Basilea awarded additional CARB-X funding of USD 6 million to support the clinical development of antibiotic BAL2420

• Funding is awarded following successful completion of IND-enabling studies and clinical study authorization 
• USD 6 million in additional funding to support antibiotic BAL2420 (LptA inhibitor) first-in-human clinical study

Ad hoc announcement pursuant to Art. 53 LR

Allschwil, Switzerland, April 09, 2026

Basilea Pharmaceutica Ltd, Allschwil (SIX: BSLN), a commercial-stage biopharmaceutical company committed to meeting the needs of patients with severe bacterial and fungal infections, announced today that it was awarded an additional USD 6 million from CARB-X (Combating Antibiotic-Resistant Bacteria Biopharmaceutical Accelerator), a global non-profit partnership dedicated to supporting the early development of antibacterial products. The additional non-dilutive funding will support the first-in-human phase 1 clinical study of Basilea’s novel antibiotic BAL2420 (LptA inhibitor)¹ and related activities. The phase 1 study has already been initiated, with the first subject dosed in March 2026.

Dr. Marc Engelhardt, Chief Medical Officer of Basilea, said: “We are very pleased with CARB-X’s continued support, as we advance our promising first-in-class LptA inhibitor through early clinical development. BAL2420 offers a new mode of action with the potential to address significant unmet medical needs in the treatment of severe Gram-negative bacterial infections including those caused by multidrug-resistant bacteria. We look forward to continuing our collaboration with CARB-X as we generate initial clinical data and bring BAL2420 closer to patients.”

Dr. Richard Alm, Interim Chief of Research and Development of CARB-X, commented: “Sustained funding and collaboration with innovative companies such as Basilea are critical to the development of novel antibacterial treatments that are of critical importance. BAL2420 represents a novel approach to tackling serious Gram‑negative infections, an area of significant unmet medical need. We look forward to continuing our collaboration with Basilea as BAL2420 advances through early clinical development.”

BAL2420 belongs to one of the very few novel classes of antibiotics in clinical development. It is targeting LptA, which is part of the lipopolysaccharide transport bridge, an essential structure in Gram-negative bacteria. LptA inhibitors have shown potent and rapid bactericidal activity in vitro and in vivo against Gram-negative bacteria of the Enterobacteriaceae family, such as E. coli and K. pneumoniae, including strains resistant to beta-lactams and colistin, an antibiotic regarded as last-resort therapy.² The Centers for Disease Control and Prevention (CDC) and the World Health Organization (WHO) have identified Enterobacteriaceae, including carbapenem-resistant strains, as high priority pathogens for which new and effective antibiotic treatments are urgently needed.^{3, 4}

CARB-X has supported the development of BAL2420 since 2020, advancing the project from the hit-to-lead stage to the first-in-human study. Research reported in this publication is supported by CARB-X. CARB-X is funded in part with federal funds from the U.S. Department of Health and Human Services (HHS); Administration for Strategic Preparedness and Response; Biomedical Advanced Research and Development Authority (BARDA) under agreement number 75A50122C00028 and by awards from Wellcome (WT224842), the UK Department of Health and Social Care’s Global Antimicrobial Resistance Innovation Fund (GAMRIF), the Gates Foundation, Germany’s Federal Ministry of Research, Technology and Space (BMFTR), the Novo Nordisk Foundation, Italy’s Ministry of Economy and Finance (MEF), Japan’s Ministry of Health, the European Commission’s DG Health Emergency Preparedness and Response Authority (DG HERA), and KfW Development Bank. The U.S. National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health (NIH) in HHS, provides support in the form of in-kind services through access to a suite of preclinical services for product development. The content of this publication is solely the responsibility of the authors and does not necessarily represent the official views of CARB-X or its funders.

About CARB-X

CARB-X (Combating Antibiotic-Resistant Bacteria Biopharmaceutical Accelerator) is a global non-profit partnership dedicated to supporting early-stage antibacterial research and development to address the rising threat of drug-resistant bacteria. CARB-X supports innovative therapeutics, preventatives and rapid diagnostics. CARB-X is led by Boston University and funded by a consortium of governments and foundations. CARB-X funds only projects that target the most serious, resistant bacteria identified on global priority lists, syndromes with the greatest global morbidity and mortality, and performance characteristics necessary for patients. https://carb-x.org/

About Basilea

Basilea is a commercial-stage biopharmaceutical company founded in 2000 and headquartered in Switzerland. We are committed to discovering, developing and commercializing innovative drugs to meet the needs of patients with severe bacterial and fungal infections. We have successfully launched two hospital brands, Cresemba for the treatment of invasive fungal infections and Zevtera for the treatment of bacterial infections. In addition, we have preclinical and clinical anti-infective assets in our portfolio. Basilea is listed on the SIX Swiss Exchange (SIX: BSLN). Please visit basilea.com.

Disclaimer

This communication expressly or implicitly contains certain forward-looking statements, such as “believe”, “assume”, “expect”, “forecast”, “project”, “may”, “could”, “might”, “will” or similar expressions concerning Basilea Pharmaceutica Ltd, Allschwil and its business, including with respect to the progress, timing and completion of research, development and clinical studies for product candidates. Such statements involve certain known and unknown risks, uncertainties and other factors, which could cause the actual results, financial condition, performance or achievements of Basilea Pharmaceutica Ltd, Allschwil to be materially different from any future results, performance or achievements expressed or implied by such forward-looking statements. Basilea Pharmaceutica Ltd, Allschwil is providing this communication as of this date and does not undertake to update any forward-looking statements contained herein as a result of new information, future events or otherwise.

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This ad hoc announcement release can be downloaded from www.basilea.com.

References

1. ClinicalTrials.gov identifier: NCT07500181
2. M. Schuster, E. Brabet, K. K. Oi et al. Peptidomimetic antibiotics disrupt the lipopolysaccharide transport bridge of drug-resistant Enterobacteriaceae. Science Advances 2023 (9), eadg3683
3. https://www.who.int/news/item/27-02-2017-who-publishes-list-of-bacteria-for-which-new-antibiotics-are-urgently-needed (Accessed: April 08, 2026)
4. https://www.who.int/news/item/13-10-2025-who-warns-of-widespread-resistance-to-common-antibiotics-worldwide
   (Accessed: April 08, 2026)

Attachment

• Ad hoc announcement