0001274792 2024-04-30 2024-04-30 MERRIMACK PHARMACEUTICALS INC false 0001274792 8-K 2024-04-30 DE 001-35409 04-3210530 One Broadway 14th Floor Cambridge MA 02142 (617) 720-8606 Class A common stock, $0.01 par value per share MACK NASDAQ false true false false false