Encysive Pharmaceuticals Inc - Statement of Beneficial Ownership (SC 13D)

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

SCHEDULE 13D
UNDER THE SECURITIES EXCHANGE ACT OF 1934

ENCYSIVE PHARMACEUTICALS INC.

(Name of Issuer)

Common Stock, par value $0.005 per share

(Title of class of securities)

29256X107

(CUSIP number)

Margaret M. Foran, Esq.
Pfizer Inc.
235 East 42nd Street
New York, NY 10017
Phone (212) 573-2323

with a copy to:

Raymond O. Gietz, Esq.
Weil, Gotshal & Manges LLP
767 Fifth Avenue
New York, New York 10153

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

April 1, 2008

(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 which 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
[_].

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CUSIP No. 226406106 13D Page 2
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1. NAME OF REPORTING PERSON: PFIZER INC.

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2. CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP:
 (a)[X]
 (b)[_]
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3. SEC USE ONLY

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4. SOURCE OF FUNDS: WC

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5. CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM
 2(d) OR 2(e): [_]
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6. CITIZENSHIP OR PLACE OF ORGANIZATION: Delaware

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 7. SOLE VOTING POWER: 67,688,555
 (See Item 5)
NUMBER OF --------------------------------------------------------------
SHARES 8. SHARED VOTING POWER: -0-
BENEFICIALLY
OWNED BY --------------------------------------------------------------
EACH 9. SOLE DISPOSITIVE POWER: 67,688,555
REPORTING (See Item 5)
PERSON WITH --------------------------------------------------------------
 10. SHARED DISPOSITIVE POWER: -0-

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11. AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON: 67,688,555
 (See Item 5)
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12. CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES:
 [_]
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13. PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11): 83.61%
 (See Item 5)
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14. TYPE OF REPORTING PERSON: CO

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CUSIP No. 226406106 13D Page 3
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1. NAME OF REPORTING PERSON: EXPLORER ACQUISITION CORP.

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2. CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP:
 (a)[X]
 (b)[_]
--------------------------------------------------------------------------------
3. SEC USE ONLY

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4. SOURCE OF FUNDS: AF

--------------------------------------------------------------------------------
5. CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM
 2(d) OR 2(e): [_]
--------------------------------------------------------------------------------
6. CITIZENSHIP OR PLACE OF ORGANIZATION: Delaware

--------------------------------------------------------------------------------
 7. SOLE VOTING POWER: 67,688,555
 (See Item 5)
NUMBER OF --------------------------------------------------------------
SHARES 8. SHARED VOTING POWER: -0-
BENEFICIALLY
OWNED BY --------------------------------------------------------------
EACH 9. SOLE DISPOSITIVE POWER: 67,688,555
REPORTING (See Item 5)
PERSON WITH --------------------------------------------------------------
 10. SHARED DISPOSITIVE POWER: -0-

--------------------------------------------------------------------------------
11. AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON: 67,688,555
 (See Item 5)
--------------------------------------------------------------------------------
12. CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES:
 [_]
--------------------------------------------------------------------------------
13. PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11): 83.61%
 (See Item 5)
--------------------------------------------------------------------------------
14. TYPE OF REPORTING PERSON: CO

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This statement on Schedule 13D is filed by Pfizer Inc. ("Pfizer"), and its wholly-owned subsidiary, Explorer Acquisition Corp. ("Explorer" or the "Purchaser"), and relates to the common stock, including the associated preferred stock purchase rights ("Common Stock"), $0.005 par value per share, of Encysive Pharmaceuticals Inc., a Delaware corporation ("Encysive" or the "Company").

ITEM 1. SECURITY AND ISSUER.

The title and class of equity securities to which this statement on Schedule 13D relates is the Common Stock of the Company. The Company's principal executive offices are located at 4848 Loop Central Drive, Suite 700 Houston, Texas 77081.

ITEM 2. IDENTITY AND BACKGROUND.

(a) - (c) and (f) This statement on Schedule 13D is being filed by Pfizer, a Delaware corporation, and Explorer, a Delaware corporation. Pfizer and Explorer are sometimes herein referred to collectively as the "Reporting Persons," and each as a "Reporting Person." The principal executive offices of Pfizer and Explorer are located at 235 East 42nd Street, New York, NY 10017. Pfizer is a research-based, global pharmaceutical company. Explorer was formed by Pfizer to acquire Encysive and has not conducted any unrelated activities since its organization.

Set forth on Schedule I to this statement on Schedule 13D and incorporated herein by reference is the following information with respect to each director and executive officer of Pfizer and Explorer:

(1) name;

(2) business address;

(3) principal occupation or employment and the name, principal business and address of any corporation or other organization in which such employment is conducted; and

(4) citizenship

(d) - (e) During the past five years, neither of the Reporting Persons nor, to the best knowledge of the Reporting Persons, any of the directors and executive officers of the Reporting Persons, (1) has been convicted in a criminal proceeding (excluding traffic violations and similar misdemeanors) or
(2) was a party to a civil proceeding of a judicial or administrative body of competent jurisdiction and as a result of such proceeding were or are subject to a judgment, decree or final order enjoining future violations of, or prohibited or mandating activities subject to, U.S. federal and state securities laws or finding any violations with respect to such laws.

ITEM 3. SOURCE AND AMOUNT OF FUNDS OR OTHER CONSIDERATION.

The information set forth in Section 9 entitled "Source and Amount of Funds" of the Offer to Purchase (as defined in Item 4) is incorporated herein by reference.

ITEM 4. PURPOSE OF TRANSACTION.

(a) - (j) The Reporting Persons and Encysive entered into an Agreement

and Plan of Merger, dated February 20, 2008 (the "Merger Agreement"), for the purposes of the Reporting Persons' acquisition of all of the issued and outstanding shares of Common Stock (the "Shares"). Pursuant to the Merger Agreement, Pfizer and Explorer commenced a tender offer (the "Offer") to purchase all of the outstanding Shares at a purchase price of $2.35 per Share, net to the seller in cash, without interest and less any required withholding taxes, upon the terms and subject to the conditions set forth in the Offer to Purchase, dated March 4, 2008 (the "Offer to Purchase"), incorporated by reference from Exhibit (a)(1)(A) of the Tender Offer Statement on Schedule TO filed by Explorer and Pfizer with the Securities and Exchange Commission (the "Commission") on March 4, 2008 (as amended, the "Schedule TO"), and the related Letter of Transmittal, incorporated by reference from Exhibit (a)(1)(B) of the Schedule TO. After consummation of the Offer, the Merger Agreement provides that Explorer will be merged (the "Merger") with and into Encysive, with Encysive surviving the Merger as a wholly-owned subsidiary of Pfizer. Each Share outstanding immediately prior to the effective time of the Merger (other than Shares held by Encysive, Pfizer or their wholly-owned subsidiaries, all of which will be cancelled and retired and shall cease to exist, or by stockholders who exercise appraisal rights under Delaware law), will be converted in the Merger into the right to receive $2.35 per Share, without interest and less any required withholding taxes.

The information set forth in the sections of the Offer to Purchase entitled "Summary Term Sheet," "Introduction," "Price Range of Shares; Dividends," "Certain Effects of the Offer," "Background of the Offer; Past Contacts or Negotiations," "Purpose of the Offer; Plans for Encysive," "The Merger Agreement" and "Dividends and Distributions" is incorporated herein by reference.

Except as set forth in this statement (including any information incorporated by reference) and in connection with the transaction described above, none of the Reporting Persons has any plan or proposal that related to or would result in any of the transactions described in subparagraphs (a) through
(j) of Item 4 to the Schedule 13D.

ITEM 5. INTERESTS IN THE SECURITIES OF THE PURCHASER.

(a) and (b) As a result of purchases of Shares pursuant to the Offer, on April 11, 2008, Pfizer and Explorer beneficially own an aggregate 67,688,555 shares (the "Shares") of Common Stock, representing 83.61% of the outstanding shares of Common Stock (based upon 80,955,060 Shares issued and outstanding as of March 28, 2008, as reported to the Reporting Persons by Encysive). Pfizer and Explorer each have sole voting and dispositive power of all the Shares by virtue of the fact that Explorer, the record holder of the Shares, is a wholly-owned subsidiary of Pfizer.

(c) On April 1, 2008, Explorer accepted 61,765,295 Shares for purchase, representing the number of Shares properly tendered and not withdrawn as of the initial expiration date for the Offer (excluding Shares subject to notices of guaranteed delivery). Pursuant to the subsequent offering period that is scheduled to expire on April 14, 2008 at 5:00 p.m., New York City time, as well as Shares delivered pursuant to notices of guaranteed delivery, Explorer purchased the following number of Shares on the following dates at the offer price of $2.35 per Share:

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DATE: NUMBER OF SHARES:
-----------------------------------------------------
April 1, 2008 166,666
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April 2, 2008 914,512
-----------------------------------------------------

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April 3, 2008 1,809,663
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April 4, 2008 576,170
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April 7, 2008 2,203,420
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April 8, 2008 29,407
-----------------------------------------------------
April 9, 2008 12,628
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April 10, 2008 210,794
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(d) Except as set forth in this Schedule 13D, none of the Reporting Parties has the right to receive or the power to direct the receipt of dividends from, or the proceeds of the sale of, securities covered by the Schedule 13D.

(e) Not applicable.

ITEM 6. CONTRACTS, ARRANGEMENTS, UNDERSTANDINGS OR RELATIONSHIPS WITH
RESPECT TO SECURITIES OF THE ISSUER.

The information provided in Item 4 of this Schedule 13D is incorporated herein by reference.

ITEM 7. MATERIAL TO BE FILED AS EXHIBITS.

Exhibit No. Description
----------- -----------
Exhibit 1 Agreement and Plan of Merger dated as of February
 20, 2008 among Encysive Pharmaceuticals Inc.,
 Pfizer Inc. and Explorer Acquisition Corp.
 (incorporated herein by reference to Exhibit
 (d)(1) to the Schedule TO filed by Pfizer Inc.
 with the Securities and Exchange Commission on
 March 4, 2008, as amended).

Exhibit 2 Offer to Purchase dated as of March 4, 2008
 (incorporated herein by reference to Exhibit
 (a)(1)(A) to the Schedule TO filed by Pfizer Inc.
 with the Securities and Exchange Commission on
 March 4, 2008, as amended).

Exhibit 3 Form of Letter of Transmittal dated as of March
 4, 2008 (incorporated herein by reference to
 Exhibit (a)(1)(B) to the Schedule TO filed by
 Pfizer Inc. with the Securities and Exchange
 Commission on March 4, 2008, as amended).

SIGNATURES

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.

Dated: April 11, 2008

PFIZER INC.

By: /s/ David Reid
 -------------------------------
Name: David Reid
Title: Assistant Secretary

EXPLORER ACQUISITION CORP.

By: /s/ Lawrence Miller
 -------------------------------
Name: Lawrence R. Miller
Title: Vice President

SCHEDULE I
DIRECTORS AND EXECUTIVE OFFICERS OF EXPLORER AND PFIZER

1. DIRECTORS AND EXECUTIVE OFFICERS OF EXPLORER.

The name, business address, present principal occupation or employment and material occupations, positions, offices or employment for the past five years of each of the directors and executive officers of Explorer are set forth below. The business address and phone number of each such director and executive officer is c/o Pfizer Inc., 235 East 42nd Street, New York, New York 10017,
(212) 733-2323. Unless otherwise noted, all directors and executive officers listed below are citizens of the United States.

NAME AND POSITION PRESENT PRINCIPAL OCCUPATION OR EMPLOYMENT

David Reid Senior Vice President and Managing Director,
Director Pfizer Inc.'s Legal Division. Mr. Reid has
 lead the Licensing, Mergers and Acquisitions
 and Antitrust Center of Excellence in Pfizer's
 Legal Division since 2003 and oversees a number
 of other functions. Mr. Reid is currently
 serving as Pfizer's Interim General Counsel.
 Prior to joining Pfizer in 1997, he was a
 partner at the law firm of Allen & Overy.

Douglas E. Giordano Vice President, Worldwide Business Development,
President Pfizer Inc. since April 2007; Vice President,
 US Planning and Business Development, Pfizer
 Inc., July 2005-March 2007; Senior
 Director/Team Leader, US Planning and Business
 Development, Pfizer Inc., January 2003-June
 2005; Director/Team Leader, US Planning and
 Business Development, Pfizer Inc., January
 2000-December 2002.

Lawrence R. Miller Assistant General Counsel, Licensing and
Director Business Development, Pfizer Inc., since June
Vice President 2006; Vice President and General Counsel, Enzon
 Pharmaceuticals, Inc., July 2005- May 2006;
 Senior Corporate Counsel, Pfizer Inc., November
 2002-July 2005; Corporate Counsel, Pfizer Inc.,
 October 2000-November 2002.

Joanne Smith-Farrell Senior Director, Business Development, Pfizer
Vice President Inc. since September 2007; Senior Vice
 President, Business Development and Licensing,
 Gene Logic Inc., February 2007-August 2007;
 Vice President, Corporate Development and
 Strategy, Gene Logic Inc., December
 2004-February 2007; Senior Director, Strategic
 Marketing, Gene Logic Inc., November
 2003-December 2004; President and CEO, emGene,
 Inc., August 2001-November 2003.

Susan Glimcher Tax Counsel, Pfizer Inc., since October 2001.
Vice President

NAME AND POSITION PRESENT PRINCIPAL OCCUPATION OR EMPLOYMENT

Susan Grant Senior Manager-Corporate Governance, Pfizer
Secretary Inc. since April 2006. Assistant Secretary of
 Pfizer since April 2003. Employed by Pfizer
 since June 2000 in various positions of
 increasing responsibility within the Corporate
 Governance group.

Kathleen R. O'Connell Director, International Treasury, Pfizer Inc
Vice President since 1995; Director, Cash Management, Pfizer
Treasurer Inc 1993-1995; Manager & Senior Manager,
 International Treasury, Pfizer Inc. 1988-1993;
 Senior Auditor, Pfizer Inc, 1986-1988.

2. DIRECTORS AND EXECUTIVE OFFICERS OF PFIZER

The name, business address, present principal occupation or employment and material occupations, positions, offices or employment for the past five years of each of the directors and executive officers of Pfizer are set forth below. The business address and phone number of each such director and executive officer is Pfizer Inc., 235 East 42nd Street, New York, New York 10017, (212) 733-2323. All directors and executive officers listed below are citizens of the United States.