SCHEDULE 13D/A

Under the Securities Exchange Act of 1934

(Amendment No. 3)*

Satsuma Pharmaceuticals, Inc.

(Name of Issuer)

Common Stock, par value $0.0001 per share

(Title of Class of Securities)

80405P107

(CUSIP Number)

RA Capital Management, L.P.

200 Berkeley Street, 18^th Floor

Boston, MA 02116

Telephone: 617.778.2512

Attn: Peter Kolchinsky

(Name, Address and Telephone Number of Person Authorized to

Receive Notices and Communications)

June 8, 2023

(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 §§240.13d-1(e), 240.13d-1(f) or 240.13d-1(g), check the following box. ¨

Note: Schedules filed in paper format shall include a signed original and five copies of the schedule, including all exhibits. See Rule 13d-7 for other parties to whom copies are to be sent.

* 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 (“Act”) or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

CUSIP No. 80405P107

CUSIP No. 80405P107

CUSIP No. 80405P107

CUSIP No. 80405P107

CUSIP No. 80405P107

SCHEDULE 13D

Item 1. Security and Issuer

Item 1 of the Statement is amended and supplemented as follows:

This Amendment No. 3 (this “Amendment No. 3” or this “13D/A”) amends and supplements the statement on the Schedule 13D originally filed with the Securities and Exchange Commission (the “SEC”) on September 17, 2019, and amended on March 2, 2021 and April 18, 2023 (as amended, the “Statement”), filed by RA Capital Management, L.P., Dr. Kolchinsky, Mr. Shah, and RA Capital Healthcare Fund, L.P. with respect to the common stock, par value $0.0001 per share (the “Common Stock”), of Satsuma Pharmaceuticals, Inc., a Delaware corporation (the “Issuer”). Unless otherwise defined herein, capitalized terms used in this Amendment No. 3 shall have the meanings ascribed to them in the Statement. Unless amended or supplemented below, the information in the Statement remains unchanged.

Item 4. Purpose of Transaction

Item 4 of the Statement is hereby amended and supplemented as follows:

Pursuant to the Offer to Purchase, dated May 5, 2023, from SNBL23 Merger Sub, Inc., a Delaware corporation (“Purchaser") and a wholly owned subsidiary of Shin Nippon Biomedical Laboratories, Ltd., to purchase all the outstanding shares of Common Stock (the “Offer”), on June 8, 2023, the Reporting Persons tendered all of the shares of Common Stock beneficially owned by them as previously reported on the Statement and such shares were accepted by the Purchaser on June 8, 2023.

Item 5. Interest in Securities of the Issuer

Item 5 of the Statement is amended and supplemented as follows:

(e) The Reporting Persons ceased to be beneficial owners of 5% or more of the Issuer’s Common Stock on June 8, 2023

Item 7. Material to Be Filed as Exhibits

Item 7 of the Statement is hereby amended and supplemented as follows:

CUSIP No. 80405P107

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Date:      June 12, 2023

CUSIP No. 80405P107

EXHIBIT 1

JOINT FILING AGREEMENT

This Joint Filing Agreement, dated as of June 12, 2023, is by and among RA Capital Management, L.P., Peter Kolchinsky, Rajeev Shah, and RA Capital Healthcare Fund, L.P. (the foregoing are collectively referred to herein as the “Filers”).

Each of the Filers may be required to file with the United States Securities and Exchange Commission a statement on Schedule 13G and/or 13D with respect to Common Stock, par value $0.0001 per share of Satsuma Pharmaceuticals, Inc. beneficially owned by them from time to time.

Pursuant to and in accordance with Rule 13(d)(1)(k) promulgated under the Securities Exchange Act of 1934, as amended, the Filers hereby agree to file a single statement on Schedule 13G and/or 13D (and any amendments thereto) on behalf of each of such parties, and hereby further agree to file this Joint Filing Agreement as an exhibit to such statement, as required by such rule.

This Joint Filing Agreement may be terminated by any of the Filers upon one week’s prior written notice or such lesser period of notice as the Filers may mutually agree.

Executed and delivered as of the date first above written.