EX-4 7 w2530280.txt LETTER AGREEMENT Exhibit 4 --------- NEUROGEN CORPORATION 35 Northeast Industrial Road Branford, Connecticut 06405 April 16, 2004 Warburg Pincus Private Equity VIII, L.P. 466 Lexington Avenue New York, NY 10017 Attention: Mr. Stewart Hen Andrew H. Tisch 2004 Annuity Trust #1 Daniel R. Tisch 2004 Annuity Trust #1 James S. Tisch 2004 Annuity Trust #1 Thomas J. Tisch 2004 Annuity Trust #1 667 Madison Avenue New York, NY 10021 Attention: Mr. Barry L. Bloom Andrew H. Tisch 2004 Annuity Trust II Daniel R. Tisch 2004 Annuity Trust II James S. Tisch 2004 Annuity Trust II Thomas J. Tisch 2004 Annuity Trust II 667 Madison Avenue New York, NY 10021 Attention: Mr. Barry L. Bloom Baker Bros. Investments, L.P. Baker Bros. Investments II, L.P. Baker Biotech Fund I, L.P. Baker Biotech Fund II, L.P. Baker/Tisch Investments, L.P. Baker Biotech Fund II (Z), L.P. 667 Madison Avenue, 17th Floor New York, NY 10021 Attention: Mr. Leo Kirby Gentlemen: Reference is made to the Securities Purchase Agreement, dated as of March 19, 2004 (the "SPA"), and amended as of March 26, 2004 by a Side Letter Agreement (the "Letter Agreement"), by and among Neurogen Corporation (the "Company") and the investors listed on the signature pages thereto (collectively, the "Investors"). It is hereby agreed that Investors Andrew H. Tisch 2004 Annuity Trust #1, Daniel R. Tisch 2004 Annuity Trust #1, James S. Tisch 2004 Annuity Trust #1 and Thomas J. Tisch 2004 Annuity Trust #1 are deleted from the SPA and the Letter Agreement and replaced with Andrew H. Tisch 2004 Annuity Trust II, Daniel R. Tisch 2004 Annuity Trust II, James S. Tisch 2004 Annuity Trust II and Thomas J. Tisch 2004 Annuity Trust II, respectively, effective as of the respective dates of execution thereof. Accordingly, each of Andrew H. Tisch 2004 Annuity Trust II, Daniel R. Tisch 2004 Annuity Trust II, James S. Tisch 2004 Annuity Trust II and Thomas J. Tisch 2004 Annuity Trust II will purchase 267,858 shares of Common Stock at $7.00 per share. This letter agreement may be executed in one or more counterparts (including by facsimile), which shall be deemed an original and all of which together shall be considered one and the same agreement. If you are in agreement with the matters set forth above, please sign this letter in the space indicated below and return to the undersigned. Very truly yours, NEUROGEN CORPORATION By: /s/ Steve Davis ------------------------------ Name: Steve Davis Title: EVP & CBO ACCEPTED AND AGREED: WARBURG PINCUS PRIVATE EQUITY VIII, L.P. By: Warburg Pincus & Co., General Partner By: /s/ Stewart Hen ------------------------------ Name: Stewart Hen Title: Partner -2- BAKER/TISCH INVESTMENTS, L.P. By: Baker/Tisch Capital, L.P., General Partner By: Baker/Tisch Capital (GP), LLC, General Partner By: /s/ Felix Baker, Ph.D. ------------------------------ Name: Felix Baker, Ph.D. Title: Managing Member BAKER BROS. INVESTMENTS, L.P. By: Baker Bros. Capital, L.P., General Partner By: Baker Bros. Capital (GP), LLC, General Partner By: /s/ Felix Baker, Ph.D. ------------------------------ Name: Felix Baker, Ph.D. Title: Managing Member BAKER BROS. INVESTMENTS II, L.P. By: Baker Bros. Capital, L.P., General Partner By: Baker Bros. Capital (GP), LLC, General Partner By: /s/ Felix Baker, Ph.D. ------------------------------ Name: Felix Baker, Ph.D. Title: Managing Member BAKER BIOTECH FUND I, L.P. By: Baker Biotech Capital, L.P., General Partner By: Baker Biotech Capital (GP), LLC, General Partner By: /s/ Felix Baker, Ph.D. ------------------------------ Name: Felix Baker, Ph.D. Title: Managing Member -3- BAKER BIOTECH FUND II, L.P. By: Baker Biotech Capital II, L.P., General Partner By: Baker Biotech Capital II (GP), LLC, General Partner By: /s/ Felix Baker, Ph.D. ------------------------------ Name: Felix Baker, Ph.D. Title: Managing Member BAKER BIOTECH FUND II (Z), L.P. By: Baker Biotech Capital II, L.P., General Partner By: Baker Biotech Capital II (GP), LLC, General Partner By: /s/ Felix Baker, Ph.D. ------------------------------ Name: Felix Baker, Ph.D. Title: Managing Member ANDREW H. TISCH 2004 ANNUITY TRUST #1 DANIEL R. TISCH 2004 ANNUITY TRUST #1 JAMES S. TISCH 2004 ANNUITY TRUST #1 THOMAS J. TISCH 2004 ANNUITY TRUST #1 ANDREW H. TISCH 2004 ANNUITY TRUST II DANIEL R. TISCH 2004 ANNUITY TRUST II JAMES S. TISCH 2004 ANNUITY TRUST II THOMAS J. TISCH 2004 ANNUITY TRUST II /s/ Barry L. Bloom ------------------------------ Name: Barry L. Bloom Title: Attorney-in-Fact cc: Milbank, Tweed, Hadley & McCloy LLP 1 Chase Manhattan Plaza New York, NY 10005 Attention: Robert B. Williams, Esq. Willkie Farr & Gallagher LLP 787 Seventh Avenue New York, NY 10019 Attention: Steven J. Gartner, Esq. -4- Sullivan & Cromwell 125 Broad Street New York, NY 10004 Attention: Richard R. Howe, Esq.