X0202 4 2008-04-11 0 0000849043 NEUROGEN CORP NRGN 0001157334 WARBURG PINCUS PRIVATE EQUITY VIII L P C/O WARBURG PINCUS LLC 466 LEXINGTON AVENUE NEW YORK NY 10017 0 0 1 0 0001322709 Warburg Pincus Partners LLC C/O WARBURG PINCUS LLC 466 LEXINGTON AVENUE NEW YORK NY 10017 0 0 1 0 0001162870 WARBURG PINCUS LLC C/O WARBURG PINCUS LLC 466 LEXINGTON AVENUE NEW YORK NY 10017 0 0 1 0 0000929408 WARBURG PINCUS & CO C/O WARBURG PINCUS LLC 466 LEXINGTON AVENUE NEW YORK NY 10017 0 0 1 0 0001220638 LANDY JOSEPH C/O WARBURG PINCUS LLC 466 LEXINGTON AVENUE NEW YORK NY 10017 0 0 1 0 0001239318 KAYE CHARLES R C/O WARBURG PINCUS LLC 466 LEXINGTON AVENUE NEW YORK NY 10017 0 0 1 0 Common Stock, par value $0.025 per share 8571429 D Series A Exchangeable Preferred Stock 2008-04-11 4 P 0 192307 A Common Stock 4999982 192307 D Warrant to purchase Common Stock 2.30 2008-04-11 4 P 0 192307 A 2013-04-11 Common Stock 2499991 192307 D See Exhibit 99.1 Exhibit List: Exhibit 99.1 - Explanation of Responses Exhibit 99.2 - Joint Filers' Names and Addresses Exhibit 99.3 - Joint Filers' Signatures WARBURG PINCUS PRIVATE EQUITY VIII, L.P. By: Warburg Pincus Partners, LLC, its General Partner By: Warburg Pincus & Co., its Managing Member By: /s/ Scott A. Arenare Name: Scott A. Arenare Title: Partner 2008-04-14