News Release
                    
                Mallinckrodt Pharmaceuticals Announces Completion of MNK-155 Clinical Trials
                
      MNK-155 studies evaluated pharmacokinetics, efficacy, safety and
      abuse liability
    
    ST. LOUIS--(BUSINESS WIRE)--Dec. 12, 2013--
      Mallinckrodt
      (NYSE: MNK) today reported positive efficacy results in the Phase 3
      clinical trial for MNK-155, an investigational extended-release oral
      formulation of hydrocodone and acetaminophen studied for the management
      of moderate to moderately severe acute pain where the use of an opioid
      analgesic is appropriate. MNK-155 met the primary endpoint in this study.
    
      Mallinckrodt also completed a series of other clinical trials evaluating
      pharmacokinetics, safety and abuse liability of MNK-155. These data,
      including the Phase 3 efficacy data, will be presented at a future
      medical meeting and will be submitted to the U.S. Food and Drug
      Administration (FDA) in a New Drug Application (NDA) for MNK-155. The
      NDA is expected to be submitted in the second half of fiscal 2014.
    
      “Despite the number of available pain medications, some patients
      continue to experience unresolved pain. Our goal is to provide another
      treatment option for the management of moderate to moderately severe
      acute pain for patients and their physicians,” said Mario Saltarelli,
      Chief Science Officer, Mallinckrodt. “We are encouraged by these
      findings and look forward to submitting these results to the FDA as part
      of our application.”
    
      The Phase 3 efficacy study evaluated the efficacy and safety of MNK-155
      in a post-surgical acute pain model. The primary endpoint was the summed
      pain intensity difference (change in pain from baseline) over 48 hours
      (SPID48) compared to placebo. The most common adverse events
      associated with the use of MNK-155 were nausea (25%), vomiting,
      dizziness, headache, constipation and somnolence (sleepiness).
    
      About Mallinckrodt
    
      Mallinckrodt is a global specialty pharmaceutical business that
      develops, manufactures, markets and distributes specialty pharmaceutical
      products and medical imaging agents. The company’s Specialty
      Pharmaceuticals segment includes branded and generic drugs and active
      pharmaceutical ingredients, and the Global Medical Imaging segment
      includes contrast media and nuclear imaging agents. Mallinckrodt has
      approximately 5,500 employees worldwide and commercial presence in
      roughly 70 countries. The company’s 2013 revenue totaled $2.2 billion.
      To learn more about Mallinckrodt, visit www.mallinckrodt.com.
    
      FORWARD-LOOKING STATEMENTS
    
      Any statements contained in this communication that do not describe
      historical facts may constitute forward-looking statements as that term
      is defined in the Private Securities Litigation Reform Act of 1995. Such
      forward-looking statements include, but are not limited to, statements
      about future financial condition and operating results, economic,
      business, competitive and/or regulatory factors affecting our business.
      Any forward-looking statements contained herein are based on our
      management's current beliefs and expectations, but are subject to a
      number of risks, uncertainties and changes in circumstances, which may
      cause actual results or Company actions to differ materially from what
      is expressed or implied by these statements. The factors that could
      cause actual future results to differ materially from current
      expectations include, but are not limited to, our ability to receive
      procurement and production quotas granted by the U.S. Drug Enforcement
      Administration, our ability to obtain and/or timely transport
      molybdenum-99 to our technetium-99m generator production facilities,
      customer concentration, cost-containment efforts of customers,
      purchasing groups, third-party payors and governmental organizations,
      our ability to successfully develop or commercialize new products, our
      ability to protect intellectual property rights, competition, our
      ability to integrate acquisitions of technology, products and
      businesses, product liability losses and other litigation liability, the
      reimbursement practices of a small number of large public or private
      issuers, complex reporting and payment obligation under healthcare
      rebate programs, changes in laws and regulations, conducting business
      internationally, foreign exchange rates, material health, safety and
      environmental liabilities, litigation and violations and information
      technology infrastructure. These and other factors are identified and
      described in more detail in the “Risk Factors” section of the Form 10
      Registration Statement, as amended. We disclaim any obligation to update
      these forward-looking statements other than as required by law.
    
    

Source: Mallinckrodt
      Mallinckrodt
Lynn Phillips, 314-654-3263
Manager, Media
      Relations
lynn.phillips@mallinckrodt.com
or
Meredith
      Fischer, 314-654-3318
Senior Vice President, Communications
meredith.fischer@mallinckrodt.com
or
John
      Moten, 314-654-6650
Vice President, Investor Relations
john.moten@mallinckrodt.com