U.S. FDA Grants Priority Review for MM-398 New Drug Application

PDUFA date set for October 24, 2015
Merrimack seeking U.S. marketing approval of MM-398 for the treatment of patients with metastatic pancreatic cancer who have been previously treated with gemcitabine-based therapy
European Medicines Agency accepts Baxalta's Marketing Authorization Application for review

CAMBRIDGE, Mass. and DEERFIELD, Ill., June 25, 2015-- Merrimack Pharmaceuticals, Inc. (MACK) and Baxalta Incorporated, a wholly-owned subsidiary of Baxter International Inc (BAX), today jointly announced that the New Drug Application (NDA) for MM-398 (irinotecan liposome injection), also known as "nal-IRI," has been accepted for review by the U.S. Food and Drug Administration (FDA).  Merrimack is seeking U.S. marketing approval of MM-398 for the treatment of patients with metastatic adenocarcinoma of the pancreas who have been previously treated with gemcitabine-based therapy.

In addition, the FDA has classified the NDA as having Priority Review status. A Priority Review designation is for drugs that treat serious conditions and, if approved, would provide significant improvements in the safety or effectiveness of the treatment of serious conditions compared to available therapies. The FDA has set a goal of October 24, 2015 to take action under the Prescription Drug User Fee Act (PDUFA).

"The rapid timeline associated with Priority Review designation brings Merrimack closer to our goal of making MM-398 available to patients with pancreatic cancer who have been previously treated with gemcitabine and are in significant need of treatment options," said Robert Mulroy, President and CEO at Merrimack. "We look forward to working with the FDA as they review the application over the next several months."

Merrimack's application is based upon the results of an international Phase 3 study (NAPOLI-1) conducted in patients with metastatic pancreatic cancer who previously received gemcitabine-based therapy. MM-398 in combination with 5-fluorouracil (5-FU) and leucovorin achieved its primary and secondary endpoints by demonstrating a statistically significant improvement in overall survival, progression free survival and overall response rate compared to the control group of patients who received a combination of 5-FU and leucovorin. The most common Grade 3 or higher adverse events in patients receiving MM-398 and 5-FU/LV were neutropenia, fatigue and gastrointestinal effects. This was the first global Phase 3 study in a post-gemcitabine setting to show a survival benefit in this aggressive disease.  Data for the study were presented at the European Society for Medical Oncology World Congress on Gastrointestinal Cancer (ESMO GI) in June 2014 and the American Society of Clinical Oncology 2015 Gastrointestinal Cancers Symposium (ASCO GI) in January 2015.   

The European Medicines Agency (EMA) has also accepted for review a Marketing Authorization Application (MAA) for MM-398 for the treatment of patients with metastatic adenocarcinoma of the pancreas who have been previously treated with gemcitabine-based therapy. The acceptance of the MAA marks the beginning of the review process in the European Union for MM-398 in this indication.

"The acceptance of our Marketing Authorization Application for review by the European Medicines Agency is a positive indicator of the promise of this treatment to address a significant unmet need for patients with metastatic pancreatic cancer and the support for innovative new options," said David Meek, head of Oncology at Baxalta. "We are actively advancing our plans to introduce nal-IRI following approval and look forward to extending the utility of the treatment to patients around the world."

The FDA and EMA have granted MM-398 orphan drug designation for patients with metastatic pancreatic cancer. MM-398 was granted Fast Track designation by the FDA in November 2014.

Merrimack and Baxalta have entered into an exclusive licensing agreement to develop and commercialize MM-398 outside of the United States.  PharmaEngine, Inc. (Taipei, Taiwan) holds the rights to commercialize MM-398 in Taiwan.

About MM-398

MM-398 (irinotecan liposome injection), also known as "nal-IRI," is a novel encapsulation of irinotecan in a long-circulating liposomal formulation. The activated form of irinotecan is SN-38, which functions by inhibiting topoisomerase I (an essential enzyme involved in DNA transcription and replication) and promoting cell death.

About Pancreatic Cancer ^1,2

Pancreatic cancer is rare and deadly, accounting for only three percent of all cancer cases worldwide but is the fourth leading cause of cancer death. An estimated 140,000 new cases are diagnosed every year around the world, two-thirds of which are among people aged 65 or older.

Because the signs and symptoms of pancreatic cancer are non-specific and may not appear until the disease has spread to other sites, approximately 80% of patients are diagnosed with late stage disease.  These patients are not candidates for surgery, instead receiving chemotherapy as the mainstay of their therapy. This contributes to the five year survival rate for all patients being less than six percent; fewer than 20 percent of newly diagnosed patients survive more than two years. There is no consensus on the standard of care for patients with metastatic pancreatic cancer previously treated with a gemcitabine-based therapy.

About Merrimack Pharmaceuticals

Merrimack is a biopharmaceutical company discovering, developing and preparing to commercialize innovative medicines paired with companion diagnostics for the treatment of cancer. Merrimack seeks to gain a deeper understanding of underlying cancer biology through its systems biology-based approach and develop new insights, therapeutics and diagnostics to improve outcomes for cancer patients. Merrimack has multiple oncology therapeutics in clinical development and additional candidates in late stage preclinical development. Merrimack has a New Drug Application under review for its lead product candidate, MM-398, for the treatment of patients with metastatic adenocarcinoma of the pancreas who have been previously treated with gemcitabine-based therapy. For more information, please visit Merrimack's website at www.merrimackpharma.com or connect on Twitter at @MerrimackPharma.

About Baxalta Incorporated

Baxalta Incorporated, a wholly-owned subsidiary of Baxter International Inc. (BAX), is a global biopharmaceutical company that develops, manufactures and commercializes therapies focused on hematology, oncology and immunology. Headquartered in Northern Illinois, Baxalta employs 16,000 employees worldwide and its Global Innovation and R&D Center is located in Cambridge, Massachusetts. Baxalta's therapies are available in more than 100 countries and it has biological manufacturing operations across 12 facilities, including recombinant production and plasma fractionation.

About Baxter International Inc.

Baxter International Inc., through its subsidiaries, develops, manufactures and markets products that save and sustain the lives of people with hemophilia, immune disorders, cancer, infectious diseases, kidney disease, trauma and other chronic and acute medical conditions. As a global, diversified healthcare company, Baxter applies a unique combination of expertise in medical devices, pharmaceuticals and biotechnology to create products that advance patient care worldwide.

Forward-Looking Statements

This release includes forward-looking statements concerning MM-398 and the related collaboration between Baxalta Incorporated and Merrimack Pharmaceuticals, Inc., including expectations with regard to clinical studies and related data, regulatory filings, plans regarding commercial launch and potential impact to patients. The statements are based on assumptions about many important factors, including the following, which could cause actual results to differ materially from those in the forward-looking statements: satisfaction of regulatory and other requirements; actions of regulatory bodies and other governmental authorities; additional clinical trial results; changes in laws and regulations; issues with product quality, manufacturing or supply; patient safety issues; and other risks identified in Baxter International Inc.'s and Merrimack's most recent filings on Form 10-K and other SEC filings as well as the Form 10 filed by Baxalta Incorporated. Neither Baxter nor Merrimack undertakes to update their forward-looking statements.

¹ American Cancer Society. Cancer Facts and Figures 2014. Atlanta: American Cancer Society; 2014. 
² World Health Organization. GLOBOCAN 2012: Estimated Cancer Incidence, Mortality and Prevalence Worldwide in 2012; Lyon, Fr.: International Agency for Research on Cancer; 2012.

CONTACT:
Merrimack Media Contact: 
Dana Robie  
617-441-7408 
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Merrimack Investor Contact: 
Geoffrey Grande, CFA 
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Baxter Media Contact: 
Kellie Hotz
224-948-5353

Baxter Investor Contact:
Mary Kay Ladone
224-948-3371