Ipsen to Acquire Oncology Assets from Merrimack Pharmaceuticals

• Transaction includes U.S. commercialization rights for ONIVYDE® for
metastatic pancreatic cancer in adult patients1
• $575 million cash at closing and additional
potential payments for new indications
• Transaction bolsters Ipsen’s growing oncology presence and leverages
Oncology infrastructure in the U.S.

Paris (France), 9 January 2017 – Ipsen (Euronext: IPN; ADR: IPSEY) today announced that it
has entered into a definitive agreement to acquire global oncology assets from Merrimack
Pharmaceuticals (NASDAQ: MACK), including its key marketed product ONIVYDE® (irinotecan
liposome injection) for the treatment of patients with metastatic adenocarcinoma of the pancreas
after disease progression following gemcitabine-based therapy, in combination with fluorouracil
and leucovorin. Under the terms of the agreement, Ipsen will gain exclusive commercialization
rights for the current and potential future ONIVYDE indications in the U.S., as well as the current
licensing agreements with Shire for commercialization rights ex-U.S. and PharmaEngine for
Taiwan. The transaction also includes Merrimack’s commercial and manufacturing infrastructure,
and generic doxorubicin HCl liposome injection.

The transaction represents a unique opportunity and a strong strategic fit for Ipsen. ONIVYDE is
a clinically differentiated and FDA-approved product for patients with high unmet medical needs.
The transaction secures a marketed, wholly-owned asset with current U.S. revenues and
significant revenue growth projections, based on solid clinical data and potential approvals in
additional indications already in clinical development. Furthermore, there are significant
commercial synergies to be realized by integrating the ONIVYDE franchise with the existing
Ipsen U.S. oncology commercial infrastructure, which has strong expertise and a proven track
record with Somatuline®. As a result, this transaction strengthens Ipsen’s Oncology franchise
and accelerates both its near- and long-term growth trajectory and profitability.

David Meek, CEO of Ipsen, commented, “The acquisition of ONIVYDE represents a compelling
strategic opportunity to further strengthen Ipsen’s oncology portfolio while leveraging our U.S.
infrastructure and creating meaningful potential incremental growth and profitability. Pancreatic
cancer is now the third leading cause of cancer-related deaths. It is an area that has had many
drug failures and very few FDA approvals over the past two decades. For the tens of thousands
of patients living with pancreatic cancer in the U.S. who have received prior treatment with gemcitabine, ONIVYDE represents an important, differentiated innovation, given its proven
overall survival benefit in an area of high unmet medical need with few approved therapies.”

“ONIVYDE is a landmark, recently approved therapeutic option for metastatic pancreatic cancer.
Since the launch in the fourth quarter of 2015, many patients have already benefitted from
ONIVYDE.” said
Cynthia Schwalm, Executive Vice President, North America Commercial
Operations, Ipsen. “Based on our track record of successfully bringing oncology products to
patients, we are confident in our ability to leverage our operational and clinical development
capabilities, and experienced commercial and medical affairs teams to ensure eligible patients
have access to ONIVYDE in the U.S.”

Ipsen will be responsible for advancing the ongoing ONIVYDE clinical development program,
which includes a Phase 2 trial in first-line previously untreated metastatic pancreatic cancer, a
Phase 2/3 trial in relapsed small-cell lung cancer, and a Phase 1 pilot trial in breast cancer.

Under the terms of the agreement, Ipsen will pay $575 million cash at closing plus up to $450
million upon the approval of potential additional indications for ONIVYDE in the U.S. The
transaction will be fully financed by Ipsen’s existing cash and lines of credit. The deal should be
dilutive in 2017 and accretive from 2018 onwards both in operating margin and EPS. The
transaction, which is subject to customary closing conditions, including governmental regulatory
clearances, and a vote by Merrimack shareholders, is expected to close by the end of the first
quarter of 2017.

Ipsen was advised on this transaction by MTS Health Partners, LP and Dechert LLP.

Conference Call
Ipsen will host a conference call and web conference (available at www.ipsen.com) today to
discuss this announcement. Participants should dial in approximately 5 to 10 minutes prior to the
start. No reservation is required to participate in the conference call.
Date: 9 January, 2017
Time: 2:30pm CET/ 8:30am EST
France and continental Europe +33 (0)1 7099 3208
UK +44 (0)20 7162 0077
United States +1 646 851 2407
Conference ID: 961094
A replay will be available for seven days on Ipsen’s website: www.ipsen.com/
France and continental Europe +33 (0)1 7099 3529
UK +44 (0)20 7031 4064
United States +1 954 334 0342
Conference ID: 961094
About Pancreatic Cancer
Pancreatic cancer is a rare and deadly disease with approximately 338,000 new patients diagnosed globally each year, approximately 50,000 of which are in the United States2. More than half are diagnosed with metastatic disease who have an overall 5-year survival rate of two
percent2,and often rapidly progress during or shortly after receiving chemotherapy3. Pancreatic cancer is the 3rd leading cause of cancer-related death in the United States surpassing breast
cancer.2 It is expected to become the 2nd leading cause of cancer-related death in the US by
the year 2030, surpassing colorectal cancer.2
ONIVYDE® is a unique encapsulation formulation of irinotecan in a long-circulating liposomal
form designed to increase the length of tumor exposure to irinotecan and its active metabolite
SN-38. In the pivotal Phase 3 NAPOLI-1 study, ONIVYDE with fluorouracil and folinic acid demonstrated a statistically significant improvement of overall survival in adult patients with metastatic
adenocarcinoma of the pancreas who have progressed following gemcitabine-based
therapy3. Gemcitabine, both as monotherapy as well as in combination, is commonly used in the
first-line treatment of locally advanced and/or metastatic pancreatic adenocarcinoma, as well as
in the adjuvant (treatment after surgery) and neo-adjuvant (treatment before surgery) settings4.

Ipsen will market the product in the United States where ONIVYDE received US Food and Drug
Administration (FDA) approval in October 2015 in combination with fluorouracil and leucovorin
for the treatment of patients with metastatic adenocarcinoma of the pancreas who have
progressed following treatment with gemcitabine-based therapy.
Shire is responsible for the development and commercialization of ONIVYDE outside of the
United States and Taiwan under an exclusive licensing agreement with Merrimack
Pharmaceuticals, Inc. In October 2016, the European Commission (EC) granted Marketing
Authorization of ONIVYDE for the treatment of metastatic adenocarcinoma of the pancreas, in
combination with 5-fluorouracil (5-FU) and leucovorin (LV), in adult patients who have
progressed following gemcitabine-based therapy.
The ONIVYDE product license was granted to PharmaEngine in March 2016 for
commercialization rights in Taiwan.
Licenses outside the U.S. will be transferred to Ipsen.
About Generic Doxorubicin HCl Liposome Injection
Generic doxorubicin HCl Liposome Injection is currently being evaluated by the U.S. Food and
Drug Administration (FDA) for the potential treatment of ovarian cancer, multiple myeloma and
Kaposi’s sarcoma. Teva retains the worldwide commercial rights for this product, and Ipsen will
be eligible to receive milestones and shared profits from potential sales.
About Ipsen in North America
Ipsen Biopharmaceuticals, Inc. is the US affiliate of Ipsen, a global specialty driven
pharmaceutical group. The US head office is located in Basking Ridge, New Jersey. Ipsen Biopharmaceuticals Canada, Inc. is an integrated business unit within North America and has its
head office located in Mississauga, Ontario. Ipsen Bioscience, Inc., the Ipsen US research and
development center focused on peptide research in oncology and endocrinology, is located in
Cambridge, Massachusetts. At Ipsen Bioscience, we focus on creating a highly cooperative and
passionate R&D organization through partnerships, innovation, and continuous learning to
effectively deliver new treatments for patients. At Ipsen Biopharmaceuticals, we focus our
resources, investments, and energy on discovering, developing, and commercializing new
therapeutic options for oncologic, neurologic, and endocrine diseases. For more information on
Ipsen in North America, please visit www.ipsenus.com or www.ipsen.ca.
About Ipsen in Oncology
Ipsen focuses its efforts in fighting cancers such as prostate cancer or those with high unmet
medical needs such as bladder cancer, neuroendocrine tumors, kidney cancer, pancreatic
cancer and other niche oncology diseases. Our ambition is to offer new therapeutic options to
patients and caregivers in their treatment journeys. Ipsen has a continuous commitment in
innovative treatment development in oncology through an open innovation approach and using
differentiated technological platforms notably in peptides. Moreover Ipsen has built scientific
partnerships with trusted academic institutions, leading pharmaceutical and biotech companies
and work with today’s top researchers and clinicians. We thus develop effective and innovative
therapeutic solutions to improve treatment outcomes for patients and to support healthcare
professionals in their daily practice.
About Ipsen
Ipsen is a global specialty-driven pharmaceutical group with total sales exceeding €1.4 billion in
2015. Ipsen sells more than 20 drugs in more than 115 countries, with a direct commercial
presence in more than 30 countries. Ipsen’s ambition is to become a leader in specialty
healthcare solutions for targeted debilitating diseases. Its fields of expertise cover oncology,
neurosciences and endocrinology (adult & pediatric). Ipsen’s commitment to oncology is
exemplified through its growing portfolio of key therapies improving the care of patients suffering
from neuro-endocrine tumors, prostate cancer, bladder cancer and renal cancer. Ipsen also has
a significant presence in primary care. Moreover, the Group has an active policy of partnerships.
Ipsen’s R&D is focused on its innovative and differentiated technological platforms, peptides and
toxins, located in the heart of the leading biotechnological and life sciences hubs
(Les Ulis/ParisSaclay, France; Slough/Oxford, UK; Cambridge, US). In 2015, R&D
expenditures neared €193 million. The Group has more than 4,600 employees worldwide.
Ipsen’s shares are traded on segment A of Euronext Paris (stock code: IPN, ISIN code:
FR0010259150) and are eligible to the “Service de Règlement Différé” (“SRD”). The Group is
part of the SBF 120 index. Ipsen has implemented a Sponsored Level I American Depositary Receipt (ADR) program, which trades on the over-the-counter market in the United States under the symbol IPSEY. For more information on Ipsen, visit www.ipsen.com.
Ipsen Forward-looking Statements
The forward-looking statements, objectives and targets contained herein are based on the
Group’s management strategy, current views and assumptions. Such statements involve known
and unknown risks and uncertainties that may cause actual results, performance or events to
differ materially from those anticipated herein. All of the above risks could affect the Group’s
future ability to achieve its financial targets, which were set assuming reasonable
macroeconomic conditions based on the information available today. Use of the words “believes,” “anticipates” and “expects” and similar expressions are intended to identify forwardlooking statements, including the Group’s expectations regarding future events, including
regulatory filings and determinations. Moreover, the targets described in this document were
prepared without taking into account external growth assumptions and potential future
acquisitions, which may alter these parameters. These objectives are based on data and
assumptions regarded as reasonable by the Group. These targets depend on conditions or facts
likely to happen in the future, and not exclusively on historical data. Actual results may depart
significantly from these targets given the occurrence of certain risks and uncertainties, notably
the fact that a promising product in early development phase or clinical trial may end up never
being launched on the market or reaching its commercial targets, notably for regulatory or
competition reasons. The Group must face or might face competition from generic products that
might translate into a loss of market share. Furthermore, the Research and Development
process involves several stages each of which involves the substantial risk that the Group may
fail to achieve its objectives and be forced to abandon its efforts with regards to a product in
which it has invested significant sums. Therefore, the Group cannot be certain that favorable
results obtained during pre-clinical trials will be confirmed subsequently during clinical trials, or
that the results of clinical trials will be sufficient to demonstrate the safe and effective nature of
the product concerned. There can be no guarantees a product will receive the necessary
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assumptions prove inaccurate or risks or uncertainties materialize, actual results may differ
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include but are not limited to, general industry conditions and competition; general economic
factors, including interest rate and currency exchange rate fluctuations; the impact of
pharmaceutical industry regulation and health care legislation; global trends toward health care
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expected. Such situations could have a negative impact on the Group’s business, financial
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reflect any change in events, conditions, assumptions or circumstances on which any such
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Financiers. The risks and uncertainties set out are not exhaustive and the reader is advised to
refer to the Group’s 2015 Registration Document available on its website (www.ipsen.com).

For Further Information

Ipsen Media
Didier Véron
Senior Vice-President, Public Affairs
and Communication
Tel.: +33 (0)1 58 33 51 16
E-mail: didier.veron@ipsen.com

Brigitte Le Guennec
Corporate External Communication Manager
Tel.: +33 (0)1 58 33 51 17
E-mail : brigitte.le.guennec@ipsen.com

Financial Community
Eugenia Litz
Vice-President, Investor Relations
Tel.: +44 (0) 1753 627721
E-mail: eugenia.litz@ipsen.com

Côme de La Tour du Pin
Investor Relations Manager
Tel.: +33 (0)1 58 33 53 31
E-mail: come.de.la.tour.du.pin@ipsen.com

Ipsen Biopharmaceuticals, Inc. (North America)
Media Elliot Fox
W2O Group
Tel: 212.257.6724
Email: efox@w2ogroup.com

Dawn Sciortino
W2O Group
Tel: 646-380-3500
Email: dsciortino@w2ogroup.com

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