UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

PURSUANT TO SECTION 13 OR 15(d) ~~OF THE~~

OF THE SECURITIES EXCHANGE ACT OF 1934

Date of report (Date of earliest event reported): November 13 18, 2025

PFIZER INC.

(Exact name of registrant as specified in its charter)

Delaware	1-3619	~~1-3619~~	13-5315170	~~13-5315170~~
(State or other		(Commission File		(I.R.S. Employer
(State or other jurisdictionof incorporation)	(Commission File Number)		(I.R.S. Employer Identification No.)
jurisdiction of		Number)		Identification No.)
incorporation)

66 Hudson Boulevard East			~~10001-2192~~
New York,		New York	(Zip Code)
New York, New York	10001-2192
(Address of principal executive offices)	(Zip Code)

(Address of principal executive offices)

Registrant’s telephone number, including area code:

(212) 733-2323

(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 (see General Instruction A.2. below):

☐ Written ~~communications~~communication 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, $0.05 par value

PFE

New York Stock Exchange

1.000% Notes due 2027

PFE/27

New York Stock Exchange

2.875% Notes due 2029

PFE/29

New York Stock Exchange

3.250% Notes due 2032

PFE/32

New York Stock Exchange

3.875% Notes due 2037

PFE/37A

New York Stock Exchange

4.250% Notes due 2045

PFE/45

New York Stock Exchange

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, $0.05 par value	PFE	New York Stock Exchange
1.000% Notes due 2027	PFE/27	New York Stock Exchange
2.875% Notes due 2029	PFE/29	New York Stock Exchange
3.250% Notes due 2032	PFE/32	New York Stock Exchange
3.875% Notes due 2037	PFE/37A	New York Stock Exchange
4.250% Notes due 2045	PFE/45	New York Stock Exchange

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 8.01 ~~Results of~~ Other Events.

On November 13 21, 2025, Pfizer Inc. (~~“Pfizer” or~~ the “Company”) completed ~~the~~a ~~previously~~public ~~announced~~offering ~~acquisition~~ of ~~Metsera~~$500, ~~Inc.~~000,000 aaggregate ~~Delaware~~principal ~~corporation~~amount ~~(“Metsera”),~~of ~~pursuant~~Floating toRate ~~the~~Notes ~~Agreement~~due ~~and~~2027 ~~Plan~~(the of“Floating ~~Merger,~~Rate ~~dated as of September 21~~Notes”), ~~2025~~$1,000,000,000 asaggregate ~~amended~~principal byamount ~~Amendment~~of No3.875% 1Notes todue 2027 (the ~~Agreement~~“2027 ~~and Plan of Merger~~Notes”), ~~dated as of November 7~~$1, ~~2025~~000,000,000 byaggregate ~~and~~principal ~~among~~amount ~~the~~of ~~Company,~~4.200% ~~Metsera~~Notes ~~and~~due ~~Mayfair~~2030 ~~Merger~~(the ~~Sub~~“2030 Notes”), ~~Inc.~~$1,250,000,000 aaggregate ~~Delaware~~principal ~~corporation~~amount ~~and wholly owned subsidiary~~ of ~~the~~4.500% ~~Company~~Notes ~~(as~~due ~~amended,~~2032 (the “~~Merger~~2032 ~~Agreement~~Notes”)~~. Pursuant~~, ~~to the Merger Agreement~~$1,250,000,000 ~~each~~aggregate ~~issued~~principal ~~and~~amount ~~outstanding share~~ of ~~Metsera~~4.875% ~~common~~Notes ~~stock~~due ~~(other~~2035 ~~than certain shares set forth in~~ (the ~~Merger~~“2035 ~~Agreement~~Notes”), ~~was converted into the right to receive~~ $~~65.60 in cash at closing~~500,000,000 ~~representing~~aggregate anprincipal ~~enterprise~~amount ~~value~~ of ~~approximately $7~~5.0600% ~~billion,~~Notes ~~and~~due ~~one~~2055 ~~non-transferable~~(the ~~contingent~~“2055 ~~value~~Notes”) ~~right~~and ~~entitling~~$500,000,000 ~~holders~~aggregate toprincipal ~~potential~~amount ~~additional payments~~ of ~~up to $20~~5.65700% ~~per~~Notes ~~share~~due in2065 ~~cash tied to~~ (the ~~achievement~~“2065 ofNotes” ~~three~~and, ~~specific~~together ~~milestones:~~with ~~(i)~~the ~~$4.60~~Floating ~~per~~Rate ~~share~~Notes, ~~payable upon~~ the ~~initiation~~2027 ofNotes, the ~~Phase~~2030 3Notes, ~~clinical~~the ~~trial~~2032 ~~start~~Notes, ofthe ~~Metsera’s~~2035 ~~injectable~~Notes ~~GLP-1~~and ~~receptor~~the ~~antagonist~~2055 ~~MET-097i+~~Notes, ~~amylin~~the ~~analog MET-233i combination; (ii) $6.40 per share payable upon U.S. Food and Drug Administration (~~“~~FDA~~Notes”) ~~approval of Metsera’s monthly MET-097i monotherapy; and (iii) $9~~.65 ~~per share payable upon FDA approval of Metsera’s monthly MET-097i+MET-233i combination.~~

~~SIGNATURES~~The offering of the Notes was made pursuant to the shelf registration statement on Form S-3 (Registration No. 333-277323) of the Company, Pfizer Investment Enterprises Pte. Ltd. and Pfizer Netherlands International Finance B.V., originally filed with the Securities and Exchange Commission (the “Commission”) on February 23, 2024, as amended by the Post-Effective Amendment No. 1 thereto, filed with the Commission on May 13, 2025.

~~Pursuant~~The Notes were issued pursuant to an indenture (the ~~requirements~~“Base Indenture”), dated as of September 7, 2018, between the ~~Securities~~Company ~~Exchange~~and ~~Act~~The Bank of ~~1934~~New York Mellon, as trustee (the ~~Registrant~~“Trustee”), ~~has~~as ~~duly~~supplemented ~~caused~~by ~~this~~the ~~report~~sixth tosupplemental beindenture ~~signed~~(the on“Sixth ~~its~~Supplemental ~~behalf~~Indenture” and, the Base Indenture as supplemented by the ~~undersigned~~Sixth ~~hereunto~~Supplemental ~~duly~~Indenture, ~~authorized~~the “Indenture”), dated as of November 21, 2025, between the Company and the Trustee.

	PFIZER INC.
Dated: November 13, 2025	By:	/s/ Margaret M. Madden
		Margaret M. Madden
		Senior Vice President and Corporate Secretary
		Chief Governance Counsel

The Sixth Supplemental Indenture is filed herewith as Exhibit 4.2 to this Current Report on Form 8-K and is incorporated herein by reference. Each of the form of Floating Rate Notes, the form of 2027 Notes, the form of 2030 Notes, the form of 2032 Notes, the form of 2035 Notes, the form of 2055 Notes and the form of 2065 Notes are filed herewith as Exhibit 4.3, Exhibit 4.4, Exhibit 4.5, Exhibit 4.6, Exhibit 4.7, Exhibit 4.8 and Exhibit 4.9 to this Current Report on Form 8-K, respectively, and are incorporated herein by reference.

In connection with the offering of the Notes, the Company entered into an underwriting agreement (the “Underwriting Agreement”) and related pricing agreement (the “Pricing Agreement”), each dated November 18, 2025, with Citigroup Global Markets Inc., Deutsche Bank Securities Inc., J.P. Morgan Securities LLC and Mizuho Securities USA LLC, as representatives of the several underwriters listed on Schedule I to the Pricing Agreement.

The Underwriting Agreement and the Pricing Agreement are filed herewith as Exhibit 1.1 and Exhibit 1.2 to this Current Report on Form 8-K, respectively, and are incorporated herein by reference.

In addition, in connection with the offering of the Notes, the Company is filing a legal opinion regarding the validity of the Notes, which is filed herewith as Exhibit 5.1 to this Current Report on Form 8-K.

Item 9.01

Financial Statements and Exhibits.

(d) Exhibits


Exhibit No.		Exhibit Description

1.1		Underwriting Agreement, dated November 18, 2025.

1.2		Pricing Agreement, dated November 18, 2025.

4.1		Indenture, dated as of September 7, 2018 (incorporated by reference from the Company’s Current Report on Form 8-K filed on September 7, 2018).

4.2		Sixth Supplemental Indenture, dated as of November 21, 2025, between Pfizer Inc. and The Bank of New York Mellon, as trustee.

4.3		Form of Floating Rate Notes due 2027 (included in Exhibit 4.2).

4.4		Form of 3.875% Notes due 2027 (included in Exhibit 4.2).

4.5		Form of 4.200% Notes due 2030 (included in Exhibit 4.2).

4.6		Form of 4.500% Notes due 2032 (included in Exhibit 4.2).

4.7		Form of 4.875% Notes due 2035 (included in Exhibit 4.2).

4.8		Form of 5.600% Notes due 2055 (included in Exhibit 4.2).

4.9		Form of 5.700% Notes due 2065 (included in Exhibit 4.2).

5.1		Opinion of Margaret M. Madden, Senior Vice President and Corporate Secretary, Chief Governance Counsel of the Company.

23.1		Consent of Margaret M. Madden, Senior Vice President and Corporate Secretary, Chief Governance Counsel of the Company (included in Exhibit 5.1).

104		Cover Page Interactive Data File (embedded within the Inline XBRL document).

SIGNATURE

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.


	PFIZER INC.

	By:	/s/ Margaret M. Madden
		Margaret M. Madden
		Senior Vice President and Corporate Secretary,
		Chief Governance Counsel

Dated: November 21, 2025

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