Acadia Pharmaceuticals Announces Allowance of U.S. Patent Covering Weight-Banded Dosing of Trofinetide, extending U.S. patent protections to March 2041

-- The allowance strengthens the intellectual property portfolio for trofinetide and extends protections in the U.S. from July 2036 to March 2041

SAN DIEGO, September 28, 2026--Acadia Pharmaceuticals Inc. (Nasdaq: ACAD) today announced that the United States Patent and Trademark Office (USPTO) has issued a Notice of Allowance for U.S. Patent Application No. 17/590,496, titled "Methods and Compositions for Treatment of Rett Syndrome." The Notice of Allowance indicates that the USPTO has determined that the application meets the requirements for patentability, and the patent is expected to issue following completion of standard administrative steps.

The patent application covers weight-banded dosing of trofinetide for the treatment of Rett syndrome. Following issuance and including six months of pediatric exclusivity, the patent is expected to provide protection for trofinetide in the United States through March 28, 2041, extending patent protections by almost five years. Trofinetide is also protected by a method of use patent for the treatment of Rett syndrome, which expires in July 2036.

"This Notice of Allowance is an important addition to the intellectual property protections for trofinetide and reflects our commitment to supporting both current formulations of DAYBUE and the Rett syndrome community for the long term," said Catherine Owen Adams, Chief Executive Officer of Acadia. "We are pleased that this patent is expected to extend protections for trofinetide in the United States from 2036 into 2041."

The Notice of Allowance relates to the weight-banded dosing regimen used for trofinetide, which is marketed in the United States as DAYBUE® and DAYBUE® STIX for the treatment of Rett syndrome in adults and pediatric patients 2 years of age and older.

About Rett Syndrome

Rett syndrome is a rare, complex, neurodevelopmental disorder and occurs in approximately one of every 10,000 to 15,000 female births worldwide.1-3 A child with Rett syndrome generally exhibits an early period of apparently normal development until six to 18 months, when many of their skills seem to slow down or stagnate. This is typically followed by a regression phase when the child loses acquired communication skills and purposeful hand use. The child may then experience a plateau period in which they could show mild recovery in cognitive interests, but body movements remain severely diminished. As they age, those individuals living with Rett may continue to experience a stage of motor deterioration, which can last the rest of the patient's life.2 Rett syndrome is typically caused by a genetic mutation on the MECP2 gene.4 In preclinical studies, deficiency in MeCP2 function is thought to lead to impairment in synaptic communication and brain plasticity, and the deficits in synaptic function may be associated with Rett manifestations.4-6