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Spexis announces sale of preclinical antibiotics program to Basilea

Spexis AG / Key word(s): Disposal

15-Jan-2024 / 07:15 CET/CEST
Release of an ad hoc announcement pursuant to Art. 53 LR
The issuer is solely responsible for the content of this announcement.

Ad hoc announcement pursuant to Art. 53 LR

Allschwil, Switzerland, January 15, 2024

Spexis announces sale of preclinical antibiotics program to Basilea


  • Basilea to pay up to CHF 2 million for a preclinical program with novel antibiotics targeting Gram-negative bacteria, including multidrug-resistant strains
  • Preclinical studies demonstrated bactericidal activity in vitro and in vivo against a broad range of Gram-negative bacteria, including multidrug-resistant strains
  • Transaction is part of Spexis’ efforts to partner or divest non-core programs and assets as the company works through its moratorium status


Spexis AG (SIX: SPEX), a clinical-stage biopharmaceutical company focused on macrocycle therapeutics for rare diseases and oncology, today announced that it has entered into an asset purchase agreement with Basilea Pharmaceutica Ltd, Allschwil (SIX: BSLN) wherein Basilea will acquire from Spexis a preclinical program of antibiotics from a novel class targeting Gram-negative bacteria, including multidrug-resistant strains.1

The assets sold to Basilea are macrocyclic antibiotics developed within Spexis’ Outer Membrane Protein Targeting Antibiotics (OMPTA) program which selectively disrupt the lipopolysaccharide transport bridge, an essential structure in Gram-negative bacteria. This results in a loss of the integrity of the outer cell membrane, intracellular accumulation of lipopolysaccharides and killing of the bacteria. Activity has been shown in vitro and in vivo against Enterobacteriaceae such as E. coli and K. pneumoniae, including strains resistant to beta-lactams and colistin, an antibiotic regarded as last-resort therapy. The program was funded in part by CARB-X (Combating Antibiotic-Resistant Bacteria Biopharmaceutical Accelerator)2, a global non-profit partnership dedicated to supporting early-stage antibacterial research and development to address the rising threat of drug-resistant bacteria.

Jeff Wager, MD, Chairman & CEO of Spexis, said: “This transaction with Basilea underscores the power of our macrocycle platform as a drug discovery platform and its potential to generate products that can address significant unmet medical needs.  Furthermore, from a corporate strategy perspective, this transaction represents a continuation of our focus to partner or divest programs and assets not central to our rare disease and oncology focus as we pursue an exit from our moratorium status. The assets sold to Basilea are a novel class of antibiotics discovered and optimized using Spexis’ proprietary macrocycle platforms and methodologies.  In this case, the compounds derivatized target the lipopolysaccharide transport in Gram-negative bacteria which have been highlighted by the World Health Organization as priority pathogens against which new antibiotics are urgently needed. ”

Basilea is acquiring all program compounds, including intellectual property, and is paying Spexis up to a total of CHF 2 million, which consists of an upfront payment, a payment related to the near-term transfer of the assets to Basilea, and a potential final milestone payment related to the availability of near-term external funding for the further development of the program. In addition, Basilea is assuming the rights and obligations of Spexis related to the program, including potential low single-digit percentage royalties on sales, under licensing agreements. The transaction is subject to the approval by the Western District Court of the Canton Basel-Landschaft.

About multidrug-resistant Gram-negative bacteria

Infections by multidrug-resistant Gram-negative bacteria (GNB) are a major challenge for healthcare professionals. Due to an additional outer cell membrane compared to Gram-positive bacteria, it is more difficult for antibiotics to get into the cell. In addition, this outer membrane carries lipopolysaccharides/endotoxins which induce inflammation and play an important amplifying role in the pathogenesis of infections by GNB and are therefore considered an important virulence factor. Moreover, GNB can acquire resistance to several classes of antibiotics such as carbapenems, fluoroquinolones, tetracyclines and earlier-generation cephalosporins, making infections with GNBs particularly difficult to treat. In 2017, the World Health Organization published a list of 12 classes of priority bacterial pathogens that pose the greatest threat to human health, of which nine classes are Gram-negative.3

About Spexis

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

About Spexis’ Macrocycle Platforms

Spexis possesses what we regard as some of the most distinct, highly diverse and very well characterized macrocycle libraries in the world, together with deep data on same, developed over the course of more than 25 years of research and development and significant investment.  These include PEMFinder™, which is comprised of peptidomimetic macrocycles, and MACROFinder™, which are small molecule macrocycles.  Each have distinct applications depending on the targets in question, which can be both extracelluar and intracellular targets.  In addition to generating the specific OMPTA candidates described in this press release, these platforms have generated multiple other drug candidates in the Spexis pipeline, including murepavidin, balixafortide, lonodelestat and others. 


For further information please contact:

For Investors: 
Stephen Jasper
Managing Director
Gilmartin Group
For Media:
Dr. Stephan Feldhaus
Feldhaus & Partner
+41 79 865 9256


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.

This press release can be downloaded from


  1. 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
  2. Research reported in this press release is supported by CARB-X. CARB-X’s funding for this project is provided in part with federal funds from the US Department of Health and Human Services; Administration for Strategic Preparedness and Response; Biomedical Advanced Research and Development Authority under agreement number 75A50122C00028; and by awards from Wellcome (WT224842), and Germany’s Federal Ministry of Education and Research (BMBF). The content of this press release is solely the responsibility of the authors and does not necessarily represent the official views of CARB-X or any of its funders.
  3. (Accessed: January 11th, 2024)


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