Pasithea Therapeutics Announces Amendments to Clinical Study Protocol for Phase 1/1B NF1 Clinical Trial

Rhea-AI Summary

Pasithea Therapeutics (NASDAQ:KTTA) amended the clinical protocol for its Phase 1/1b PAS-004 trial in NF1 patients with symptomatic inoperable, incompletely resected or recurrent plexiform neurofibroma.

Changes add higher dose levels (24mg, 32mg), allow longer treatment up to 18 months, expand imaging and CN measurements, and support a planned interim NF1 data update in Q4 2026.

Positive

• Phase 1/1b Part A expanded to include higher PAS-004 doses of 24mg and 32mg
• Protocol now allows treatment in Part A for up to 18 months
• Additional MRI scans and detailed CN measurements to better evaluate tumor response
• Dose-escalation Part A has enrolled and dosed 18 NF1 patients to date
• Company remains on track for an interim NF1 data update in Q4 2026

Negative

• None.

News Market Reaction – KTTA

-8.93%

7 alerts

-8.93% Session close to close

-8.4% Trough in 2 hr 39 min

$17.88M Market Cap

0.6x Rel. Volume

In the Jun 16 session, KTTA declined 8.93%, reflecting a notable negative market reaction. Argus tracked a trough of -8.4% from its starting point during tracking. Our momentum scanner triggered 7 alerts that day, indicating moderate trading interest and price volatility.

Data tracked by StockTitan Argus on the day of publication.

Market Context

The stock moved -8.9% in the session following this news. A negative reaction despite a constructive...

Analysis

The stock moved -8.9% in the session following this news. A negative reaction despite a constructive NF1 protocol expansion fits prior divergence episodes, where positive PAS-004 clinical or designation news coincided with drops of -9.79% and about -29.58%. The pre-news decline of -5.26% also closely tracks the average -4.66% move seen for similar clinical-trial headlines. This pattern underlines how funding needs, past volatility, and risk perceptions can outweigh incremental trial design improvements in the near term.

Key Figures

New higher dose levels: 24mg and 32mg Backfill dose cohorts: 4mg, 8mg, 12mg, 18mg Intermediate dose cohort: 15mg +5 more

8 metrics

New higher dose levels 24mg and 32mg Additional PAS-004 dose levels added to NF1 Part A escalation

Backfill dose cohorts 4mg, 8mg, 12mg, 18mg Completed cohorts in Part A eligible for up to two extra participants

Intermediate dose cohort 15mg Intermediate dose level already enrolled in NF1 Part A

Treatment duration cap 18 months Maximum time patients may remain on PAS-004 in Part A

Initial cohorts dosed 4mg, 8mg, 12mg, 18mg Enrollment and multi-cycle dosing completed at these levels

Additional patients 6 patients Recently enrolled and dosed following protocol amendments

NF1 patients enrolled 18 patients Total enrolled and dosed in dose-escalation Phase 1/1b NF1 trial

Interim data timing Q4 2026 Targeted timing for interim NF1 data update

Previous Clinical trial Reports

5 past events · Latest: Jun 02 (Positive)

Same Type Pattern 5 events

Date	Event	Sentiment	24h Move	Catalyst
Jun 02	Orphan Drug designation	Positive	-9.8%	FDA Orphan Drug Designation for PAS-004 in ALS with potential incentives.
Apr 01	Fast Track designation	Positive	+0.3%	FDA Fast Track for PAS-004 in NF1 plexiform neurofibromas.
Nov 24	Phase 1 safety/PK data	Positive	+45.3%	Completion of Cohort 7 with favorable safety, PK and PD in cancer trial.
Nov 21	NF1 PK tablet data	Positive	-29.6%	Positive tablet PK data in NF1 PAS-004 Phase 1/1b study.
Nov 20	Phase 1 efficacy signal	Positive	-29.6%	Positive Phase 1 data including partial response in advanced cancer study.

24h Move is the share-price change in the day after each event; other market factors may also have contributed.

Pattern Detected

Clinical and designation updates for PAS-004 often had negative or volatile reactions, with 3 divergence events vs. 2 aligned and an average same-tag move of -4.66%.

Recent Company History

Over the past year, Pasithea has steadily advanced PAS-004 through early-stage development. Clinical and regulatory milestones included Fast Track and Orphan Drug designations and multiple Phase 1 data updates with detailed PK, PD, and response metrics across NF1 and advanced cancer settings. Market reactions were mixed: some positive data triggered sharp gains (e.g., a 45.33% move), while others, including regulatory wins, saw double‑digit declines. Today’s NF1 protocol amendment fits this pattern of clinically constructive steps met by uneven trading.

Key Terms

phase 1/1b, dose escalation, open-label, macrocyclic MEK inhibitor, +4 more

8 terms

phase 1/1b medical

"This multicenter, phase 1/1b, open-label study is divided into two parts"

Phase 1/1b describes early-stage clinical testing in humans where researchers first assess a drug’s safety, tolerable dose range and how the body processes it; phase 1b often means small expansion groups to explore the best dose and look for initial signs the treatment might work. For investors, these studies are like the first road tests of a new product—positive results reduce risk and increase value potential, while negative or unclear results raise uncertainty about future development.

dose escalation medical

"update to the dose escalation part of the study (Part A) to allow"

Dose escalation is the process of gradually increasing the amount of a treatment or substance over time. In finance, it can refer to slowly raising investments or commitments to manage risk and assess performance. For investors, understanding dose escalation helps gauge how companies or strategies adjust their approaches, which can impact future growth or stability.

open-label medical

"This multicenter, phase 1/1b, open-label study is divided into two parts"

Open-label describes a situation where everyone involved in a study or process knows the full details, such as who is receiving a treatment or intervention. For investors, understanding whether a project or product is open-label helps gauge the level of transparency and potential biases, influencing trust and decision-making. It’s like knowing whether a test or experiment is conducted openly or behind closed doors.

macrocyclic MEK inhibitor medical

"developing PAS-004, a next-generation macrocyclic MEK inhibitor, today announced"

A macrocyclic MEK inhibitor is a type of cancer drug built around a large ring-shaped molecule that blocks the MEK protein, a key switch in a cell growth pathway often hijacked by tumors. For investors, these drugs matter because they can slow or stop tumor growth where that pathway is active, so clinical results, safety issues, and regulatory decisions can quickly change a biotech’s value—think of it as cutting the fuel line to an engine driving tumor growth.

neurofibromatosis type 1 medical

"trial of PAS-004 in neurofibromatosis type 1 (NF1) patients with symptomatic"

A genetic condition that causes noncancerous tumors to grow on nerves and can lead to skin changes, pain, learning challenges and other complications; severity varies widely from mild to serious. Investors track it because treatments, diagnostics and care pathways for this distinct patient group can drive clinical trial outcomes, regulatory approvals and long‑term revenue, much like a niche market where the size, unmet need and treatment complexity determine potential returns.

plexiform neurofibroma medical

"recurrent plexiform neurofibroma (PN). The amendments include an update"

A plexiform neurofibroma is a typically noncancerous growth that develops along nerves, made up of many tangled nerve fibers and supporting cells; imagine a knot of soft tissue wrapping a nerve like ivy around a branch. It matters to investors because these lesions can cause chronic pain, disability, disfigurement, and sometimes progress to cancer, driving demand for diagnostics, drugs, surgeries and regulatory trials that affect healthcare company revenues and risk profiles.

magnetic resonance imaging (mri) medical

"include additional MRI scans to comprehensively evaluate PN, as well as"

A magnetic resonance imaging (MRI) scan is a medical camera that uses strong magnets and radio waves to create detailed pictures of the body’s organs and tissues without surgery or X-rays. Investors care because MRI machines and the services around them represent significant capital spending, recurring revenue from scans, and influence on clinical trials, hospital budgets, and healthcare reimbursements—factors that affect the financial outlook of medical device makers and providers.

cutaneous neurofibroma medical

"more detailed cutaneous neurofibroma (CN) measurements, including tumor height"

A cutaneous neurofibroma is a benign, soft tumor that grows from nerve tissue just under the skin, often feeling like a small pea or soft bump and sometimes causing pain, itching, or cosmetic changes. For investors, these lesions matter because their frequency, symptoms and treatment needs create markets for drugs, medical devices, surgical services and diagnostics; progress in clinical trials or regulatory approvals can directly affect companies working on therapies or tools to manage them.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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-- Remains on track to release interim NF1 data update in Q4 2026 --
-- Additional dose levels and longer treatment period added --

MIAMI, June 16, 2026 (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 it has amended the clinical study protocol for the Phase 1/1b trial of PAS-004 in neurofibromatosis type 1 (NF1) patients with symptomatic inoperable, incompletely resected, or recurrent plexiform neurofibroma (PN). The amendments include an update to the dose escalation part of the study (Part A) to allow for the enrollment of additional participants at two additional higher dose levels (24mg and 32mg), the ability to backfill completed dose cohorts (4mg, 8mg, 12mg and 18mg) with up to two participants, and the evaluation of intermediate dose levels.  

In addition, the protocol amendments allow patients to remain on treatment for up to 18 months in Part A, and include additional MRI scans to comprehensively evaluate PN, as well as adding more detailed cutaneous neurofibroma (CN) measurements, including tumor height and volume.

Pasithea has completed enrollment and multi-cycle dosing of the initial 4mg, 8mg, 12mg and 18mg cohorts, and enrolled the 24mg cohort and an intermediate 15mg cohort.

“We believe increasing the breadth and depth of Part A of the NF1 study will help inform dose selection for Part B and our future registrational studies,” said Dr. Kartik Krishnan, Chief Medical Officer, Pasithea. “I am pleased that we rapidly enrolled and dosed an additional 6 patients and that the amendments will allow us to provide more comprehensive data in 2026.”

This multicenter, phase 1/1b, open-label study is divided into two parts: a dose-escalation phase (part A) and an expansion cohort phase (part B). To date, the dose-escalation phase has enrolled and dosed 18 patients with NF1.

About NF1- PN
Plexiform neurofibromas (PN) are tumors originating from the nerve sheath that grow through and around nerves and may involve multiple nerve branches. Thirty to fifty percent (30-50%) of patients with NF1 will harbor PNs, which can undergo malignant transformation. PN-related morbidities are primarily caused by the direct impact of the tumor on surrounding structures and can be life-threatening when they compress vital organs or when they become malignant.

About Pasithea Therapeutics Corp.
Pasithea is a clinical-stage biotechnology company primarily focused on the research and development of its lead drug candidate, PAS-004, a next-generation macrocyclic MEK inhibitor intended for the treatment of RASopathies, MAPK pathway-driven tumors, and other diseases. The Company is currently testing PAS-004 in a Phase 1 clinical trial in patients with advanced cancer (NCT06299839), and a Phase 1/1b clinical trial in patients with neurofibromatosis type 1 (NF1)-associated plexiform neurofibromas with symptomatic and inoperable, incompletely resected, or recurrent PN (NCT06961565).

Forward Looking Statements
This press release contains statements that constitute “forward-looking statements” made pursuant to the safe harbor provisions of the Private Securities Litigation Reform Act of 1995. These forward-looking statements include statements regarding the Company’s ongoing Phase 1 clinical trial of PAS-004 in advanced cancer patients, the Company’s ongoing Phase 1/1b clinical trial of PAS-004 in adult NF1 patients, and the safety, tolerability, pharmacokinetic (PK), pharmacodynamics (PD) and preliminary efficacy of PAS-004, as well as all other statements, other than statements of historical fact, regarding the Company’s current views and assumptions with respect to future events regarding its business, as well as other statements with respect to the Company’s plans, assumptions, expectations, beliefs and objectives, the success of the Company’s current and future business strategies, product development, pre-clinical studies, clinical studies, clinical and regulatory timelines, market opportunity, competitive position, business strategies, potential growth and financing opportunities and other statements that are predictive in nature. Forward-looking statements are subject to numerous conditions, many of which are beyond the control of the Company. While the Company believes these forward-looking statements are reasonable, undue reliance should not be placed on any such forward-looking statements, which are based on information available to the Company on the date of this release. These forward-looking statements are based upon current estimates and assumptions and are subject to various risks and uncertainties, including risks that future clinical trial results may not match results observed to date, may be negative or ambiguous, or may not reach the level of statistical significance required for regulatory approval, as well as other factors set forth in the Company’s most recent Annual Report on Form 10-K, Quarterly Reports on Form 10-Q and other filings made with the U.S. Securities and Exchange Commission. Thus, actual results could be materially different. The Company undertakes no obligation to update these statements, whether as a result of new information, future events, or otherwise, after the date of this release, except as required by law.

Pasithea Therapeutics Contact

Patrick Gaynes
Investor Relations
pgaynes@pasithea.com

FAQ

What protocol changes did Pasithea (NASDAQ:KTTA) announce for its PAS-004 NF1 Phase 1/1b trial?

Pasithea expanded the PAS-004 NF1 Phase 1/1b protocol to include higher doses, longer treatment, and more imaging. According to Pasithea, these amendments enhance dose exploration and tumor assessment in patients with plexiform and cutaneous neurofibromas.

Which new PAS-004 dose levels are being tested in Pasithea’s NF1 Phase 1/1b trial (KTTA)?

Pasithea added 24mg and 32mg PAS-004 dose levels in Part A of the NF1 trial. According to Pasithea, it also allows evaluation of intermediate doses and backfilling completed 4mg–18mg cohorts with up to two extra participants each.

How long can NF1 patients now remain on PAS-004 treatment in the KTTA Phase 1/1b study?

NF1 patients in Part A can now stay on PAS-004 treatment for up to 18 months. According to Pasithea, the extended duration supports more comprehensive safety and tumor response evaluation over multiple treatment cycles.

How many NF1 patients have been enrolled in Pasithea’s PAS-004 Phase 1/1b dose-escalation study?

The PAS-004 NF1 dose-escalation phase has enrolled and dosed 18 patients to date. According to Pasithea, initial 4mg, 8mg, 12mg and 18mg cohorts are complete, with 24mg and an intermediate 15mg cohort also enrolled.

What imaging and measurement enhancements were added to the PAS-004 NF1 Phase 1/1b trial (KTTA)?

The protocol now includes additional MRI scans and more detailed cutaneous neurofibroma measurements. According to Pasithea, CN assessments will capture tumor height and volume to better characterize treatment effects on skin lesions.

When does Pasithea plan to provide interim NF1 data from the PAS-004 Phase 1/1b trial?

Pasithea plans an interim NF1 data update in the fourth quarter of 2026. According to Pasithea, the broadened Part A design is intended to inform dose selection for Part B and future registrational studies.