XF-73 (exeporfinium chloride)

XF-73 is a synthetic dicationic porphyrin derivative with antibacterial activity. XF-73 has confirmed bactericidal activity.

XF-73 is designated by the International Non-proprietary Name (INN) of exeporfinium chloride by the World Healthcare Organisation (WHO)

XF-73 has a novel mechanism of action.

• The mechanism of action of XF-73 differs from that of any existing families of antimicrobial agents
• Published research studies indicate that the XF-drugs are bactericidal and act via a bacterial cell-surface mechanism that affects membrane permeability and integrity, leading to release of intracellular components and bacterial cell death, without lysis

XF-73 is active against all tested Staphylococcus aureus strains including methicillin-resistant and multi-drug resistant strains.

• XF-73 has been tested in vitro against a range of clinically important S. aureus isolates
• It is active against methicillin-resistant S. aureus (MRSA), methicillin-sensitive S. aureus (MSSA), hospital associated-MRSA (HA-MRSA) and community-acquired MRSA (CA-MRSA), daptomycin resistant S. aureus, low- and high-level mupirocin-resistant S. aureus, linezolid-resistant MRSA and vancomycin-intermediate S. aureus (VISA).

XF-73 exhibits rapid bactericidal activity against S. aureus

• XF-73 exhibits rapid bactericidal activity against S. aureus demonstrating a > 99.99% kill of S. aureus within 5 minutes.

XF-73 has a low potential for development of bacterial resistance

• In an extensive, published study, XF-73 showed no drug resistance emergence from four common MRSA strains tested in a multi-step (55 passage) resistance study

XF-73 has activity against a wide range of Gram positive bacteria

• XF-73 is active against all tested aerobic and anaerobic Gram positive bacteria (including Bacillus species [spp.], Corynebacterium spp., Enterococcus spp., Listeria monocytogenes, Staphylococcus spp. (including MRSA, MSSA, VISA, daptomycin-non-susceptible S. aureus, and low- and high-level mupirocin-resistant S. aureus), Streptococcus spp., Clostridium spp., Eggerthella lenta, Peptostreptococcus spp. and Propionibacterium acnes)

XF-73 also has activity against a number of Gram negative bacteria

• XF-73 is active against the following Gram negative bacteria: Acinetobacter baumannii, Haemophilus influenza, Moraxella catarrhalis, Neisseria meningitides, Providencia stuartii, Pseudomonas aeruginosa, Stenotrophomonas maltophilia, Porhyromonas assacharolyticus and Prevotella intermedia

XF-73 has activity against S. aureus within biofilms

• A further key property is XF-73’s ability to kill bacteria within biofilms
• In a S. aureus model, the minimum biofilm eradication concentration (MBEC) of XF-73 remained unchanged compared to the standard MIC, whilst those for all other antibiotics increased by at least 500 times.

XF-73 is a lead, clinical stage, drug asset having completed trials in the UK and USA