CAMBRIDGE, Mass., July 11, 2013 (GLOBE NEWSWIRE) -- Merrimack Pharmaceuticals, Inc. (Nasdaq:MACK) today announced that it has priced concurrent public offerings of 5,000,000 shares of its common stock at a price to the public of $5.00 per share and $125,000,000 aggregate principal amount of its 4.50% convertible senior notes due 2020 (the "Notes"), in each case, offered pursuant to Merrimack's effective Registration Statement on Form S-3 (File No. 333-186369) (the "Registration Statement") and a related prospectus filed with the Securities and Exchange Commission (the "SEC"). Merrimack has granted to the underwriters in the common stock offering an option, exercisable for 30 days, to purchase up to an additional 750,000 shares of its common stock and granted to the underwriters in the Notes offering an option, exercisable for 30 days, to purchase up to an additional $18,750,000 in aggregate principal amount of Notes. Merrimack expects to use the net proceeds from both offerings to complete the clinical development of, seek marketing approval for and fund pre-approval commercial efforts for MM-398 for the treatment of patients with metastatic pancreatic cancer whose cancer has progressed on treatment with the chemotherapy drug gemcitabine, to partially fund the clinical development of other clinical stage product candidates (including MM-398 for indications other than pancreatic cancer), to fund pre-clinical and research and development efforts and for other general corporate purposes. The Notes will bear interest at a rate of 4.50% per year, payable semiannually on January 15 and July 15 of each year, beginning January 15, 2014. The Notes will mature on July 15, 2020. The Notes will be convertible, under certain circumstances and during certain periods, at the option of the holder, based on an initial conversion rate of 160.0000 shares of common stock per $1,000 principal amount of Notes, which is equivalent to an initial conversion price of $6.25 per share of common stock, subject to adjustment in certain circumstances. The initial conversion price represents a conversion premium of 25% over the public offering price in the common stock offering. Following certain corporate events that occur prior to the maturity date, Merrimack will increase the conversion rate for a holder who elects to convert its Notes in connection with such a corporate event in certain circumstances. Upon any conversion of the Notes that occurs while Merrimack's indebtedness to Hercules Technology Growth Capital, Inc. ("Hercules"), under the Loan and Security Agreement dated November 8, 2012 between Merrimack and Hercules, remains outstanding, the Notes will be settled in shares of Merrimack's common stock. Following the repayment and satisfaction in full of Merrimack's obligations to Hercules under the Loan and Security Agreement, upon any conversion of the Notes the Notes may be settled, at Merrimack's election, in cash, shares of Merrimack's common stock or a combination of cash and shares of Merrimack's common stock.