8-K: Pasithea Expands NF1 Trial to South Korea, Doses First Patient

Pasithea Therapeutics Corp. announced the activation of two clinical trial sites in South Korea for its Phase 1/1b study of PAS-004 in adult neurofibromatosis type 1 patients, with the first patient dosed.

Summary

• Pasithea Therapeutics Corp. activated two clinical trial sites in South Korea, Asan Medical Centre and Severance Hospital Yonsei University Health System, for its Phase 1/1b open-label study of PAS-004.
• These South Korean sites are now actively recruiting participants for the study in adult patients with neurofibromatosis type 1 (NF1) with symptomatic and inoperable, incompletely resected, or recurrent plexiform neurofibromas.
• The first patient in South Korea has been dosed in the NF1 Trial.
• The NF1 Trial is currently enrolling patients in Cohort 2 (8mg tablet) following a recommendation by the external Safety Review Committee to proceed past Cohort 1 (4mg tablet) without modification.
• Initial interim clinical data from the first two cohorts of the NF1 Trial is expected in the first quarter of 2026.
• The Phase 1/1b study (NCT06961565) aims to evaluate the safety, tolerability, pharmacokinetics (PK), pharmacodynamics (PD), and preliminary efficacy of PAS-004.
• Part A (dose escalation) will enroll up to 24 eligible participants sequentially across four planned dose levels of PAS-004 tablets (4mg, 8mg, 12mg, 18mg).
• Part B (expansion phase) will enroll approximately 24 eligible participants in parallel at the recommended Part B dose (RPBD) and a dose level below the RPBD.
• The study is planned to be conducted at five clinical trial sites across Australia, South Korea, and the U.S.

Sentiment

Score: 7

Explanation: The announcement reflects positive operational progress in a key clinical trial, including international expansion and a favorable safety review, which de-risks the early stages of development. However, it is still an early-stage trial, and definitive efficacy data is pending.

Positives

• Expansion of the Phase 1/1b NF1 clinical trial into South Korea, a significant market with an estimated 10,000 NF1 patients, potentially accelerating patient enrollment.
• Activation of two world-class clinical trial sites in South Korea, Asan Medical Centre and Severance Hospital Yonsei University Health System, known for their research leadership and large NF1 caseloads.
• Dosing of the first patient in South Korea indicates tangible progress in the clinical trial's execution and patient recruitment.
• The external Safety Review Committee recommended proceeding to Cohort 2 (8mg tablet) without modification, suggesting a favorable initial safety and tolerability profile for Cohort 1 (4mg tablet).
• PAS-004 is described as a next-generation macrocyclic MEK inhibitor with a distinct pharmacokinetic profile and a more convenient dosing regimen, which may offer important benefits over existing treatments for NF1 patients.

Risks

• Future clinical trial results may not match results observed to date, may be negative or ambiguous.
• Clinical trial results may not reach the level of statistical significance required for regulatory approval.
• Other factors set forth in the Company's most recent Annual Report on Form 10-K, Quarterly Report on Form 10-Q, and other filings made with the U.S. Securities and Exchange Commission (SEC) could materially affect actual results.

Future Outlook

Initial interim clinical data from the first two cohorts of the NF1 Trial is expected in the first quarter of 2026. The company believes its clinical sites in South Korea will play a pivotal role in the trial's success due to access to world-class facilities and an estimated 10,000 NF1 patients. The company looks forward to advancing meaningful treatment options for the NF1 community and continues its ongoing Phase 1 clinical trial of PAS-004 in advanced cancer patients, expecting positive safety, tolerability, pharmacokinetic (PK), pharmacodynamics (PD), and preliminary efficacy results for PAS-004.

Management Comments

• Professor Lee Beom-Hee (Department of Pediatrics at Asan Medical Center): "I am very pleased to partner with the Pasithea team to initiate testing of PAS-004 in adult patients with plexiform neurofibromas associated with NF1 at Asan Medical Center. Our institution has the largest NF1 caseload in South Korea and a long history of research leadership in this field. Our team was among the first to report the therapeutic benefits of MEK inhibition on neurocognitive decline, caf-au-lait spots, and growth retardation caused by neurofibromatosis. We are eager to evaluate PAS-004, a next-generation MEK inhibitor that to date has demonstrated a distinct pharmacokinetic profile and a more convenient dosing regimen, which we believe may provide important benefits for our NF1 patients."
• Dr. Tiago Reis Marques (Chief Executive Officer of Pasithea): "With access to world-class facilities and an estimated 10,000 NF1 patients in South Korea, we believe our clinical sites in the country will play a pivotal role in the success of this trial. We are excited to include South Korean patients in our NF1 study and look forward to advancing meaningful treatment options for this community."

Industry Context

The expansion of Pasithea's Phase 1/1b NF1 trial into South Korea aligns with a broader industry trend of globalizing clinical trials to access diverse patient populations and leverage specialized medical centers. The development of PAS-004, a next-generation MEK inhibitor, positions Pasithea in a competitive landscape with existing MEK inhibitors like selumetinib (Koselugo), which is approved for NF1. The focus on a distinct pharmacokinetic profile and convenient dosing suggests an attempt to differentiate PAS-004 and potentially offer an improved therapeutic option for patients with RASopathies and MAPK pathway-driven diseases.

Comparison to Industry Standards

• The primary industry benchmark for NF1-associated plexiform neurofibromas is AstraZeneca's Koselugo (selumetinib), an approved MEK inhibitor.
• Pasithea's PAS-004 is positioned as a 'next-generation' MEK inhibitor, aiming to offer potential advantages over existing treatments.
• The company highlights PAS-004's 'distinct pharmacokinetic profile and a more convenient dosing regimen' as potential benefits compared to current standards, which could improve patient compliance and outcomes.

Stakeholder Impact

• Shareholders: The positive clinical trial progress and expansion into a new, significant market could enhance investor confidence in the company's drug pipeline and long-term prospects.
• Patients (NF1): Offers potential hope for a new, potentially improved treatment option for neurofibromatosis type 1, particularly for those with symptomatic and inoperable plexiform neurofibromas.
• Medical Community: Provides new research opportunities and contributes to the global understanding and treatment options for NF1, especially within South Korea's medical and research institutions.

Next Steps

• Actively recruit NF1 trial participants at the newly activated South Korean clinical sites.
• Continue enrolling patients in Cohort 2 (8mg tablet) of the NF1 Trial.
• Await initial interim clinical data from the first two cohorts of the NF1 Trial, expected in the first quarter of 2026.
• Proceed with dose escalation in Part A (up to 18mg) and subsequently to Part B (expansion phase) to identify the Recommended Part B Dose (RPBD) and Recommended Phase 2 Dose (RP2D).

Key Dates

Recommendation

The announcement provides positive operational updates regarding the expansion and progression of the PAS-004 NF1 clinical trial, including the dosing of the first patient in South Korea and a favorable safety review for Cohort 1. This de-risks the early stages of the trial to some extent and expands the potential patient pool. However, these are still early-stage (Phase 1/1b) results, and significant clinical data (expected Q1 2026) is yet to be released. While the news is encouraging, it does not yet provide definitive efficacy data to warrant a stronger recommendation. Investors should hold and await further clinical milestones and data readouts.

Keywords

Pasithea Therapeutics, KTTA, PAS-004, Neurofibromatosis Type 1, NF1, Plexiform Neurofibromas, Clinical Trial, Phase 1/1b, MEK Inhibitor, Biotechnology, South Korea, RASopathies, MAPK pathway