a single-arm"

A sham-controlled trial compares a real medical procedure or device to a fake version that looks and feels the same but has no therapeutic effect, much like a sugar pill for surgery or implants. For investors, sham control is a sign of rigorous testing because it helps separate true treatment benefits from placebo effects or patient expectations, making clinical results and regulatory prospects more reliable when assessing commercial potential.

open-label extension medical

"24 weeks, followed by an open-label extension"

An open-label extension is a continuation of a clinical trial where all participants and researchers know which treatment is being given, often after an initial blinded phase. It allows further study of a drug's long-term safety and effectiveness. For investors, it can indicate ongoing interest and confidence in a product's potential, influencing perceptions of its future value.

developmental and epileptic encephalopathy medical

"elsunersen in early-onset SCN2A developmental and epileptic encephalopathy (DEE)"

A severe neurological condition that begins in infancy or early childhood, marked by frequent, hard-to-control seizures and slowing or loss of normal development such as movement, learning and communication. Think of it as a critical control system in a child’s brain that malfunctions and interferes with growth and daily function. For investors it signals a high unmet medical need, focused regulatory attention and the potential for significant commercial value — but also greater clinical and development risk for therapies.

gain-of-function medical

"bring the first targeted therapy for SCN2A gain-of-function disease to patients"

A laboratory change that makes a virus, bacterium or other biological agent more capable — for example more transmissible, more stable, or better at infecting cells. Like upgrading a tool to make it stronger or faster, such changes can speed scientific progress but also raise safety and ethical concerns; for investors this matters because heightened regulatory scrutiny, trial delays, insurance and reputational risk can affect funding, approvals and a company’s stock value.

AI-generated analysis. Not financial advice.

Clear recognition of high unmet need and urgency for the SCN2A community and plausibility of the mechanism of elsunersen 

FDA agreed to proposed changes to the EMBRAVE3 trial design to be a single-arm, baseline-controlled study

Enrollment in EMBRAVE3 is quickly accelerating and topline results expected in 2026

Topline results from ongoing EMBRAVE study (Part A, n=9) expected in 1H 2026

BOSTON, Dec. 09, 2025 (GLOBE NEWSWIRE) -- Praxis Precision Medicines, Inc. (NASDAQ: PRAX), a clinical-stage biopharmaceutical company translating genetic insights into the development of therapies for central nervous system (CNS) disorders characterized by neuronal excitation-inhibition imbalance, today announced the completion of a Type C meeting with the U.S. Food and Drug Administration (FDA) and agreement to immediately convert the EMBRAVE3 registrational study of elsunersen in early-onset SCN2A developmental and epileptic encephalopathy (DEE) into a single-arm study where all patients will receive elsunersen for 24 weeks, followed by an open-label extension.

Key Changes to EMBRAVE3

• The current study has been immediately converted from a double-blind, sham-controlled study to a single-arm, baseline-controlled study, enrolling 30 patients reduced from 40 patients.
• All patients currently in screening will be assigned to receive elsunersen.
• The primary analysis will be the change from baseline in countable motor seizures.
  
  

Update on EMBRAVE Study status

• The EMBRAVE Study Part A enrolled 9 patients randomized 3:1 to elsunersen or placebo/sham for 20 weeks, followed by a blinded transition to elsunersen for up to 2 years in an open-label extension.
• Praxis expects to complete Part A and disclose the topline results in the first half of 2026.
  
  

“This alignment with the FDA represents a meaningful step forward for patients and families living with SCN2A-DEE. The Agency’s recognition of both the urgency of the unmet need and the strong mechanistic rationale for elsunersen enables us to move with greater clarity and speed. Converting EMBRAVE3 to a single-arm, baseline-controlled study ensures that every child entering the trial will receive active treatment from day one, while preserving a rigorous and approvable pathway. Momentum in enrollment continues to build, and we remain focused on generating the evidence needed to bring the first targeted therapy for SCN2A gain-of-function disease to patients as quickly as possible,” said Marcio Souza, president and chief executive officer.

About Elsunersen (PRAX-222)
Elsunersen is an antisense oligonucleotide (ASO) designed to selectively decrease SCN2A gene expression, directly targeting the underlying cause of early-seizure-onset SCN2A developmental and epileptic encephalopathy (DEE) to treat seizures and other symptoms in patients with gain-of-function SCN2A mutations. In vitro studies of elsunersen have demonstrated reduction in both SCN2A gene expression and protein levels. In vivo, elsunersen has demonstrated significant, dose-dependent reduction in seizures, improvement in behavioral and locomotor activity and increased survival in SCN2A mouse models, with potential to be the first disease-modifying treatment for SCN2A-DEE. Elsunersen has received Orphan Drug Designation (ODD) and Rare Pediatric Disease Designation (RPDD) from the FDA, and ODD and PRIME designations from the European Medicines Agency for the treatment of SCN2A-DEE. To learn more about the EMBRAVE3 study, please visit https://www.embravestudy.com/.

About Praxis  

Praxis Precision Medicines is a clinical-stage biopharmaceutical company translating insights from genetic epilepsies into the development of therapies for CNS disorders characterized by neuronal excitation-inhibition imbalance. Praxis is applying genetic insights to the discovery and development of therapies for rare and more prevalent neurological disorders through our proprietary small molecule platform, Cerebrum™, and antisense oligonucleotide (ASO) platform, Solidus™, using our understanding of shared biological targets and circuits in the brain. Praxis has established a diversified, multimodal CNS portfolio including multiple programs across movement disorders and epilepsy, with four clinical-stage product candidates. For more information, please visit www.praxismedicines.com and follow us on Facebook, Instagram, LinkedIn and Twitter/X.

Forward-Looking Statements 
This press release contains forward-looking statements within the meaning of The Private Securities Litigation Reform Act of 1995 and other federal securities laws, including express or implied statements regarding Praxis’ future expectations, plans and prospects, including, without limitation, statements regarding the anticipated timing of clinical trials and the development of Praxis’ product candidates, as well as other statements containing the words “anticipate,” “believe,” “continue,” “could,” “endeavor,” “estimate,” “expect,” “anticipate,” “intend,” “may,” “might,” “plan,” “potential,” “predict,” “project,” “seek,” “should,” “target,” “will” or “would” and similar expressions that constitute forward-looking statements under the Private Securities Litigation Reform Act of 1995.

The express or implied forward-looking statements included in this press release are only predictions and are subject to a number of risks, uncertainties and assumptions, including, without limitation: uncertainties inherent in clinical trials; the expected timing of clinical trials, data readouts and the results thereof, and submissions for regulatory approval or review by governmental authorities; regulatory approvals to conduct trials; and other risks concerning Praxis’ programs and operations as described in its Annual Report on Form 10-K for the year ended December 31, 2024 and as updated in its Quarterly Report on Form 10-Q for the quarter ended June 30, 2025, as well as other filings made with the Securities and Exchange Commission. Although Praxis’ forward-looking statements reflect the good faith judgment of its management, these statements are based only on information and factors currently known by Praxis. As a result, you are cautioned not to rely on these forward-looking statements. Any forward-looking statement made in this press release speaks only as of the date on which it is made. Praxis undertakes no obligation to publicly update or revise any forward-looking statement, whether as a result of new information, future developments or otherwise.

Investor Contact:
Praxis Precision Medicines
investors@praxismedicines.com
857-702-9452  

Media Contact:
Dan Ferry
Life Science Advisors
Daniel@lifesciadvisors.com
617-430-7576

FAQ

What did Praxis announce about the EMBRAVE3 trial for PRAX on December 9, 2025?

Praxis announced FDA alignment to convert EMBRAVE3 to a single-arm, baseline-controlled registrational study and reduce enrollment to 30 patients.

How long will patients receive elsunersen in the EMBRAVE3 study (PRAX)?

All patients will receive elsunersen for 24 weeks, followed by an open-label extension.

When does Praxis expect topline results for EMBRAVE and EMBRAVE3 (PRAX)?

Praxis expects topline results in 2026; EMBRAVE Part A topline is expected in 1H 2026.

What is the primary endpoint for the converted EMBRAVE3 study (PRAX)?

The primary analysis will be the change from baseline in countable motor seizures.

How many patients were in EMBRAVE Part A and what was its design (PRAX)?

EMBRAVE Part A enrolled 9 patients, randomized 3:1 to elsunersen or placebo/sham for 20 weeks, then blinded transition to open-label elsunersen.