FDA agree to enter clinical development programme

15 April 2015

Motif Bio plc

("Motif", the "Company" or with its subsidiary the "Group")

MOTIF GAINS FDA AGREEMENT TO ENTER PHASE 3 CLINICAL DEVELOPMENT WITH ICLAPRIM

Iclaprim safety and efficacy to be studied in two serious and life-threatening infections

London, 15 April 2015 - Motif Bio plc (LSE: MTFB), announced today that the U.S. Food and Drug Administration (FDA) has agreed to the proposed Phase 3 clinical development programme for the Company's lead product candidate, iclaprim. The Phase 3 programme is designed to obtain marketing approval for an intravenous formulation of iclaprim in the treatment of acute bacterial skin and skin structure infections (ABSSSI) and hospital acquired bacterial pneumonia (HABP) caused by Gram positive pathogens, including resistant strains such as MRSA (methicillin-resistant Staphylococcus aureus) and MDRSP (multi-drug resistant Streptococcus pneumoniae). The FDA confirmed that two ABSSSI trials or one ABSSSI trial plus one HABP trial meeting their pre-specified primary endpoints are required for approval of iclaprim. Motif is working to determine the costs and timeline of these options. Assuming that funds can be raised or a partnership can be entered into, the first Phase 3 trial for ABSSSI is expected to commence in the second half of 2015.

Iclaprim:

· is a novel, next generation diaminopyrimidine derivative belonging to the class of selective dihydrofolate reducatase (DHFR) inhibitors;

· is an antibiotic designed to be effective against bacteria that have developed resistance to other antibiotics, including trimethoprim, also a DHFR inhibitor;

· is at least as potent when administered alone as the combination of trimethoprim plus sulfamethoxazole against Gram-positive pathogens;

· exhibits potent in-vitro, bactericidal activity against Gram-positive pathogens and, based on in-vitro data, has a low propensity for the development of resistance; and

· has an established safety and efficacy profile and IV formulations of iclaprim have been compared to vancomycin and linezolid in clinical studies in more than 560 patients with complicated skin and skin structure infections ("cSSSI") and approximately 50 patients with hospital acquired bacterial pneumonia ("HABP").

Graham Lumsden, CEO of Motif, commented:

"We are pleased to confirm the positive results of our meeting with the FDA and are moving forward with our plans to initiate the Phase 3 clinical development programme for iclaprim in 2015. The programme will investigate the safety and efficacy of iclaprim in patients with ABSSSI and HABP, two serious and life threatening infections caused by multi-drug resistant bacteria. Resistance to antibiotics is a major global health threat and we believe that iclaprim, a novel antibiotic in the under-utilized dihydrofolate reductase inhibitor (DHFRi) class, can become an integral part of hospital doctors' life-saving treatment strategies.

We look forward to keeping the market and our partners updated on the progress of the various studies with iclaprim as we move forward."

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Notes to Editors

Motif is a clinical stage biopharmaceutical company, which specialises in developing novel antibiotics designed to be effective against serious and life-threatening infections caused by multi-drug resistant bacteria. The Company has a lead antibiotic candidate, iclaprim, in clinical development and MTF-001, a preclinical stage programme to design a best-in-class dihydrofolate reductase inhibitor (DHFRi).

Iclaprim is being developed for the treatment of the most common and serious bacterial infections such as acute bacterial skin and skin structure infections (ABSSSI) and hospital acquired bacterial pneumonia (HABP), including those caused by resistant strains such as MRSA (methicillin-resistant Staphylococcus aureus) and MDRSP (multi-drug resistant Streptococcus pneumoniae) that have become prevalent in patients in both the community and hospital settings.