Acadia Pharmaceuticals (NASDAQ: ACAD) details R&D head’s planned retirement and transition

Rhea-AI Filing Summary

Acadia Pharmaceuticals Inc. announced the planned retirement of Elizabeth H.Z. Thompson, Ph.D., its Head of Research and Development. Dr. Thompson, who joined the company in 2024, is retiring for personal reasons and will remain in her role during a transitional period until a successor is appointed.

After her retirement, Acadia plans to retain Dr. Thompson as a consultant through at least the end of 2026 to support continuity, including through the planned readout of the Phase 2 clinical study of remlifanserin in Alzheimer’s disease psychosis and into early Phase 3 execution. Ongoing clinical trials, including Phase 2 studies of remlifanserin in Alzheimer’s disease psychosis and Lewy Body Dementia Psychosis, are continuing as planned, and the company has begun a search for a new Head of Research and Development.

Insights

Biopharma governance and R&D strategy analyst

Acadia discloses a planned, structured transition of its R&D leadership while emphasizing continuity of key clinical programs.

The company reports that Head of Research and Development Dr. Elizabeth H.Z. Thompson will retire for personal reasons but continue in her role during a transitional period and later as a consultant through at least the end of 2026. This staged approach is designed to preserve institutional knowledge around Acadia’s pipeline.

The disclosure specifically highlights remlifanserin, with Dr. Thompson expected to remain engaged through the planned Phase 2 readout in Alzheimer’s disease psychosis and into early Phase 3 execution. All ongoing trials, including Phase 2 studies in Alzheimer’s disease psychosis and Lewy Body Dementia Psychosis, are said to remain on track and blinded, with outcomes not yet known to the company or Dr. Thompson.

The impact of this change will depend on Acadia’s ability to recruit an experienced successor and maintain development timelines. Future company filings and clinical milestone updates will show how smoothly the leadership transition proceeds and whether clinical progress continues as described.

8-K Event Classification

3 items: 5.02, 7.01, 9.01

3 items

Item 5.02 Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers Governance

Key personnel changes including departures, elections, or appointments of directors and executive officers.

Item 7.01 Regulation FD Disclosure Disclosure

Material non-public information disclosed under Regulation Fair Disclosure, often investor presentations or guidance.

Item 9.01 Financial Statements and Exhibits Exhibits

Financial statements, pro forma financial information, and exhibit attachments filed with this report.

Key Figures

Retirement announcement date: April 30, 2026 Consulting period end: End of 2026 Phase 2 program stage: Phase 2 +2 more

5 metrics

Retirement announcement date April 30, 2026 Press release and 8-K disclosure date

Consulting period end End of 2026 Planned duration of Dr. Thompson’s consulting role

Phase 2 program stage Phase 2 Clinical stage for remlifanserin in Alzheimer’s disease psychosis

Remlifanserin LBDP stage Phase 2 Clinical stage for remlifanserin in Lewy Body Dementia Psychosis

Head of R&D tenure start 2024 Year Dr. Thompson joined as Head of Research and Development

Key Terms

Phase 2 clinical study, Alzheimer’s disease psychosis, Lewy Body Dementia Psychosis, Regulation FD Disclosure, +2 more

6 terms

Phase 2 clinical study medical

"through the planned readout of the Phase 2 clinical study of remlifanserin in Alzheimer’s disease psychosis"

A phase 2 clinical study is a mid-stage human test that checks whether a new drug or medical treatment works for the intended condition and further evaluates safety and dosing in a larger but still limited group of patients. For investors, phase 2 results are a key signal: positive findings make it more likely the treatment will progress toward larger, definitive trials and regulatory approval, while negative results can sharply reduce a drug’s commercial prospects, much like a prototype failing vital real-world tests.

Alzheimer’s disease psychosis medical

"Phase 2 clinical study of remlifanserin in Alzheimer’s disease psychosis (ADP)"

A set of hallucinations, false beliefs or related behavioral disturbances that occur in some people with Alzheimer’s disease, making memory loss and confusion worse and often increasing caregiving needs. It matters to investors because these symptoms represent a clear unmet medical need that drives clinical trials, regulatory review and potential drug sales; a treatment that safely reduces psychosis can change patient care patterns, lower long‑term costs and create significant market value, like fixing a major complication that suddenly makes a chronic problem much harder to manage.

Lewy Body Dementia Psychosis medical

"Phase 2 studies of remlifanserin in ADP and Lewy Body Dementia Psychosis (LBDP)"

Lewy body dementia psychosis is the set of hallucinations, false beliefs and severe confusion that can occur in people with Lewy body dementia, a progressive brain disorder marked by abnormal protein clumps in nerve cells. It matters to investors because these behavioral symptoms shape the need for treatments, influence clinical trial design and regulatory approval, and drive long‑term care costs and market size—like a key product feature that determines demand and safety scrutiny.

Regulation FD Disclosure regulatory

"Item 7.01 Regulation FD Disclosure."

Regulation FD disclosure requires public companies to share important, market-moving information with everyone at the same time instead of tipping off analysts or large investors first. Think of it as making sure all players on a field hear the same announcement simultaneously; that fairness helps investors trust that stock prices reflect the same information and reduces the risk of sudden, unfair trading advantages or regulatory penalties for selective leaks.

forward-looking statements regulatory

"This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995."

Forward-looking statements are predictions or plans that companies share about what they expect to happen in the future, like estimating sales or profits. They matter because they help investors understand a company's outlook, but since they are based on guesses and assumptions, they can sometimes be wrong.

Private Securities Litigation Reform Act of 1995 regulatory

"within the meaning of the Private Securities Litigation Reform Act of 1995."

Understanding 8-K Material Events →

false000107049400010704942026-04-272026-04-27

UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
WASHINGTON, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): April 27, 2026

Acadia Pharmaceuticals Inc.

(Exact name of Registrant as Specified in Its Charter)

Delaware			000-50768	06-1376651
(State or Other Jurisdiction of Incorporation)			(Commission File Number)	(IRS Employer Identification No.)
12830 El Camino Real, Suite 400
San Diego, California				92130
(Address of Principal Executive Offices)				(Zip Code)

Registrant’s Telephone Number, Including Area Code: (858) 558-2871

N/A

(Former Name or Former Address, if Changed Since Last Report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

	☐	Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)
	☐	Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)
	☐	Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))
	☐	Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

Title of each class		Trading Symbol(s)		Name of each exchange on which registered
Common Stock, par value $0.0001 per share		ACAD		The Nasdaq Stock Market LLC

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§ 230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§ 240.12b-2 of this chapter).

Emerging growth company ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Item 5.02 Departure Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers.

On April 27, 2026, Elizabeth H.Z. Thompson, Ph.D., Head of Research and Development, informed Acadia Pharmaceuticals Inc. (the “Company”) of her planned retirement. Dr. Thompson has decided to retire for personal reasons. She has committed to continuing in her role as Head of Research and Development for a transitional period until a successor is appointed, after which she intends to remain with the Company as a consultant through the end of 2026, including through the planned readout of the Company’s Phase 2 clinical study of remlifanserin in Alzheimer’s disease psychosis. The Company has initiated a search for Dr. Thompson’s replacement.

Item 7.01 Regulation FD Disclosure.

On April 30, 2026, the Company issued a press release announcing the planned retirement of Dr. Thompson. A copy of the press release is furnished as Exhibit 99.1 to this Current Report on Form 8-K.

As provided in General Instruction B.2 of Form 8-K, the information in this Item 7.01, including Exhibit 99.1 hereto, shall not be deemed to be “filed” for purposes of, or otherwise subject to the liabilities under, Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), nor shall such information or Exhibit 99.1 be deemed to be incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act, whether made before or after the date hereof, regardless of any general incorporation language in such filing, except as shall be expressly set forth by specific reference in such a filing.

Forward-Looking Statements

This Current Report on Form 8-K (this “Current Report”) contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. Words such as “will,” “continue,” “intends” and similar expressions (as well as other words or expressions referencing future events, conditions or circumstances) are intended to identify forward-looking statements. These forward-looking statements are based on the Company’s expectations and assumptions as of the date of this Current Report. Each of these forward-looking statements involves risks and uncertainties. Actual results may differ materially from these forward-looking statements. Forward-looking statements contained in this Current Report include, but are not limited to, statements regarding Dr. Thompson’s anticipated retirement from the Company, her continuing to serve in her current role during a transitional period and as a consultant once a successor is appointed, and the Company’s search for a replacement Head of Research and Development. Many factors may cause differences between current expectations and actual results, including the potential for Dr. Thompson to continue serving at the Company. Other factors that may cause actual results to differ from those expressed or implied in the forward-looking statements in this Current Report are discussed in the Company’s filings with the Securities and Exchange Commission, including its Annual Report on Form 10-K, Quarterly Reports on Form 10-Q and Current Reports on Form 8-K. Except as required by law, the Company assumes no obligation to update any forward-looking statements contained herein to reflect any change in expectations, even as new information becomes available.

Item 9.01 Financial Statements and Exhibits.

(d) Exhibits.

Exhibit Number		Description
99.1		Press Release dated April 30, 2026.
104		Cover Page Interactive Data File (embedded within the Inline XBRL document).

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

			Acadia Pharmaceuticals Inc.
Date:	April 30, 2026	By:	/s/ Jennifer J. Rhodes
			Jennifer J. Rhodes Executive Vice President, Chief Legal Officer

Exhibit 99.1

Acadia Pharmaceuticals Announces Planned Year-End Retirement of Elizabeth H.Z. Thompson, Ph.D., Head of Research and Development, Following a Distinguished Career

SAN DIEGO, Calif., April 30, 2026 — Acadia Pharmaceuticals Inc. (Nasdaq: ACAD) today announced the planned retirement of Elizabeth H.Z. Thompson, Ph.D., Head of Research and Development. Dr. Thompson has decided to retire for personal reasons and informed Acadia of her plans. She will continue in her role as Head of Research and Development until a successor is appointed. After her retirement, Acadia plans to retain Dr. Thompson as a consultant through at least the end of 2026 to ensure scientific and leadership continuity through the planned readout of the Phase 2 clinical study of remlifanserin in Alzheimer’s disease psychosis (ADP) and into early Phase 3 clinical study execution.

Acadia has initiated a search for a new Head of Research and Development and is committed to identifying an experienced R&D leader who will build on the strong scientific foundation already in place. The Company continues to advance its clinical development programs as planned. All ongoing clinical trials, including the Phase 2 studies of remlifanserin in ADP and Lewy Body Dementia Psychosis (LBDP), continue to recruit and remain blinded, and the Company, including Dr. Thompson, does not yet know study outcomes.

“Liz’s leadership has been instrumental in strengthening Acadia’s research and development organization, both scientifically and operationally, and in advancing a clear, disciplined R&D strategy across our pipeline,” said Catherine Owen Adams, Chief Executive Officer of Acadia. “She has been a strong advocate for the patients we serve and at every step has ensured thoughtful execution and prioritization of our programs in neurological and rare diseases. Just as importantly, Liz fostered a culture of clarity, accountability, and engagement across R&D. We are grateful for her continued commitment to Acadia during the transition period and for her willingness to remain engaged as a consultant, providing continuity of scientific leadership and institutional perspective in support of our mission and, most importantly, the patients we serve.”

“Leading Acadia’s research and development organization has been a defining chapter in my career and one in which I take a great deal of pride,” said Dr. Thompson. “We started from a great foundation, and have been able to build and strengthen the Acadia R&D team as well as make good progress in shaping and advancing a curated pipeline. I am particularly pleased with how we’ve been able to strengthen the remlifanserin program, especially by expanding it into Lewy Body Dementia Psychosis. I remain excited by the potential for remlifanserin and confident in the disciplined development strategy the Acadia team is executing. Beyond remlifanserin, our pipeline contains multiple programs that could represent truly meaningful options for patients living with neurological and rare diseases. While I have decided to retire for personal reasons, I am committed to continuing to lead the organization until the appointment of a successor and to supporting Acadia through the transition and the remainder of the year.”

Dr. Thompson joined Acadia in 2024 serving as Head of Research and Development. During her tenure, she helped strengthen the Company’s scientific and clinical capabilities, advance multiple development programs, and foster a culture of collaboration across research, clinical development and regulatory teams.

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.

Forward-Looking Statements

This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. Forward-looking statements include all statements other than statements of historical fact and can be identified by terms such as “may,” “will,” “should,” “expects,” “anticipates,” “continues,” “intends,” “planned,” and similar expressions (including the negative thereof) intended to identify forward-looking statements. Forward-looking statements contained in this press release, include, but are not limited to, statements about: (i) Dr. Thompson’s planned retirement, and her continued service in her role through a transitional period and as a consultant with the Company, (ii) our ability to recruit and timely hire a new Head of Research and Development, and (iii) the advancement of the Company’s clinical development programs, including the timely achievement of anticipated clinical milestones. Forward-looking statements are subject to known and unknown risks, uncertainties, assumptions and other factors that may cause our actual results, performance or achievements to differ materially and adversely from those anticipated or implied by our forward-looking statements. Such risks, uncertainties, assumptions and other factors include, but are not limited to Dr. Thompson’s continued services to the Company, future executive recruitment and the advancement of clinical development programs. Given the risks and uncertainties, you should not place undue reliance on these forward-looking statements. For a discussion of these and other risks, uncertainties, assumptions and other factors that may cause our actual results, performance or achievements to differ, please refer to our annual report on Form 10-K for the year ended December 31, 2025 filed with the Securities and Exchange Commission on February 26, 2026, as well as our subsequent filings with the Securities and Exchange Commission from time to time. The forward-looking statements contained herein are made as of the date hereof, and we undertake no obligation to update them after this date, except as required by law.

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

FAQ

What leadership change did Acadia Pharmaceuticals (ACAD) announce?

Acadia announced the planned retirement of Elizabeth H.Z. Thompson, Ph.D., its Head of Research and Development. She will stay through a transition period, then serve as a consultant through at least the end of 2026 to support ongoing R&D programs.

Why is Acadia’s Head of Research and Development retiring?

Elizabeth H.Z. Thompson, Ph.D., is retiring from Acadia for personal reasons. The company notes she informed them of her plans, will continue during a transitional period, and then remain as a consultant to help maintain continuity in research and development.

How long will Dr. Thompson remain involved with Acadia Pharmaceuticals (ACAD)?

Dr. Thompson will continue as Head of Research and Development until a successor is appointed, then serve as a consultant through at least the end of 2026. This covers the planned Phase 2 remlifanserin readout and early Phase 3 clinical execution.

What happens to Acadia’s remlifanserin clinical programs after this leadership change?

Acadia states all ongoing trials, including Phase 2 studies of remlifanserin in Alzheimer’s disease psychosis and Lewy Body Dementia Psychosis, continue to recruit and remain blinded. Dr. Thompson will support these programs through consulting after her retirement.

Is Acadia Pharmaceuticals (ACAD) searching for a new Head of Research and Development?

Yes. Acadia has initiated a search for a new Head of Research and Development. The company says it is committed to finding an experienced R&D leader to build on its existing scientific foundation and advance its clinical development pipeline.

Does Acadia link Dr. Thompson’s role to specific clinical milestones?

Yes. Acadia highlights that Dr. Thompson will help ensure continuity through the planned readout of the Phase 2 clinical study of remlifanserin in Alzheimer’s disease psychosis and into early Phase 3 execution, supporting stability around these key milestones.

Filing Exhibits & Attachments

2 documents

Press Releases

• EX-99.1 EX-99.1 13.5 KB

Other Documents

• EX-101 XBRL TAXONOMY EXTENSION SCHEMA WITH EMBEDDED LINKBASES DOCUMENT 25.6 KB