4 June 2026

Designation aims to accelerate the development of therapies for rare diseases

• PAS-004, an experimental drug for ALS, received FDA orphan drug designation to accelerate its development.
• The therapy targets inflammation and TDP-43 protein clumps, hallmarks of ALS progression.
• A Phase 1 clinical trial will assess PAS-004’s safety and tolerability in ALS patients.

PAS-004, an experimental therapy that Pasithea Therapeutics is developing to address inflammation and TDP-43 protein clumps, has received orphan drug designation by the U.S. Food and Drug Administration for the treatment of amyotrophic lateral sclerosis (ALS).

The status aims to accelerate the development of therapies for rare diseases, or those affecting fewer than 200,000 people in the U.S., for which there are no effective therapies available. It provides developers with a range of incentives, including tax credits for qualified clinical trials, exemptions from certain fees, and seven years of market exclusivity if the medication is ultimately approved.

Pasithea received nearly $1 million from the ALS Association last year to support the development of PAS-004 as a treatment for ALS. The funding is expected to support a Phase 1 clinical trial involving a small group of patients to gather safety, dosing, and biomarker data that may help move the therapy into more advanced stages of development.

“ALS remains a devastating neurodegenerative disease with limited treatment options and significant unmet medical need,” Tiago Reis Marques, MD, PhD, Pasithea’s CEO, said in a company press release. “This designation further supports our efforts to explore the potential of PAS-004 in ALS and other serious diseases where dysregulation of the MAPK pathway may play an important role.”

PAS-004 targets key protein linked to inflammation

Inflammation and the abnormal accumulation of TDP-43 protein clumps are hallmarks of ALS and are believed to play an important role in driving disease onset and progression.

PAS-004 is designed to address those issues by targeting the MEK protein, which is believed to contribute to TDP-43-related neurodegeneration and neuroinflammation. While exact results have not been shared, PAS-004 has “delivered significant and promising results” in a mouse model of ALS, the company said in a previous press release.

Pasithea is now working to launch a Phase 1 clinical trial in people with the disease. Late last year, the company said the trial is expected to enroll 12 participants who will receive three dose levels of the experimental medication and will be followed for about 6.5 months.

The main goal is to evaluate PAS-004’s safety and tolerability. Researchers will also measure changes in ALS Functional Rating Scale Revised scores, a measure of physical function, and levels of neurofilament light chain, a biomarker of nerve damage.

PAS-004 is also being tested in two other Phase 1 clinical trials, one in advanced cancer and another in neurofibromatosis type 1, a condition that causes tumors to grow on nerves.

                                                                                                                      Source: ALS News Today