13D Filing: Baker Bros. Advisors and Acadia Pharmaceuticals Inc (NASDAQ:ACAD)

 

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, DC 20549

 

SCHEDULE 13D

(Rule 13d-102)

 

INFORMATION TO BE INCLUDED IN STATEMENTS
FILED PURSUANT

TO RULE 13d-l(a) AND AMENDMENTS THERETO
FILED PURSUANT

TO RULE 13d-2(a)

(Amendment No. 12)*

ACADIA
Pharmaceuticals Inc.

(Name of Issuer)

Common Stock, par value $0.0001 per share

(Title of Class of
Securities)

004225108

(CUSIP number)

Alexandra A. Toohey

Chief Financial Officer

Baker Bros. Advisors LP

860 Washington Street, 3^rd Floor

New York, NY 10014

(212) 339-5690

(Name,
address and telephone number of person authorized to receive notices and communications)

September 20, 2018

(Date of event which requires filing of this statement)

If
the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule
13D, and is filing this schedule because of Rule 13d-1(e), 13d-1(f) or 13d-1(g), check the following box ¨.

(Continued on the following pages)

(Page 1 of 10 Pages)

________________________________

*The remainder of this cover page shall
be filled out for a reporting person’s initial filing on this form with respect to the subject class of securities, and for
any subsequent amendment containing information which would alter disclosures provided in a prior cover page.

The information required on the remainder of this cover page
shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of 1934 or otherwise
subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act.