Acadia Pharmaceuticals Inc. (NASDAQ:ACAD) today announced that it will present multiple original data presentations spanning its portfolio at the 2026 American Academy of Neurology (AAN) Annual Meeting, taking place April 18–22, 2026 in Chicago, IL.

The Company will present real-world data from a sub-group analysis of the ongoing, Phase 4, prospective, observational, open-label LOTUS study evaluating the benefits and tolerability of DAYBUE^® (trofinetide) in adults with Rett syndrome in routine clinical practice. In support of NUPLAZID^® (pimavanserin) in Parkinson's disease psychosis (PDP), Acadia will present exploratory analyses evaluating heterogeneity in treatment response trajectories and the impact of baseline sleep disturbances among PDP patients treated with pimavanserin. The Company is also debuting translational and pharmacokinetic research supporting the continued development of ACP-711, an investigational drug, for essential tremor. Collectively, these data reflect Acadia's ongoing commitment to advancing scientific knowledge across a wide range of neurological conditions.

AAN Poster Presentations

P11.005: Real-world Benefits and Tolerability of Trofinetide for the Treatment of Adults with Rett Syndrome: the LOTUS Study, Wednesday, April 22, 11:45 AM – 12:45 PM CT
P11.006: Response Trajectories of Patients with Parkinson's Disease Psychosis Treated with Pimavanserin: An Exploratory Cluster Analysis, Wednesday, April 22, 11:45 AM – 12:45 PM CT
P11.007: Impact of Baseline Sleep Disturbances on Pimavanserin Response in Parkinson's Disease Psychosis: A Post Hoc Analysis, Wednesday, April 22, 11:45 AM – 12:45 PM CT
P7.007: Development of ACP-711, a Selective Modulator of GABA-A Receptor a3, for Essential Tremor: Use of First-in-Human Phase 1 Pharmacokinetics and Pharmacodynamics to Identify Target Dose/Exposure, Tuesday, April 21, 8:00 AM – 9:00 AM CT
P8.012: Mechanism of Action, Preclinical Efficacy, and Safety Evaluation of ACP-711 (SAN711): A Novel GABAA Subunit a3 Selective Modulator, Tuesday, April 21, 11:45 AM – 12:45 PM CT

About DAYBUE^® (trofinetide) and DAYBUE^® STIX (trofinetide)

Trofinetide is a synthetic analog of the N-terminal tripeptide of insulin-like growth factor-1. The mechanism by which trofinetide exerts therapeutic effects in patients with Rett syndrome is unknown. In animal studies, trofinetide has been shown to increase branching of dendrites and synaptic plasticity signals.¹

Indication and Important Safety Information for DAYBUE^® (trofinetide) and DAYBUE^®STIX (trofinetide)

Indication

DAYBUE and DAYBUE STIX are indicated for the treatment of Rett syndrome in adults and pediatric patients 2 years of age and older.

Important Safety Information

Warnings and Precautions
- Diarrhea: In a 12-week study and in long-term studies, 85% of patients treated with DAYBUE experienced diarrhea. In those treated with DAYBUE, 49% either had persistent diarrhea or recurrence after resolution despite dose interruptions, reductions, or concomitant antidiarrheal therapy. Diarrhea severity was mild or moderate in 96% of cases. In the 12-week study, antidiarrheal medication was used in 51% of patients treated with DAYBUE.
  
  Advise patients to stop laxatives before starting DAYBUE or DAYBUE STIX. If diarrhea occurs, patients should notify their healthcare provider, consider starting antidiarrheal treatment, and monitor hydration status and increase oral fluids, if needed. Interrupt, reduce dose, or discontinue DAYBUE or DAYBUE STIX if severe diarrhea occurs or if dehydration is suspected.
- Vomiting: In a 12-week study, vomiting occurred in 29% of patients treated with DAYBUE and in 12% of patients who received placebo.
  
  Patients with Rett syndrome are at risk for aspiration and aspiration pneumonia. Aspiration and aspiration pneumonia have been reported following vomiting in patients being treated with DAYBUE. Interrupt, reduce dose, or discontinue DAYBUE or DAYBUE STIX if vomiting is severe or occurs despite medical management.
- Weight Loss: In the 12-week study, 12% of patients treated with DAYBUE experienced weight loss of greater than 7% from baseline, compared to 4% of patients who received placebo. In long-term studies, 2.2% of patients discontinued treatment with DAYBUE due to weight loss. Monitor weight and interrupt, reduce dose, or discontinue DAYBUE or DAYBUE STIX if significant weight loss occurs.
Adverse Reactions: The common adverse reactions (≥5% for DAYBUE-treated patients and at least 2% greater than in placebo) reported in the 12-week study were diarrhea (82% vs 20%), vomiting (29% vs 12%), fever (9% vs 4%), seizure (9% vs 6%), anxiety (8% vs 1%), decreased appetite (8% vs 2%), fatigue (8% vs 2%), and nasopharyngitis (5% vs 1%).
Drug Interactions: Effect of DAYBUE and DAYBUE STIX on other Drugs
- Trofinetide, a weak inhibitor of CYP3A and an inhibitor of P-gp, can increase the plasma concentrations of CYP3A and/or P-gp substrates (e.g., loperamide), which may increase the risk of adverse reactions associated with these substrates .
  
  Closely monitor patients when DAYBUE or DAYBUE STIX is administered concomitantly with sensitive CYP3A and/or P-gp substrates for which a minimal increase in substrate plasma concentration (i.e., drugs with a narrow therapeutic index) may lead to serious adverse reactions.
Use in Specific Population: Renal Impairment
- DAYBUE and DAYBUE STIX are not recommended for patients with severe renal impairment.

DAYBUE is available as an oral solution (200 mg/mL).

DAYBUE STIX for oral solution powder is available in 5,000 mg, 6,000 mg, and 8,000 mg packets.

Please read the full Prescribing Information also available at DAYBUEhcp.com.

About NUPLAZID^®(pimavanserin)

Pimavanserin is a selective serotonin inverse agonist and antagonist preferentially targeting 5-HT2A receptors. These receptors are thought to play an important role in neuropsychiatric disorders. In vitro, pimavanserin demonstrated no appreciable binding affinity for dopamine (including D2), histamine, muscarinic, or adrenergic receptors. Pimavanserin was approved for the treatment of hallucinations and delusions associated with Parkinson's disease psychosis by the U.S. Food and Drug Administration in April 2016 under the trade name NUPLAZID.

Indication

NUPLAZID is indicated for the treatment of hallucinations and delusions associated with Parkinson's disease psychosis.

Important Safety Information

WARNING: INCREASED MORTALITY IN ELDERLY PATIENTS WITH DEMENTIA-RELATED PSYCHOSIS

Elderly patients with dementia-related psychosis treated with antipsychotic drugs are at an increased risk of death.
NUPLAZID is not approved for the treatment of patients with dementia who experience psychosis unless their hallucinations and delusions are related to Parkinson's disease.
Contraindication: NUPLAZID is contraindicated in patients with a history of a hypersensitivity reaction to pimavanserin or any of its components. Rash, urticaria, and reactions consistent with angioedema (e.g., tongue swelling, circumoral edema, throat tightness, and dyspnea) have been reported.
Warnings and Precautions: QT Interval Prolongation
- NUPLAZID prolongs the QT interval. The use of NUPLAZID should be avoided in patients with known QT prolongation or in combination with other drugs known to prolong QT interval (e.g., Class 1A antiarrhythmics, Class 3 antiarrhythmics, certain antipsychotics or antibiotics).
- NUPLAZID should also be avoided in patients with a history of cardiac arrhythmias, as well as other circumstances that may increase the risk of the occurrence of torsade de pointes and/or sudden death, including symptomatic bradycardia, hypokalemia or hypomagnesemia, and presence of congenital prolongation of the QT interval.
Adverse Reactions: The adverse reactions (≥2% for NUPLAZID and greater than placebo) were peripheral edema (7% vs 2%), nausea (7% vs 4%), confusional state (6% vs 3%), hallucination (5% vs 3%), constipation (4% vs 3%), and gait disturbance (2% vs <1%).
Drug Interactions:
- Coadministration with strong CYP3A4 inhibitors increases NUPLAZID exposure. Reduce NUPLAZID dose to 10 mg taken orally as one tablet once daily.
- Coadministration with strong or moderate CYP3A4 inducers reduces NUPLAZID exposure. Avoid concomitant use of strong or moderate CYP3A4 inducers with NUPLAZID.

Dosage and Administration

Recommended dose: 34 mg capsule taken orally once daily, without titration, with or without food.

NUPLAZID is available as 34 mg capsules and 10 mg tablets.

Please read the full Prescribing Information, including Boxed WARNING, also available at NUPLAZIDhcp.com.

About Acadia Pharmaceuticals

Acadia is committed to turning scientific promise into meaningful innovation that makes the difference for underserved neurological and rare disease communities around the world. Our commercial portfolio includes the first and only FDA-approved treatments for Parkinson's disease psychosis and Rett syndrome. We are developing the next wave of therapeutic advancements with a robust and diverse pipeline that includes mid- to late-stage programs in Alzheimer's disease psychosis and Lewy body dementia psychosis, along with earlier-stage programs that address other underserved patient needs. At Acadia, we're here to be their difference. For more information, visit us at acadia.com and follow us on LinkedIn and X.

References

Acadia Pharmaceuticals Inc., Data on file. Study Report 2566-026. 2010.

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Investor Contact:

Acadia Pharmaceuticals Inc.

Al Kildani

(858) 261-2872

ir@acadia-pharm.com

Acadia Pharmaceuticals Inc.

Jessica Tieszen

(858) 261-2950

ir@acadia-pharm.com

Media Contact:

Acadia Pharmaceuticals Inc.

Deb Kazenelson

(818) 395-3043

media@acadia-pharm.com

Acadia Pharmaceuticals to Present Data at the 2026 American Academy of Neurology (AAN) Annual Meeting