XF Drug Series

XF Drug Series

A new concept

By addressing the issue of resistance, the XF series and related DPD series represents an entirely different approach to the prophylaxis and treatment of infectious disease:

  • Structurally distinct from all existing therapies – dicationic porphyrins
  • Mechanism of action is fundamentally different from all antibiotics
  • Potentially offering major advantages in controlling drug-resistant bacteria
  • Highly potent against a broad spectrum of Gram positive bacteria
  • Bactericidal against methicillin-resistant Staphylococcus aureus (MRSA)
  • Likelihood of resistance developing is very remote
  • Equally effective against S. aureus within biofilms

XF Drugs have been shown to rapidly kill bacteria by interfering with the properties of the surface of bacteria, resulting in the loss of vital components from the cell, without bursting the cells themselves. XF Drugs have been shown to kill bacteria in all growth states, including non-growing cultures which are resistant to a large number of antibiotics, which depend on the bacteria actively growing to be able to kill them. In addition, XF Drugs have demonstrated the ability to kill Staphylococcal bacteria within biofilms – unlike most antibiotics.

Potent antibacterial action

XF Drugs have in vitro bactericidal activity against a wide range of bacteria. They have been shown to be effective at killing a wide range of Gram positive aerobic bacteria such as Staphylococcus spp. (multiple strains of MRSA, methicillin-susceptible S. aureus (MSSA), Staphylococcus epidermidis), Streptococcus spp, Corynebacterium spp. and Enterococcus spp. They are also active against Gram positive anaerobic bacteria such as Clostridium difficile and Propionibacterium acnes, and against some Gram negative aerobic and anaerobic bacteria.

Likelihood of resistance is very remote

S. epidermis bacteria

While the mechanism of action has yet to be fully elucidated, the XF series of drugs clearly act in a fundamentally different way compared with antibiotics and are therefore not predisposed to any of the current pathways by which drug resistance has developed. Indeed, in studies of XF-73 in MRSA, in contrast with traditional antibiotics, no resistance has emerged, even after 55 repeat passages! This data was published in the prestigious journal Antimicrobial Agents and Chemotherapy in June 2011 (Volume 55, pages 1177 to 1181)

Very remote likelihood of resistance


XF-73 molecule


XF-70 molecule


DPD-207 molecule