OSE Immunotherapeutics

Regulatory Filings • Oct 20, 2015

OSE Pharma to attend BIO-Europe 2015 The conference will take place on November 2-4 in Munich, Germany

Paris, October 20, 2015, 5:45 PM – OSE Pharma SA (ISIN: FR0012127173; Mnémo: OSE), an immuno-oncology company developing a T-specific immunotherapy for late-stage patients, announces it will attend the 21st edition of BIO-Europe on the 2nd and 3rd of November.

The annual conference BIO-Europe aims at fostering partnerships between companies and key players from the biotech industry. More than 3,000 delegates, representing nearly 1,700 companies, are expected to attend this year's edition of the event.

ABOUT OSE PHARMA

OSE Pharma is a biotech company that designs and develops cancer immunotherapy treatments using its Memopi® technology, which triggers a cytotoxic T-cell response and leads the immune system to destroy cancer cells.

Its lead product, Tedopi® (OSE-2101), is a T-specific immunotherapy treatment for cancer. A pivotal Phase 3 study will soon be launched in the U.S. and Europe in patients diagnosed with non-small cell lung cancer (NSCLC). It will target patients whose cells are expressing HLA-A2 antigens, a key receptor for the cytotoxic Timmune response that can be found in nearly 45% of patients with lung cancer. The objective of this pivotal study will be to evaluate the benefits of Tedopi® compared to current standard chemotherapy treatments (docetaxel or pemetrexed) in HLA-A2 positive patients. The primary endpoint of this trial will be overall survival (the Phase 2 study demonstrated a long survival of patients, considering how advanced their pathology was).

This Phase 3 study is expected to start by the end of 2015 and should be completed in 2018, provided that the recruitment of patients, their observed survival and the safety of the product meet the usual criteria for this kind of trials.

Tedopi® can be developed in Phase 2 in combination with other immunotherapeutic products or targeted therapies. It is also considered for other oncology indications (ovary, colon, prostate, breast) for HLA-A2 positive patients.

Tedopi® combines 10 optimized epitopes simultaneously acting against 5 tumor-associated antigens (TAAs). These 5 antigens have been selected because they are a factor of poor prognosis in several types of cancers. The 10 optimized epitopes, also known as neo-epitopes, have been selected and modified to enhance their binding to HLA-A2 and TCR receptors, and trigger a stronger T-cell response. These strong cytotoxic T-cell responses lead the immune system to destroy tumor cells expressing HLA-A2 antigens and one of the targeted tumor antigens (TCR).

OSE Pharma is listed on Euronext Paris (ISIN: FR0012127173; Mnémo: OSE). For more information, please visit www.osepharma.com

Press Contacts

OSE Pharma sa Dominique Costantini, CEO dominique.costantini@osepharma.com Mob +33 6 13 20 77 49

Alexis Peyroles, CFO Alexis.peyroles@osepharma.com Mob : +33 6 11 51 19 77

Citigate Dewe Rogerson Laurence Bault / Lucie Larguier +33 1 53 32 84 78 laurence.bault@citigate.fr

Alize RP

Florence Portejoie & Caroline Carmagnol +33 1 44 54 36 64 - + 33 6 47 38 90 04 fportejoie@alizerp.com

Disclaimer:

This press release may expressly or implicitly contain forward-looking statements relating to OSE Pharma and its activity. Although OSE Pharma's management believes that the expectations reflected in these forward-looking statements are reasonable, investors are cautioned that such statements are related to known or unknown risks, uncertainties and other factors that could lead actual results, financial conditions, performance or achievements to differ materially from OSE Pharma's results, financial conditions, performance or achievements expressed, projected or implied by such information and forward-looking statements.

Other than as required by applicable law (article 223-1 et seq of the General Regulation of the AMF), OSE Pharma issues this press release at the date hereof and does not undertake any obligation to update or revise any forward-looking information or statements.

These risks and uncertainties include among other things, the uncertainties inherent in future clinical data and analysis, including post marketing, decisions by regulatory authorities, such as the FDA or the EMA, regarding whether and when to approve any drug, and other matters that could affect the availability or commercial potential of such product candidates, the absence of guarantee that the product candidates if approved will be commercially successful, the future approval and commercial success of therapeutic alternatives, For a description of risks and uncertainties which could lead to discrepancies between actual results, financial condition, performance or

achievements and those contained in the forward-looking statements, please refer to Chapter 4 "Risk Factors" of the company's Documents de Base filed with the AMF under number I. 14-056 on September, 17th 2014 and Chapter 2 "Risk Factors related to the Offer" in the prospectus approved by the AMF under number 15-078 on 6th March 2015, which can be found on the websites of the AMF (www.amf-france.org) and of OSE Pharma (www.osepharma.com).