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Allschwil, Switzerland, July 7, 2022

Spexis' CXCR4 inhibitor balixafortide demonstrates synergistic efficacy in combination with docetaxel in a metastatic prostate cancer preclinical model

SPEXIS AG (SIX: SPEX), a clinical-stage biopharmaceutical company, today announced that its CXCR4 inhibitor balixafortide demonstrated synergistic efficacy in combination with docetaxel compared to either drug alone in a metastatic prostate cancer preclinical model.

Balixafortide is a potent and selective clinical-stage CXCR4 inhibitor. Spexis is currently evaluating various development opportunities for this program, including in hematological and solid tumors, as well as certain rare diseases beyond oncology.

In vivo study in collaboration with the University of Michigan

The preclinical study of metastatic prostate cancer combining balixafortide (20 mg/kg twice daily in mice, corresponding to a clinically relevant dose) and docetaxel (5 mg/kg once weekly) assessed tumor burden and tumor-induced bone degradation. Overall, results showed superior synergistic efficacy compared to either drug alone.

For measuring tumor burden, PC3-luc tumor cells were assessed by bioluminescence imaging, while bone resorption was analyzed by tartrate-resistant acid phosphatase (TRAcP) serum levels. Animals that received treatment had lower TRAcP levels than the vehicle group (p = 0.01). The combination of balixafortide and docetaxel decreased the total tumor burden significantly (p = 0.009). In addition, tumor-induced bone degradation was assessed by radiography and biomarkers. Radiograph imaging of the tibia on the day of study end demonstrated that animals receiving a combination of balixafortide and docetaxel showed less overall bone degradation from PC3-luc tumor cells.

Additional studies are in preparation to investigate the anti-metastatic mechanisms of action in more detail. The experiments were performed pursuant to a research collaboration with Professor Evan T. Keller from the University of Michigan.

“The decrease we saw in tumor burden with the combination of balixafortide and docetaxel is encouraging because we have chosen rigorous experimental conditions for both compounds to work alone”, said Evan T. Keller, DVM, PhD, Professor of Urology and Pathology, School of Medicine, University of Michigan. “Despite the availability of new treatments for prostate cancer, for patients whose disease has metastasized there remains a need for better treatment options. These data support further evaluation of this combination in this indication.”

“These results are encouraging that balixafortide may have significant potential in the treatment of metastatic prostate cancer and other solid tumors. The study reported in this press release is part of our ongoing evaluation of potential indications for the further development of balixafortide. Spexis is evaluating opportunities in solid tumors, hematologic tumor indications and rare diseases such as primary immunodeficiencies (PIDs). We will announce further plans in due course”, added Jeff Wager, M.D., Chairman and Chief Executive Officer of Spexis AG.

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About Spexis
Spexis is a clinical-stage biopharmaceutical company based in Allschwil, Switzerland, focused on rare diseases and oncology and trades on the SIX Swiss Exchange under the symbol SIX:SPEX. For further information please visit: www.spexisbio.com.

About Balixafortide
Balixafortide is a potent, specific and highly selective inhibitor of the chemokine receptor CXCR4, a G-protein coupled receptor that regulates the trafficking and homing of both cancer and immune system cells. CXCR4 is a promising target for therapy of both hematologic and solid tumors, as well as for other non-oncology indications. Following the termination of the Phase 3 FORTRESS study in advanced breast cancer in 2021, Spexis is evaluating additional oncology and non-oncology indications for balixafortide. Balixafortide was discovered via the company’s proprietary macrocycle drug discovery platform. In addition, via this platform, Spexis is discovering and developing a CXCR4/CXCR7 inhibitor pipeline focused on resistant hematologic malignancies, and for rare disease, anti-inflammatory and anti-viral indications as well.

Disclaimer
This press release contains forward-looking statements which are based on current assumptions and forecasts of Spexis management. Known and unknown risks, uncertainties, and other factors could lead to material differences between the forward-looking statements made here and the actual development, in particular Spexis' results, financial situation, and performance. Readers are cautioned not to put undue reliance on forward-looking statements, which speak only as of the date of this communication. Spexis disclaims any intention or obligation to update and revise any forward-looking statements, whether as a result of new information, future events or otherwise.