1 SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(D) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report (Date of earliest event reported): November 3, 1998 TSENG LABS, INC. (Exact Name of Registrant Specified in Charter) Utah 0-13502 87-0391229 (State or Other (Commission File (I.R.S. Employer Jurisdiction of Number) Identification No.) Incorporation) 18 W. Airy Street Norristown, Pennsylvania 19401 (Address of Principal Executive Offices) (Zip Code) Registrant's telephone number, including area code: (610) 313-9388 (Former Name or Former Address, if Changed Since Last Report) 2 ITEM 5. OTHER EVENTS. On November 3, 1998, the Registrant consummated the transactions contemplated by the Agreement and Plan of Reorganization with Cell Pathways, Inc., a Delaware corporation, dated June 23, 1998 (the "Agreement"). For more details regarding this transaction, please refer to the press release dated November 3, 1998, which has been filed as Exhibit 99.1 hereto and is incorporated by reference herein. ITEM 7. FINANCIAL STATEMENTS, PRO FORMA FINANCIAL INFORMATION AND EXHIBITS (c) Exhibits Exhibit Number Description - -------------- ----------- 99.1 Press Release issued by the Registrant on November 3, 1998 announcing the consummation of the transaction with Cell Pathways, Inc. 3 SIGNATURE Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized. TSENG LABS, INC. (Registrant) By /s/ Mark H. Karsch Mark H. Karsch Senior Vice President and Chief Financial Officer Dated: November 3, 1998