Pasithea Therapeutics Corp. (NASDAQ:KTTA) on Friday shared positive clinical data from its Phase 1/1b study of PAS-004 in adults with neurofibromatosis type 1 (NF1)-associated plexiform neurofibromas (PN) and cutaneous neurofibromas (cNF).
Pasithea presented Study PAS-004-103 (NCT06961565) data at the 2026 European Neurofibromatosis Conference.
NF1 is a rare, progressive genetic condition caused by a spontaneous or inherited mutation in the NF1 gene.
It is associated with a variety of symptoms, including soft lumps on and under the skin (cutaneous neurofibromas) and, in up to 50% of patients, tumors called plexiform neurofibromas (PN) that can develop along nerve sheaths.
These PN can cause clinical issues such as disfigurement, motor dysfunction, pain, airway dysfunction, visual impairment and bladder or bowel dysfunction.
Cutaneous Neurofibroma Reductions Deepen Over Time
Researchers evaluated 15 participants with 71 target cNFs at baseline, measuring length and width in triplicate using digital calipers.
All 15 evaluable patients showed summed target cNF surface area reductions with a 41% median best reduction.
Among eight evaluable patients receiving the planned Phase 2 doses of 4, 8 and 12 mg, the median best reduction was 46%. All six patients receiving 4 or 8 mg had reductions greater than 40%.
Reductions deepened with continued treatment. Among participants followed through 12 cycles, the median reduction in summed target cNF surface area increased from 12% at Cycle 1 to 38% at Cycle 4 and 49% at Cycle 12. In the 4 mg cohort, the median reduction reached 71% at Cycle 15.
Researchers also measured the longest diameter.
At 4, 8 and 12 mg, 27 of 37 target cNFs (73%) shrank at least 25% in longest diameter, meeting the REiNS criterion.
Among the 29 cNFs remaining after eight were resected at Cycle 1 or 6 for pharmacodynamic testing, 24 (83%) met this threshold. The median best reduction in longest diameter among the 29 remaining cNFs was 39%.
Plexiform Neurofibroma Results And Safety
Data showed target PN volume reductions in all 18 evaluable participants. Two patients at 12 and 15 mg met the REiNS partial-response threshold, including a 22.5% reduction at 15 mg on the first on-treatment MRI pending confirmation.
Investigators reported no treatment-related serious adverse events or treatment-related discontinuations, no retinopathy and no adverse events of decreased left ventricular ejection fraction (LVEF).
Through Oct. 7, PAS-004 showed dose-proportional exposure across 4 to 24 mg, a 40-to-60-hour half-life and limited peak-to-trough fluctuations (Cmax/Cmin of 1.5 to 2.0), matching solid tumor findings and supporting once-daily dosing.
FDA Previously Cleared Phase 2 IND
The FDA’s Division of Dermatology and Dentistry previously cleared the IND for Study PAS-004-201, a randomized, double-blind, placebo-controlled Phase 2 trial testing three once-daily doses in about 200 adults with NF1-associated cNF.
Study PAS-004-103 advances toward its randomized two-dose Part B expansion, with resected cNF pharmacodynamic analyses expected in 2027.
KTTA Price Action: Pasithea Therapeutics shares were up 5.02% at $0.55 at last check Friday, according to Benzinga Pro data.
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