On September 8, 2025 Pasithea Therapeutics Corp. (NASDAQ: KTTA) ("Pasithea" or the "Company"), a clinical-stage biotechnology company developing PAS-004, a next-generation macrocyclic MEK inhibitor reported that the external Safety Review Committee recommended that the Company’s Phase 1/1b open label study to assess the safety, tolerability, pharmacokinetics (PK) and pharmacodynamics (PD) of PAS-004, in adult participants with neurofibromatosis type 1 (NF1) should proceed to Cohort 2, 8mg tablet, without modification (Press release, Pasithea Therapeutics, SEP 8, 2025, View Source [SID1234655833]). This recommendation was based on the review of the safety data from three patients from Cohort 1 and the absence of any dose limiting toxicities (DLT’s).
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"We are seeing substantial enrollment demand and have already enrolled the first three Cohort 2 patients," stated Dr. Tiago Reis Marques, Chief Executive Officer of Pasithea.
About the Phase 1/1b Clinical Trial in Adult NF1 Patients
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 NF1 participants with at least one and up to two additional target plexiform neurofibromas (PNs) that are symptomatic and inoperable, incompletely resected, or recurrent. Secondary objectives are (i) to identify the recommended Part B dose ("RPBD") or Maximum Tolerated Dose (MTD) of PAS-004, (ii) to characterize the PK and PD profile of PAS-004, (iii) to evaluate the preliminary efficacy of PAS-004 on target PN volume, (iv) to evaluate the preliminary efficacy of PAS-004 on the size, appearance, and associated symptoms of cutaneous neurofibromas (CNs), and (v) to evaluate the impact of PAS-004 on quality of life ("QOL") and any physical symptoms attributed to the target PN. Experimental objectives are (i) to evaluate the impact of PAS-004 on QOL and any physical symptoms attributed to CNs, (ii) to evaluate the impact of PAS-004 on pain and function attributed to PNs, and (iii) to investigate PAS-004 effects on CN tumor cellular and molecular biology.
The trial will be conducted in two parts. In Part A, following a screening period of up to 28 days, up to 24 eligible participants will be enrolled sequentially to receive one of four planned dose levels of PAS-004 tablets (4mg, 8mg, 12 mg, 18mg) in a modified 3+3 design. Part A will identify the recommended RPBD. During Part B, approximately 24 eligible participants will be enrolled in parallel to receive one of two planned dose levels of PAS-004 tablets. Participants will be dosed at the RPBD level and at a dose level below the RPBD for up to six continuous 28-day treatment cycles. Part B will identify the recommended phase 2 dose (RP2D).
The study is planned to be conducted at five clinical trial sites in Australia, South Korea, and the U.S.