AS FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON APRIL 14, 2000 REGISTRATION STATEMENT NO. 333-90399 ================================================================================ SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 ------------------------------------ POST-EFFECTIVE AMENDMENT NO. 1 TO FORM S-3 ------------------------------------ REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933 ------------------------------------ MILLENNIUM PHARMACEUTICALS, INC. (EXACT NAME OF REGISTRANT AS SPECIFIED IN ITS CHARTER) ------------------------------------ DELAWARE 04-3177038 (STATE OR OTHER JURISDICTION OF (I.R.S. EMPLOYER INCORPORATION OR ORGANIZATION) IDENTIFICATION NUMBER) 75 SIDNEY STREET CAMBRIDGE, MASSACHUSETTS 02139 (ADDRESS, INCLUDING ZIP CODE, AND TELEPHONE NUMBER, INCLUDING AREA CODE, OF REGISTRANT'S PRINCIPAL EXECUTIVE OFFICES) ------------------------------------ MARK J. LEVIN CHIEF EXECUTIVE OFFICER MILLENNIUM PHARMACEUTICALS, INC. 75 SIDNEY STREET CAMBRIDGE, MASSACHUSETTS 02139 (617) 679-7000 (NAME, ADDRESS, INCLUDING ZIP CODE, AND TELEPHONE NUMBER, INCLUDING AREA CODE, OF AGENT FOR SERVICE) ------------------------------------ COPIES TO: DAVID E. REDLICK, ESQ. JOHN B. DOUGLAS III, ESQ. DAVID TRUMMEL, ESQ. HALE AND DORR LLP MILLENNIUM PHARMACEUTICALS, INC. ELI LILLY AND COMPANY 60 STATE STREET 75 SIDNEY STREET LILLY CORPORATE CENTER BOSTON, MASSACHUSETTS 02109 CAMBRIDGE, MASSACHUSETTS 02139 INDIANAPOLIS, INDIANA 46286 TELEPHONE: (617) 526-6000 TELEPHONE: (617) 679-7000 TELEPHONE: (317) 276-5669 EXPLANATORY NOTE Pursuant to a Registration Statement (the "Registration Statement") on Form S-3 (File No. 333-90399), Millennium Pharmaceuticals, Inc. (the "Registrant") registered shares of its common stock, $.001 par value per share ("Common Stock"), under the Securities Act of 1933, as amended. Pursuant to the Registrant's undertaking contained in the Registration Statement, this Post-Effective Amendment No. 1 to Registration Statement on Form S-3 is being filed solely to remove from registration the shares of Common Stock which remain unsold under such Registration Statement as of the date of this Post-Effective Amendment No. 1. SIGNATURES Pursuant to Rule 478 promulgated under the Securities Act of 1933, the Registrant certifies that it has reasonable grounds to believe that it meets the requirements for filing on Form S-3 and has duly caused this Post-Effective Amendment No. 1 to Registration Statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Cambridge, Commonwealth of Massachusetts, on this 14th day of April, 2000. MILLENNIUM PHARMACEUTICALS, INC. By: /S/ KEVIN STARR -------------------------------- KEVIN STARR Chief Financial Officer