Pasithea Announces Its PAS-004 Shows Early Activity And Durable Disease Stability In Heavily Pretreated Solid Tumors, Including BRAF-Mutated Melanoma, With Favorable Safety And Pharmacokinetics In Ongoing Phase 1 Dose Escalation Trial

-- PAS-004 demonstrates preliminary clinical activity as a monotherapy in patients with heavily pre-treated, refractory solid tumors --

-- One patient in cohort 4A (15mg capsule) with stage 4 BRAF-mutated melanoma, who had progressed after two prior lines of therapy, including a prior MEK inhibitor + BRAF inhibitor combination therapy, achieves over 5 months of stable disease with tumor volume reduction of -14.9% and remains on treatment --

-- PAS-004 pharmacokinetics profile potentially supports a prolonged target engagement at well-tolerated doses --

MIAMI, June 02, 2025 (GLOBE NEWSWIRE) -- Pasithea Therapeutics Corp. (NASDAQ:KTTA) ("Pasithea" or the "Company"), a clinical-stage biotechnology company developing PAS-004, a next-generation macrocyclic MEK inhibitor, today announced updated interim results from its ongoing dose escalation Phase 1 study evaluating PAS-004 in advanced cancer patients in a poster presentation at the American Society of Clinical Oncology (ASCO) 2025 Annual Meeting

The Phase 1 clinical trial is a multi-center, open-label, dose escalation, modified 3+3 study design to evaluate the safety, tolerability, pharmacokinetic (PK), pharmacodynamic (PD), and preliminary efficacy of PAS-004 in patients with MAPK pathway-driven advanced solid tumors with a documented RAS, NF1 or RAF mutation, or patients who have failed BRAF/MEK inhibition (NCT06299839).

As of the cut-off date of April 2, 2025, a total of 21 patients had been enrolled and received at least one dose of PAS-004 in six cohorts (Capsules: 2mg, 4mg, 8mg, 15mg, 22mg / Tablets: 4mg). The most common cancer diagnosis was pancreatic cancer (28.6%), colorectal cancer (28.6%), and melanoma (23.8%).

All treatment-related adverse events (AEs) have been either grade 1 or grade 2. No known MEK inhibitor class-related AEs such as ocular toxicities, cardiotoxicities, and skin toxicities were observed during the DLT observation period. No DLTs were reported, and dose escalation is ongoing.

Preliminary PAS-004 PK analysis suggests linear PK with an estimated half-life in excess of 60 hours. The Cmax (peak) to Cmin (trough) ratio was below 2 at steady state in all dose levels and has achieved potentially sufficient exposures for target engagement. This is supported by previously reported preliminary pERK inhibition observed in cohort 3 (8mg capsule), with pERK inhibition of up to 91%.