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Allschwil, Switzerland, March 23^rd, 2018

Polyphor presents positive proof of concept data for innovative immuno-oncology candidate balixafortide at European Breast Cancer Conference

Polyphor announced today the presentation of positive data from its Phase Ib/proof of concept clinical trial for its novel immuno-oncology candidate balixafortide (POL6326), a potent and highly selective antagonist of CXCR4, a G-protein coupled receptor (GPCR) that regulates the trafficking and homing of both cancer cells and cells of the patient's immune system. The data was presented at the 11^th European Breast Cancer Conference in Barcelona^[a].

The open label study recruited 56 patients with metastatic breast cancer who had previously received one to three chemotherapeutic regimes. Patients received increasing doses of balixafortide (0.5 - 5.5 mg/kg) alongside eribulin. An expanded cohort received the combination of eribulin and the recommended Phase II tolerated dose of balixafortide.

In the expanded cohort (n=24), balixafortide combined with eribulin showed a 63% Clinical Benefit Rate (CBR) and a 38% Overall Response Rate (ORR)^[i]. The safety and tolerability of the combination appeared comparable to published data on either eribulin or balixafortide monotherapy.

"We believe the data presented today show balixafortide to be the first CXCR4 inhibitor to demonstrate proof of concept in solid tumors," said Dr. Debra Barker, Chief Medical and Development Officer of Polyphor. "This trial underlines the potential of balixafortide to provide a new treatment option for patients with late stage HER2 negative breast cancer where there remains a significant unmet medical need. Following our recent end of Phase I meeting with the U.S. Food and Drug Administration (FDA), we have identified specific next steps towards a pivotal trial to potentially support registration for balixafortide in the U.S. and look forward to advancing this clinical program."

About Balixafortide (POL6326)
Balixafortide is a potent and highly selective antagonist of CXCR4, a G-protein coupled receptor (GPCR) that regulates the trafficking and homing of both cancer cells and cells of the patient's immune system. CXCR4 plays a critical role in tumor growth, survival, angiogenesis and metastasis^[ii]. High CXCR4 levels have been detected in almost all human tumor types, including breast cancer. High CXCR4 expression is known to correlate with aggressive metastatic behavior of cancer cells and a poor prognosis^[iii].

In a clinical proof-of-concept trial in patients with advanced metastatic breast cancer, the combination of balixafortide with eribulin has shown a 63% Clinical Benefit Rate (CBR) and a 38% Overall Response Rate (ORR)ⁱ. In its registration trial for the USA ("EMBRACE" trial) eribulin alone showed a CBR of 28% and an ORR of 13%^[iv]. In addition to its eribulin combination program for metastatic breast cancer, Polyphor is also conducting preclinical work to establish the potential for balixafortide in combination with other drugs and in other indications.

About Polyphor
Polyphor is a clinical stage, privately held Swiss specialty pharma company which has discovered and is developing the OMPTA (Outer Membrane Protein Targeting Antibiotics). The OMPTA are potentially the first new class of antibiotics against Gram-negative bacteria to have reached phase III stage in the last 50 years. The company's lead product, murepavadin, (POL7080) is in Phase III development against Pseudomonas aeruginosa - recognized as a critical priority 1 pathogen by WHO. Polyphor is also developing an immuno-oncology candidate, balixafortide (POL6326), which has achieved clinical proof of concept in a Phase Ib/proof of concept study in combination with eribulin in patients with advanced breast cancer, and a pipeline of further preclinical antibiotics based on its OMPTA platform. Polyphor is based in Allschwil near Basel. For more information, please visit www.polyphor.com.

For further information please contact:

Franziska Daabour
Communications
Polyphor Ltd.
Tel: +41 61 567 16 00
Email: PR@polyphor.com

For Investors:

Kalina Scott
Chief Financial Officer
Polyphor Ltd.
Tel: +41 61 567 16 67
Email: PR@polyphor.com

^[a] Balixafortide (a CXCR4 antagonist) plus eribulin in HER2-negative metastatic breast cancer (MBC): a Phase I open-label trial. P.A. Kaufman, S. Pernas, M. Martin|, M. Gil-Martin, P. Gomez Pardo, L.T. Sara, L. Manso, E. Ciruelos, J.A. Perez-Fidalgo, C. Hernando, F.O. Ademuyiwa, K. Weilbaecher, I. Mayer, T.J. Pluard, M. Martinez Garcia, L. Vahdat, A. Wach, D. Barker, B. Romagnoli, J. Cortes. Abstract number: 405. Friday 23rd March 2018, 09:15 - 15:00
^[i] Gil-Martin M. et al. Phase 1 study of the combination of balixafortide (CXCR4 inhibitor) and eribulin in HER2-negative metastatic breast cancer (MBC) patients. J Clin Oncol. 2017;35(15_suppl):2555-2555
^[ii] Otsuka S, Bebb G. J Thorac Oncol. 2008;3(12):1379-1383
^[iii] Chatterjee S, Behnam Azad B, Nimmagadda S. Adv Cancer Res. 2014; 124:31-82
^[iv] "Embrace" registration trial for Eribulin