Mallinckrodt plc, a leading specialty biopharmaceutical company, and The Gores Group, a global investment firm, have entered into a definitive agreement under which a subsidiary of Mallinckrodt will acquire Therakos, Inc., a leading immunotherapy company, in a transaction valued at approximately $1.325 billion.

Subject to customary closing conditions, the parties expect the transaction to be completed in the latter part of the third calendar quarter of 2015, Mallinckrodt's fourth fiscal quarter.

Therakos, Inc. is the global leader in autologous immune cell therapy delivered through extracorporeal photopheresis (ECP), and is focused on providing innovative treatment platforms that harness the power of patients' immune systems to fight disease. Therakos photopheresis is approved by the US Food and Drug Administration for the palliative treatment of the skin manifestations of cutaneous T-cell lymphoma (CTCL) in persons who have not been responsive to other forms of treatment. Outside the US, Therakos photopheresis is also broadly approved for ECP, and used by physicians in countries around the world in immune-modulating applications in a variety of conditions including CTCL, graft versus host disease, Crohn's disease, solid organ transplants and other diseases.

Therakos therapeutic platforms, including the latest generation Therakos Cellex photopheresis system, are the world's only approved, fully integrated systems for administering autologous immune cell therapy through ECP. Used by academic medical centres, hospitals and treatment centres in more than 25 countries, Therakos systems have been used to deliver over one million photopheresis treatments globally.

"This transaction demonstrates our ongoing commitment to building a strong, highly profitable hospital growth business as we build and diversify Mallinckrodt's specialty brands portfolio," said Mark Trudeau, president and chief executive officer of Mallinckrodt.

"In expanding our hospital portfolio we continue to move decisively in line with our strategic roadmap. And we believe we will be able to unlock untapped value in Therakos – making ECP treatment accessible to more patients in more hospitals by applying some of the innovative contract, service and customer intimacy principles that have been so successful with our Inomax (nitric oxide) for inhalation. One of Mallinckrodt's core strengths is our unique ability to manage complexity, delivering additional value to diverse products and environments. With this expansion into immunotherapy we add to our footprint of nuclear medicine, pain management, and respiratory neonatal critical care, broadening our touch points in hospitals and further expanding our portfolio with innovative therapies."

Trudeau added, "Therakos is, quite simply, another excellent fit for Mallinckrodt. It is an immunotherapy treatment for patients who may have exhausted other therapies, with significant potential value in a variety of complex disease states and conditions. Installed in more than 350 academic medical centres and hospitals around the world, it is delivered in hospital-based out-patient clinics via an innovative, fully integrated, drug-device combination that is widely reimbursed globally. And it is supported by a high-touch, high-service commercial model that is very similar to and has a high degree of potential hospital account overlap with Inomax."

Alec Gores, chief executive officer and chairman of The Gores Group, stated "Following our acquisition of Therakos from Ortho-Clinical Diagnostics, Inc., a former subsidiary of Johnson & Johnson, in December 2012 , we took a number of steps to expand and grow the business, including appointing a healthcare leadership team, led by Michael Rechtiene and Sandra Thompson, with more than 20 years of experience in the space."

Gores continued, "We are proud of Therakos' success, especially its innovation and impact on patients globally, and believe it is a classic example of Gores' strength in acquiring corporate carve-outs and partnering with management teams to successfully transition corporate subsidiaries into thriving standalone businesses."

With this transaction, Mallinckrodt further broadens its specialty brands portfolio and diversifies its hospital offerings with an innovative, durable, high-value, high-margin drug-device system already used in hospitals and major medical centres in more than 25 countries around the world.

Therakos photopheresis platforms, including the latest generation Cellex system, are expected to significantly enhance and broaden Mallinckrodt's footprint in hospitals -- further extending the company's presence from multimodal surgical pain management and critical care respiratory therapies in neonatal intensive care units to include innovative therapies that harness the patient's own immune systems to fight disease and improve health.

Approved and marketed as an outpatient therapy delivered through an integrated drug-device combination, Cellex photopheresis systems will benefit from Mallinckrodt's larger hospital presence, regulatory expertise, long experience in complex drug and device manufacturing, and support of similar medication- technology-service offerings such as Inomax.

The Therakos commercial team will be integrated into Mallinckrodt's current critical care organisation within its hospital specialty brands business. The company expects to augment sales of Therakos products with its skilled customer experience teams, which include sales, marketing, training and clinician support.

Assuming a close in late fiscal 2015, the transaction is expected to be accretive by no less than $0.10 per share to Mallinckrodt's adjusted diluted fiscal 2016 earnings and increasingly accretive thereafter. With roughly 60 per cent of Therakos' revenue in the US, Mallinckrodt expect fiscal 2015 net sales of $185 to $195 million, and anticipate high single-digit growth off that base going forward, driven primarily by the US.

Mallinckrodt International Finance S.A. (MIFSA) has entered into debt financing commitments for amounts that, together with cash on hand, are expected to be sufficient to provide funds necessary to consummate the transaction. Completion of the transaction is subject to regulatory approvals and other customary conditions.