On November 24, 2025 Pasithea Therapeutics Corp. (Nasdaq: KTTA) ("Pasithea" or the "Company"), a clinical-stage biotechnology company developing PAS-004, a next-generation macrocyclic oral MEK inhibitor for the treatment of neurofibromatosis type 1-associated plexiform neurofibromas (NF1-PN), reported positive safety, PK and PD data from Cohort 7 (37mg capsules) in its ongoing first-in-human trial evaluating PAS-004 in patients with MAPK pathway-driven advanced solid tumors with a documented RAS, NF1 or RAF mutation, or in patients who have failed prior BRAF/MEK inhibition (NCT06299839).
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Dr. Tiago Reis Marques, Chief Executive Officer of Pasithea commented, "We are highly encouraged by the initial safety data generated in Cohort 7 (37mg capsules), where zero treatment-related adverse events have been observed during the DLT period. Furthermore, PD data demonstrates the pharmacological profile we believe is necessary to achieve consistent pathway inhibition over the 24-hour dosing period, while avoiding both periods of excessive suppression and periods of insufficient target engagement. We believe this balanced profile will be critical for achieving clinical efficacy while minimizing the most commonly observed adverse events associated with MEK inhibitors. We believe PAS-004 is particularly well suited for the treatment of diseases involving the MAPK pathway that require chronic dosing over long periods of time, where sustained long-term pathway suppression at safe and well-tolerated doses is required."
PAS-004 has demonstrated in Cohort 7 (37mg capsules):
Safety and Tolerability Results:
PAS-004 was safe and well tolerated with no dose limiting toxicities (DLTs), and no treatment-related adverse events observed during the DLT period.
After reviewing cohort 7 data, the Safety Review Committee recommended to proceed to Cohort 8, 45mg capsules, without modification.
Pharmacodynamics (PD) Results:
At steady-state, individual patient plasma data showed PAS-004 inhibiting phosphorylated extracellular signal-regulated kinase (pERK) at a level of 80% near Cmax.
At steady-state, individual patient plasma data showed PAS-004 inhibiting pERK at a level above 60% at Cmin (24-hour postdose).
Pharmacokinetics (PK) Results:
Linear PK and dose-proportionality.
PK curve with Cmax/Cmin ratio <2.
AUC: 6,690 ng*h/mL; Cmax: 313 ng/mL; Cmin: 260 ng/mL.
Graph 1 below represents the complete PAS-004 dose escalation curve at steady state in our ongoing Phase 1 trial in advanced cancer patients.
(Press release, Pasithea Therapeutics, NOV 24, 2025, View Source [SID1234660904])