================================================================================ UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 ------------------------------------ FORM 8-K Current Report Filed Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): May 21, 1999 ARONEX PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 0-20111 76-0196535 (State or other jurisdiction of (Commission File Number) (I.R.S. Employer Identification No.) incorporation or organization) 8707 Technology Forest Place The Woodlands, Texas 77381-1191 (Address of principal executive offices and zip code) (281) 367-1666 (Registrant's telephone number, including area code) ------------------------------------ ================================================================================ ITEM 5. OTHER EVENTS On May 21, 1999, Aronex Pharmaceuticals, Inc. (the "Company") entered into an Amendment No. 4 to License and Development Agreement with Genzyme Corporation ("Genzyme") to convert a $2.5 million payment into a three-year convertible note bearing interest at 10% annum. The $2.5 million payment obligation to Genzyme was triggered on March 29, 1999 when the Company regained the worldwide commercial rights of ATRAGEN(R), an injectable formulation of all-trans-retinoic acid (ATRA or tretinoin), from Genzyme. In connection with the Amendment, the Company entered into a 10% Convertible Note payable to Genzyme for $2.5 million. Genzyme has the right to convert the principal of the Note into shares of common stock of the Company at a conversion price of $4.35. Additionally, Genzyme was given a Common Stock Purchase Warrant entitling it to purchase 50,000 shares of the Company's common stock at an exercise price of $4.00 per share over a five-year term. ITEM 7. EXHIBITS Exhibit 10.1 -- Amendment No. 4 to License and Development Agreement dated May 21, 1999 by and between Aronex Pharmaceuticals, Inc. and Genzyme Corporation. Exhibit 10.2 -- 10% Convertible Note dated May 21, 1999 by Aronex Pharmaceuticals, Inc. made payable to Genzyme Corporation for $2.5 million. Exhibit 10.3 -- Common Stock Purchase Warrant for 50,000 shares of Common Stock of Aronex Pharmaceuticals, Inc. issued in the name of Genzyme Corporation. -2- SIGNATURES 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. ARONEX PHARMACEUTICALS, INC. Date: May 27, 1998 By: /s/ Terance A. Murnane ------------------------- Ternace A. Murnane Controller and Secretary -3-