KTTA

-- PAS-004 shows up to 91% inhibition of pERK, confirming substantial target engagement -- -- One patient in cohort 4A with stage 4 KRAS G12R mutated pancreatic cancer achieves over 5 months of stable disease with tumor volume reduction of -9.8% -- MIAMI, May 06, 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 for the treatment of neurofibromatosis type 1 (NF1) and other MAPK pathway driven cancer indications, today announced positive interim pharmacodynamic (PD) data from its ongoing Phase 1 trial of PAS-004 in advanced cancer patients. The data includes results from cohorts 3 and 4A, evaluating 8mg and 15mg capsules, as well as cohort 4B evaluating 4mg tablets, and demonstrates strong target engagement consistent with PAS-004’s favorable pharmacological profile. Inhibition of ERK phosphorylation (pERK) is widely recognized as a gold-standard PD biomarker for assessing MEK inhibitor activity. To evaluate target engagement, pERK levels were measured in peripheral blood mononuclear cells (PBMCs) collected from patients at baseline and steady-state at day 22. Preliminary results demonstrate robust pERK inhibition, with reductions in pERK levels of up to 91% even at the 8mg dose level, in line with a previous developed PK/PD model, confirming substantial target engagement in patients receiving PAS-004. Pharmacodynamic activity is supported by encouraging preliminary clinical observations, with several patients achieving stable disease and tumor shrinkage while on PAS-004 treament. Notably, one patient in cohort 4A (15mg capsule) with stage 4 KRAS G12R-mutated pancreatic cancer, having progressive disease while on three prior lines of therapy, achieved a tumor volume reduction of -9.8% over 5 months of PAS-004 treatment and currently remains on study. “With today’s update, we are pleased that PAS-004 has demonstrated clinically meaningful reductions in pERK levels at dose levels that are both well-tolerated and safe, with no rash observed,” said Dr. Tiago Reis Marques, Chief Executive Officer of Pasithea. “We believe PAS-004’s profile offers the potential to finely modulate MAPK pathway activity, enabled by its previously reported long half-life and favorable pharmacokinetic (PK) profile with a Cmax/Cmin ratio...