Pasithea Therapeutics: Phase 1/1b Study Proceeds to Cohort 2 Without Modification

Pasithea Therapeutics has announced that its Phase 1/1b study for PAS-004, a next-generation MEK inhibitor, will escalate to the next dose level of 8mg tablets based on the Safety Review Committee's recommendation. The initial interim clinical data from the first two cohorts is expected in Q1 2026. The study aims to assess the safety, tolerability, pharmacokinetics, and pharmacodynamics of PAS-004 in adult participants with neurofibromatosis type 1 (NF1).

Pasithea Therapeutics Corp. (NASDAQ: KTTA) has announced that its Phase 1/1b clinical trial of PAS-004, a next-generation macrocyclic MEK inhibitor, will proceed to the next dose level of 8mg tablets. The external Safety Review Committee recommended this escalation based on the review of safety data from three patients in Cohort 1, which showed no dose-limiting toxicities (DLTs) [1].

The primary objective of the Phase 1/1b study (NCT06961565) is to evaluate the safety and tolerability of PAS-004 when administered for one 28-day treatment cycle in adult participants with neurofibromatosis type 1 (NF1). The study also aims to identify the recommended Phase 2 dose (RP2D) and assess the pharmacokinetics (PK) and pharmacodynamics (PD) profile of PAS-004. Additionally, it will evaluate the preliminary efficacy of PAS-004 on target plexiform neurofibromas (PNs) and cutaneous neurofibromas (CNs), as well as its impact on quality of life (QOL) and physical symptoms [1].

The study will be conducted in two parts. Part A will enroll up to 24 participants to receive one of four planned dose levels of PAS-004 tablets (4mg, 8mg, 12mg, 18mg) in a modified 3+3 design to identify the recommended Part B dose (RPBD). Part B will enroll approximately 24 participants in parallel to receive one of two planned dose levels of PAS-004 tablets at the RPBD level and at a dose level below the RPBD for up to six continuous 28-day treatment cycles to identify the recommended phase 2 dose (RP2D) [1].

The initial interim clinical data from the first two cohorts is expected in Q1 2026. Pasithea Therapeutics has already enrolled the first three Cohort 2 patients, indicating substantial enrollment demand [1].

Pasithea Therapeutics is primarily focused on the research and development of its lead drug candidate, PAS-004, which is intended for the treatment of RASopathies, MAPK pathway-driven tumors, and other diseases. The company is currently testing PAS-004 in a Phase 1 clinical trial in advanced cancer patients (NCT06299839) and a Phase 1/1b clinical trial in adult patients with NF1-associated plexiform neurofibromas (NCT06961565) [1].

References:
[1] https://ir.pasithea.com/news-events/press-releases/detail/127/pasithea-therapeutics-announces-enrollment-of-cohort-2
[2] https://www.globenewswire.com/news-release/2025/09/08/3145990/0/en/Pasithea-Therapeutics-Announces-Enrollment-of-Cohort-2-following-Positive-Safety-Review-Committee-SRC-Recommendation-for-its-Ongoing-Phase-1-1b-Clinical-Trial-of-PAS-004-in-Adult-N.html