PRESS RELEASE ELSALYS BIOTECH acquires from JAZZ PHARMACEUTICALS the worldwide rights of LEUKOTAC®, an immunotherapy antibody with clinical benefits in steroid- resistant acute Graft-versus-Host Disease • In a recent clinical study, it has shown a - favorable risk/benefit profile, supporting the experience already obtained with LEUKOTAC® in nearly 1,200 patients with acute graft-versus-host disease (aGvHD). • Developed to date by JAZZ PHARMACEUTICALS, LEUKOTAC® has received an orphan designation in Europe and the United States. • ELSALYS BIOTECH has initiated discussion with the European health authorities (EMA) and will engage in regulatory interactions with the FDA in 2018. Lyon, FRANCE, October 12, 2017, ELSALYS BIOTECH, a new player in immuno-oncology, has acquired from JAZZ PHARMACEUTICALS the development and commercialization rights of LEUKOTAC® (inolimomab), a monoclonal antibody that has recently demonstrated its clinical superiority in the treatment of Steroid-Resistant acute Graft-versus-Host Disease (steroid-resistant aGvHD), an orphan disease with very poor prognosis. GvHD is the main complication of hematopoietic stem cell transplantation, the last treatment option for patients with certain blood cancers and severe immunodeficiency. To date, clinicians have no reliable means to predict the occurrence of GvHD and even less its steroid-resistant form. No treatment has yet obtained marketing authorization in this indication and each year steroid-resistant aGvHD causes almost 4,000 deaths in Europe1. LEUKOTAC® (inolimomab) is an immunotherapy monoclonal antibody against the IL-2 receptor that blocks the action of T-cells responsible for aGvHD. It was already administrated to nearly 1,200 children and adults with aGvHD, mostly with steroid-resistant aGvHD, whether in clinical trials or for compassionate use. Based on additional analyses of a recent pivotal Phase 3 study conducted in 100 patients with severe with steroid-resistant aGvHD (77% of patients diagnosed grade 3 or 4), LEUKOTAC® has demonstrated very promising results both in terms of efficacy (37% reduction in the risk of death, p=0.055 1-sided and reduction of primary composite endpoint of death at one year without change in treatment 28%, p=0.095 1-sided) and tolerability (significant reduction in adverse events, in particular infectious). All these results were obtained in comparison with a control group receiving anti-thymoglobulin immunosuppressant. ELSALYS BIOTECH is now in discussion with the European Medicines Agency (EMA) in order to assess the terms of registration at the earliest opportunity. At the same time, to allow physicians and patients to gain access as quickly as possible to LEUKOTAC®, ELSALYS BIOTECH is currently preparing requests for compassionate use authorization of the drug for patients with severe steroid-resistant aGvHD with the different national health authorities (Named Patient Basis or cohort Temporary Authorization for Use2 evaluated in France by the 1 Center for International Blood and Marrow Transplant Research 2016 report. 2 Temporary Use Autorization cohort in France (ATUc), or compassionate use authorization in the other European countries, provides early access to medicinal products that have not been granted marketing authorization. ELB Leukotac PR 1 PRESS RELEASE ANSM, the National Agency for Medicines and health products Safety). Discussions with the US Food and Drug Administration (FDA) are expected to start as early as 2018. LEUKOTAC® could be the first product registered in Europe in this orphan indication in both adults and children “Nearly 50% of patients with aGvHD rapidly develop resistance to steroids, the reference first- line treatment, and to date clinicians have no approved standard treatment3 for patients for whom therapy is no longer an option” says Dr David LIENS, Chief Medical Officer, ELSALYS BIOTECH “The additional analyses from the recent Phase 3 trial conducted in the same patients shown that our novel antibody, that specifically blocks one of the main immune receptors implicated in aGvHD, could be the first product registered in Europe in this orphan indication in both adults and children.” “Above all, we are very proud to offer a first potential therapeutic option to transplant patients with steroid-resistant aGvHD. Today these patients are indeed victims of a “double punishment” since after having overcome a serious blood disorder with the help of bone marrow transplantation, they have another life-threatening disease, this time linked to the transplant” highlights Dr. Christine GUILLEN, CEO and Co-founder, ELSALYS BIOTECH “Clearly it is also a major step for our company as it validates our strategy based on validated innovative targets and niche markets on which our antibodies are able to make a difference. Consequently, five years after its creation, ELSALYS BIOTECH could be one of the first French biopharmaceutical companies to enter the main segment of the oncology market: immunotherapy.” About steroid-resistant aGvHD Formerly called bone marrow transplant, Hematopoietic Stem Cell Transplantation (HSCT) is the last therapeutic option for patients with certain blood cancers or severe immunodeficiency. In practice, the treatment is designed to replace the diseased blood cells of the patient with the hematopoietic stem cells of a matching donor (allograft). Once grafted, these stem cells will produce new healthy and functional blood cells, including white blood cells that will allow patients to bridge their immune deficiency or to eliminate surviving cancer cells. If this technique has made considerable progress in 60 years, half of transplant recipients are still victims of complications: side effects of conditioning pretreatment (that aims to prevent transplant rejection), long-term susceptibility to infections and GvHD. In the latter case, the donor’s over-active T-cells «turn against» the patient’s tissues: mucous membranes, gastro- intestinal tract, skin, liver and lungs. Less frequently, the acute form appears just after the transplant, the chronic form occurring several months later (preceded or not by an aGvHD). Affecting between 30 to 55% of patients, GvHD is the main complication of transplantation. To halt this “autoimmune disease”, physicians combine corticosteroids with other immunosuppressive agents. The fact remains that some 30 to 50% of aGvHD gradually become resistant to these first-line treatments. To date clinicians do not have any standard of treatment for these patients for whom there is a strong unmet medical need. Thus in Europe, 4,000 children and adults die each year from their aGvHD. 3 First & second-line systemic treatment of Acute Graft-versus-host Disease: Recommendations of the American Society of Blood and Marrow Transplantation, PJ Martin et al, Biol Blood Marrow TR, 2012 Aug;18(8):1150-63; DOI: 10.1016/j.bbmt.2012.04.005 ELB Leukotac PR 2 PRESS RELEASE About LEUKOTAC® LEUKOTAC® (inolimomab) is an immunotherapy monoclonal antibody that targets the interleukin-2 receptor (IL-2), a chemical molecule named cytokine that contributes to the development and proliferation of some white blood cells including T-cells responsible for aGvHD. By linking specifically to the α chain of the receptor (CD25), LEUKOTAC® prevents IL- 2 from binding on the surface of the donor’s over-active T-cells which blocks their multiplication. The efficacy of LEUKOTAC® in steroid-resistant aGvHD is primarily due to its specificity and its high affinity for the IL2 receptor, considerably higher than other drugs in the same class. About ELSALYS BIOTECH ELSALYS BIOTECH is a clinical stage immuno-oncology company that designs and develops a new generation of therapeutic antibodies that target tumors and their immune and/or vascular microenvironment. By modulating the action of immune cells (immunomodulator antibodies) or by blocking the mechanisms that promote tumor growth (targeted antibodies), ELSALYS BIOTECH intends to offer new options to patients for whom therapy is no longer an option. To convert these novel targets into drug candidates, the Company relies on a world-class academic network, a team and an R&D platform that encompasses targets sourcing to clinical development and the commercialization of monoclonal antibodies derived from these targets. Today ELSALYS BIOTECH is conducting 5 proprietary development programs including LEUKOTAC® (inolimomab), an immunotherapy antibody that has recently demonstrated its clinical superiority in Phase 3 in an orphan disease with very poor prognosis: steroid-resistant acute Graft-versus-Host Disease. Bringing LEUKOTAC® to the market could lead ELSALYS BIOTECH to build, by acquisitions, a portfolio of commercial immunotherapy antibodies against rare diseases. Founded in 2013, ELSALYS BIOTECH is located in the heart of the European cluster LYON BIOPOLE. Its founding shareholders are TRANSGENE and SOFIMAC PARTNERS, joined in 2015 by the INSTITUT MERIEUX EUROPE and CREDIT AGRICOLE CREATION. www.elsalysbiotech.com Stay in touch with ElsaLys Biotech and receive directly our press releases by filling our contact form on www.elsalysbiotech.com Contacts ELSALYS BIOTECH Press : Dr. Christine GUILLEN ATCG PARTNERS CEO and Co-founder Marie PUVIEUX (France) +33 (0)6 37 69 75 15 +33 (0)6 10 54 36 72 [email protected] Céline VOISIN (UK/US) +33 (0)6 62 12 53 39 [email protected] ELB Leukotac PR 3 .