Ad hoc announcement pursuant to Art. 53 LR

Allschwil, Switzerland, January 9, 2023

Spexis reports solid safety and pharmacokinetics results from first-in-human study with inhaled murepavadin, a novel macrocycle compound

• Inhaled murepavadin shown to be well tolerated at all dose levels
• Program derived from Spexis’ macrocycle platform
• Data support moving forward to Phase 2 in cystic fibrosis and non-cystic fibrosis bronchiectasis lung infection

Spexis AG (SIX: SPEX), a clinical-stage biopharmaceutical company focused on rare diseases and oncology, today announced the successful completion of the first-in-human clinical trial with novel class antibiotic murepavadin, delivered via the oral inhalation route (iMPV). iMPV is a macrocycle compound derived from Spexis’ proprietary platform and specifically targets the outer membrane of Pseudomonas aeruginosa (P. aeruginosa) including activity against highly resistant strains. P. aeruginosa is the key pathogen in cystic fibrosis (CF) lung infections. The study was supported by the European Innovative Medicines Initiative (IMI).

Juergen Froehlich, MD, Chief Medical Officer of Spexis, said: “The first clinical data with our inhaled murepavadin hold promise as we work to bring more efficacious and safe treatments for serious lung infections to patients in need, including people with cystic fibrosis and non-CF bronchiectasis. The strong collaboration established between Spexis and the European Innovative Medicines Initiative was an enabler for us to conduct this important first-in-human trial, and we are grateful for the IMI’s ongoing support. We look forward to continuing to advance this product candidate in clinical development.”

This Phase 1 trial was a single center, double-blind, randomized, placebo-controlled trial to investigate the safety, tolerability, and pharmacokinetics of single ascending doses of iMPV in healthy volunteers.

A total of 39 subjects participated in the trial. In Part A of the trial, three single dose levels (12.5 mg, 25mg, and 50 mg of iMPV) were evaluated in four subjects per cohort. In Part B, single doses of 75 mg, 150 mg, and 300 mg were evaluated in nine subjects per cohort. The pharmacokinetics (PK) of iMPV were assessed in blood samples and in epithelial lining fluid (ELF) obtained by bronchoalveolar lavage.

Analyses of the preliminary, blinded data from this study showed that iMPV was well tolerated at all dose levels, with all subjects completing the inhalation. No clinically relevant signs of irritation of the upper airways and no serious adverse events were reported. Serial pulmonary function tests were normal and did not show narrowing of the airways after administration of iMPV. Vital signs, ECGs and safety laboratory data were within the normal range.

At the highest single dose tested, systemic bioavailability of MPV was lower than 5%, and peak plasma concentrations were observed at 1-2 hours post start of inhalation. In the ELF, the concentration of MPV at the 24-hour timepoint was still above the concentration that would inhibit the growth of 90% of P. aeruginosa isolates (MIC90) obtained from people with CF.

These data indicate that iMPV leads to high inhibiting concentrations in the airways of the lung while systemic MPV levels remain substantially lower compared to the plasma level observed in previous clinical trials with intravenous administration of MPV. This observed favorable tolerability, safety and concentration profile of MPV after inhalation in the Phase 1 trial meets the company’s expectations and clears the way for further clinical trials of iMPV in people with CF or non-CF bronchiectasis.

About Spexis

Spexis (SIX: SPEX) is a clinical-stage biopharmaceutical company based in Allschwil, Switzerland, focused on rare diseases and oncology. For further information please visit: www.spexisbio.com.

For further information please contact:

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 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.