Filed Pursuant to Rule 424(b)(7)

Filed Pursuant to Rule 424(b)(7)

File No. 333-130591

PROSPECTUS SUPPLEMENT NO. 4

TO PROSPECTUS DATED DECEMBER 21, 2005 (as supplemented by Prospectus Supplement No. 1 dated January 18, 2006, Prospectus Supplement No. 2 dated January 19, 2006 and Prospectus Supplement No. 3 dated February 14, 2006)

NEKTAR THERAPEUTICS

$315,000,000 of 3.25% Convertible Subordinated Notes Due 2012

and Shares of Common Stock Issuable Upon Conversion of the Notes

 

This prospectus supplement supplements the prospectus, dated December 21, 2005, relating to the resale by selling securityholders of our 3.25% convertible subordinated notes due 2012 and shares of our common stock into which the notes are convertible. This prospectus supplement should be read in conjunction with the prospectus, and is qualified by reference to the prospectus, except to the extent that the information presented herein supersedes the information contained in the prospectus. This prospectus supplement is not complete without, and may not be delivered or utilized except in connection with, the prospectus, including any amendments or supplements thereto.

Investing in our notes or our common stock offered by this prospectus involves a high degree of risk. Please carefully consider the “Risk Factors” beginning on page 5 of the prospectus as well as the section entitled “Risk Factors” included in our most recent annual report on Form 10-K and in our most recent quarterly report on Form 10-Q, as well as any amendments thereto, as filed with the Securities and Exchange Commission.

 

NEITHER THE SECURITIES AND EXCHANGE COMMISSION NOR ANY STATE SECURITIES COMMISSION HAS APPROVED OR DISAPPROVED OF THESE SECURITIES OR DETERMINED IF THIS PROSPECTUS SUPPLEMENT OR THE PROSPECTUS TO WHICH IT RELATES IS TRUTHFUL OR COMPLETE. ANY REPRESENTATION TO THE CONTRARY IS A CRIMINAL OFFENSE.

 

The information in the table appearing under the caption “Selling Securityholders” in the prospectus is amended by adding the information below with respect to persons not previously listed in the prospectus or in any amendments or supplements thereto, and by superseding the information with respect to persons previously listed in the prospectus with the information that is set forth below:

 

Name

    Principal Amount
of Notes Beneficially
Owned and Offered (1)		    Common
Stock
Beneficially
Owned (1)(2)		    Common
Stock
Offered (1)(2)		   

Principal Amount

of Notes Owned After
Completion of Offering

   

Common Stock

Beneficially Owned After

Completion of the Offering (3)

               Number of
Shares		    Percentage
Ownership

Daimler Chrysler Corp Emp #1 Pension Plan, dtd 4/1/89

    $ 2,417,000    112,324    112,324    —      —      *

Empyrean Capital Fund, L.P.

    $ 3,846,500    178,757    178,757    —      —      *

Empyrean Capital Overseas Fund, Ltd.

    $ 6,416,200    298,178    298,178    —      —      *

Empyrean Capital Overseas Benefit Plan Fund, Ltd.

    $ 737,300    34,264    34,264    —      —      *

FPL Group Employee Pension Plan

    $ 485,000    22,539    22,539    —      —      *

Franklin and Marshall College

    $ 60,000    2,788    2,788    —      —      *

LDG Limited

    $ 109,000    5,065    5,065    —      —      *

Radcliffe SPC, Ltd for and on behalf of the Class A Convertible Crossover Segregated Portfolio

    $ 0    0    0    —      —      *

Rampart Enhanced Convertible Investors, LLC

    $ 550,000    25,559    25,559    —      —      *

MSS Convertible Arbitrage I c/o TQA Investors

    $ 30,000    1,394    1,394    —      —      *

TQA Master Plus Fund

    $ 401,000    18,635    18,635    —      —      *

TQA Master Fund

    $ 1,115,000    51,817    51,817    —      —      *

Sphinx Fund c/o TQA Investors

    $ 109,000    5,065    5,065    —      —      *

Zurich Institutional Benchmark Master Fund c/o TQA Investors

    $ 236,000    10,967    10,967    —      —      *
* Less than one percent.
(1) Amounts indicated may be in excess of the total amount registered due to sales or transfers exempt from the registration requirements of the Securities Act since the date upon which the selling holders provided to us the information regarding their notes and common stock.
(2) Unless otherwise noted, represents shares of common stock issuable upon conversion of the Notes.
(3) Percentage is based on 87,684,184 shares of common stock outstanding as of December 13, 2005.

The date of this prospectus supplement is March 28, 2006.