Praxis Precision Medicines Highlights DEE Clinical Program Updates at Virtual Investor Event

Rhea-AI Summary

Praxis Precision Medicines (NASDAQ: PRAX) hosted a virtual investor event highlighting updates on their developmental and epileptic encephalopathies (DEEs) clinical programs. Key highlights include:

Their lead drug relutrigine showed promising results in the EMBOLD study, with patients achieving ~90% seizure reduction and extending seizure-free periods from 3 to 67 days after 11 months. The company plans to initiate the EMERALD registrational study in mid-2025, targeting a US market potential of $3+ billion.

For elsunersen, the EMBRAVE3 registrational trial will begin mid-2025, initially enrolling patients ages 2-18 with plans to extend to newborns. The global market potential is estimated at $1 billion with 5,000 addressable patients.

In their pipeline, Praxis expects to nominate development candidates for PRAX-100 (targeting monogenetic autism) by mid-2025, and PRAX-080 and PRAX-090 by end of 2025.

Positive

• EMBOLD study showed 90% mean seizure reduction from baseline in patients
• Mean seizure-free period increased from 3 to 67 days after 11 months of treatment
• Large market opportunity with $3+ billion US potential for relutrigine
• Strong enrollment in clinical trials with multiple catalysts expected through 2026
• Positive pre-clinical results across 10 different DEE disease models

Negative

• Topline results for key trials not expected until first half of 2026
• Limited patient population for elsunersen with only 5,000 globally addressable patients

Insights

Neurology Drug Development Expert

Praxis shows impressive 90% seizure reduction with relutrigine and advances multiple DEE programs with significant market potential and innovative trial designs.

The updated EMBOLD study data for relutrigine demonstrates remarkable efficacy with approximately 90% mean seizure reduction from baseline in patients with SCN2A and SCN8A developmental epileptic encephalopathies (DEEs). More impressively, the mean longest seizure-free period increased from just 3 days at baseline to 67 days after 11 months of treatment. Though based on a limited sample of 12 patients in the open-label extension, these results suggest potentially transformative benefits.

The preclinical data spanning 10 different DEE models provides robust mechanistic evidence supporting relutrigine's broader application beyond specific genetic subtypes. This scientifically justifies the upcoming EMERALD study targeting a wider DEE population of 160 patients based on clinical phenotype rather than genetic etiology.

The EMBRAVE3 trial design for elsunersen represents a significant innovation in ASO development. By potentially enabling treatment from birth, it aligns with the natural history of SCN2A gain-of-function DEE, which often manifests within the first three weeks of life. This early intervention approach could establish a new treatment paradigm where addressing the genetic defect before symptom accumulation might fundamentally alter disease trajectory.

The expanding ASO pipeline demonstrates Praxis's commitment to precision medicine in neurological disorders. The PRAX-100 program for SCN2A loss-of-function mutations addresses the underlying pathophysiology by significantly increasing protein levels, which could correct the fundamental defect in this form of monogenetic autism.

Biotech Financial Analyst

Praxis's dual-platform strategy targets both broad DEEs ($3B US market) and specific genetic subtypes, with multiple near-term catalysts driving potential value creation.

Praxis presents a comprehensive clinical development strategy that creates multiple potential revenue streams by targeting both broad DEE populations and specific genetic subtypes. The company estimates a substantial $3 billion US market opportunity for relutrigine based on 200,000+ patients and precedent pricing from other approved DEE therapies. The elsunersen program targeting SCN2A gain-of-function mutations addresses a smaller population (5,000 patients globally) but still represents a $1 billion market opportunity, reflecting the premium pricing potential for precision genetic medicines.

The company's dual platform approach—developing both small molecule sodium channel modulators and antisense oligonucleotides—provides scientific diversification while creating potential combination therapy opportunities, as explicitly noted for relutrigine with their ASO programs. This strategy positions Praxis to become a dominant player in the DEE therapeutic landscape.

With multiple programs advancing toward registrational trials and development candidate nominations expected throughout 2025, Praxis has established a regular cadence of potential value-creating catalysts. The strong enrollment in ongoing studies suggests solid operational execution capabilities.

The timeline visibility is excellent, with topline results for key programs expected in 2026, providing a clear horizon for data-driven valuation inflection points. The company's expansion into monogenetic autism with PRAX-100 strategically leverages their neurological disorder expertise while diversifying beyond pure epilepsy indications.

BOSTON, May 05, 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, hosted a virtual investor event on its clinical programs in developmental and epileptic encephalopathies (DEEs) on Friday, May 2, 2025.

“We were excited to highlight the significant opportunity in DEEs and progress Praxis is making in this field,” said Marcio Souza, president and chief executive officer of Praxis. “Relutrigine continues to show tremendous promise to broadly address the DEE market opportunity, supported by robust pre-clinical results in multiple DEE models and further strengthened by new data from the EMBOLD study showing increasing seizure control over time. We also presented the EMBRAVE3 design for elsunersen in SCN2A gain-of-function (GoF) patients. This is not only the shortest known trial for an antisense oligonucleotide (ASO) but also supports a potential regulatory pathway for early intervention with treatment starting at birth when symptoms of this devastating disease first appear. We are also thrilled to see great progress in our ASO portfolio, with PRAX-100 in mono-genetic autism on track to declare a development candidate by mid-year. This is truly an exciting period for the DEE community and Praxis, and we look forward to continue sharing our progress with multiple upcoming catalysts.”

The slide presentation and a replay of the event are available on Praxis’ website on the “Events and Presentations” page under the investor section.

Key Event Topics and Highlights:

Relutrigine

• Praxis shared updated data from the initial cohort of patients in the EMBOLD study, highlighting results through 11 months of patient dosing. The open-label extension (OLE) includes 12 patients who continued on relutrigine following completion of the initial four-month double-blind period:
  • Patients achieved a mean seizure reduction of approximately 90% from baseline.
  • The mean longest period without seizures for patients is 67 days after 11 months of exposure, compared to 3 days at baseline. The EMBOLD registrational study for SCN2A and SCN8A-DEEs continues to enroll strongly with topline results expected no later than the first half of 2026.
• Praxis presented a comprehensive set of pre-clinical data spanning 10 different DEE disease models, providing compelling evidence that relutrigine’s anti-seizure mechanism is well suited for broad DEEs. Praxis plans to initiate the EMERALD registrational study in mid-2025.
  • EMERALD will recruit 160 patients in a randomized, placebo-controlled study with a 16-week treatment period to evaluate seizure reduction.
  • Patients will be selected based on clinical phenotype, irrespective of genetic etiology.
  • With a target population exceeding 200,000 patients in the US and precedent from other approved DEE therapies, Praxis conservatively estimates a US market potential of at least $3 billion.
• The company also shared its expectation that relutrigine could potentially be used in combination with any of its DEE ASO programs (elsunersen, PRAX-080, PRAX-090) allowing patients to receive both therapies together for broader clinical benefit.

Elsunersen

• EMBRAVE Part A is enrolling up to 16 patients on a 3:1 drug to sham ratio with once-monthly intrathecal dosing for six months. Recruitment is expected to be complete by mid-year with topline results in the first half of 2026.
• The EMBRAVE3 registrational trial, initiating in mid-2025, will initially enroll patients ages 2-18. Subsequent cohorts will support treatment initiation from birth, reflecting the early onset of SCN2A GoF DEE which can present in-utero or shortly after birth and is often diagnosed within the first three weeks of life.
• With a global addressable population estimated at 5,000 patients, and pricing analogs for other approved ASOs, Praxis conservatively estimates a global market potential of $1 billion.
  

Solidus pre-clinical pipeline

• Praxis plans to nominate a development candidate for its early-stage ASO program PRAX-100 in mid-2025.
  • PRAX-100 is targeting SCN2A loss-of-function (LoF) mutations, a leading cause of monogenetic autism.
  • Praxis shared pre-clinical data from four candidate ASOs showing significant increase in protein levels versus control in a humanized SCN2A mouse model, believed to be sufficient to offset the naturally occurring protein reduction seen in patients with SCN2A LoF mutations.
• Praxis remains on track to nominate development candidates for PRAX-080 and PRAX-090 by the end of 2025. PRAX-080 is targeting PCDH19 mosaic expression and PRAX-090 is designed to address SYNGAP1 LoF mutations.

About Relutrigine (PRAX-562)
Relutrigine is a first-in-class small molecule in development for the treatment of developmental and epileptic encephalopathies (DEEs) as a preferential inhibitor of persistent sodium current, shown to be a key driver of seizure symptoms in severe DEEs. Relutrigine’s mechanism of precision sodium channel (NaV) modulation is consistent with superior selectivity for disease-state NaV channel hyperexcitability. In vivo studies of relutrigine have demonstrated dose-dependent inhibition of seizures up to complete control of seizure activity in SCN2A, SCN8A and other DEE mouse models. Relutrigine has been generally well-tolerated in three Phase 1 studies and has demonstrated biomarker changes indicative of NaV channel modulation. Data from Cohort 1 of the Phase 2 EMBOLD study demonstrated a well-tolerated, robust, short- and long-term improvement in motor seizures in a heavily pre-treated population alongside maintained seizure freedom in some patients with SCN2A- and SCN8A-DEE. Relutrigine has received Orphan Drug Designation (ODD) and Rare Pediatric Disease Designation from the FDA for the treatment of SCN2A-DEE, SCN8A-DEE and Dravet syndrome, and ODD from the European Medicines Agency for the treatment of SCN2A-DEE and SCN8A-DEE. To learn more about the EMBOLD study, please visit https://www.emboldstudy.com/.

About Elsunersen (PRAX-222)
Elsunersen is an antisense oligonucleotide (ASO) designed to selectively decrease SCN2A gene expression, directly targeting the underlying cause of early-onset SCN2A-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. Data from the Part 1 of the EMBRAVE study demonstrated well-tolerated, significant and sustained seizure reduction in patients with SCN2A-DEE. Elsunersen has received Orphan Drug Designation (ODD) and Rare Pediatric Disease Designation (RPD) from the FDA, and ODD and PRIME designations from the European Medicines Agency (EMA) for the treatment of SCN2A-DEE. The Elsunersen program is ongoing under a collaboration with Ionis Pharmaceuticals, Inc. (NASDAQ: IONS), and RogCon, Inc. To learn more about the EMBRAVE study, please visit https://www.embravestudy.org/.

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 epilepsy and movement disorders, 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 our clinical trials, the development of our product candidates and plans to initiate new clinical programs and the anticipated timing of regulatory submissions and interactions, 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 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 were the key results from PRAX's EMBOLD study for relutrigine?

In the EMBOLD study, patients achieved approximately 90% mean seizure reduction from baseline, and the mean longest seizure-free period increased from 3 days to 67 days after 11 months of treatment.

What is the market potential for Praxis Precision Medicines' relutrigine?

Praxis estimates a US market potential of at least $3 billion for relutrigine, based on a target population exceeding 200,000 patients and precedent from other approved DEE therapies.

When will PRAX's EMBRAVE3 trial for elsunersen begin?

The EMBRAVE3 registrational trial is set to initiate in mid-2025, initially enrolling patients ages 2-18, with plans to expand to treatment from birth.

What are the upcoming catalysts for Praxis Precision Medicines (PRAX)?

Key catalysts include PRAX-100 development candidate nomination by mid-2025, EMERALD study initiation in mid-2025, and PRAX-080 and PRAX-090 candidate nominations by end of 2025.

What is the timeline for PRAX's EMBOLD study results?

Topline results from the EMBOLD registrational study for SCN2A and SCN8A-DEEs are expected no later than the first half of 2026.