Vancouver, July 26, 2000 - Micrologix Biotech Inc. has completed a US Phase I human clinical trial demonstrating the safety of MBI 853NL, an antibiotic drug being developed for the prevention of hospital-acquired infections caused by Staphylococcus aureus (S. aureus). Micrologix will present the results of this study to the FDA and intends to initiate the next phase of clinical trials in the fourth quarter of this year.

The Phase I trial was designed as a randomized, double-blind, placebo-controlled study to assess the safety and tolerability of MBI 853NL applied intranasally to 30 healthy volunteers who are persistent carriers of nasal S. aureus. These subjects were treated for five days with follow-up evaluations performed up to one month following treatment. Although the primary purpose of the study was to assess safety in humans, qualitative nasal cultures were also taken from all subjects three days following completion of therapy (on Day 8).

The results from this trial demonstrated that MBI 853NL is safe and well tolerated, with no absorption into the bloodstream. Additionally, all clinical chemistry and hematology test results were normal. At the tested dosage, S. aureus was not completely eliminated as organisms were detected in the nasal cultures taken on Day 8. Micrologix plans to initiate a dose-escalation study in the fourth quarter of this year to further establish safety and quantify the anti-S. aureus activity of MBI 853NL.

Background on Nasal Carriage of S. aureus

S. aureus is one of the most important causes of the two million hospital-acquired infections that occur each year in the US. This organism is carried in the nasal passages of up to 40% of healthy adults. Clinicians have known for decades that individuals who are nasal carriers of S. aureus are at an increased risk of developing serious staphylococcal infections. Nasal carriers of S. aureus have at least a 3.5-fold increased risk of developing a surgical wound infection, and in certain groups of dialysis patients, the risk of infection is increased by up to 14-fold. Additionally, patients are at risk of being infected by S. aureus carried in the noses of hospital care workers. Studies have shown that eliminating or reducing S. aureus nasal carriage lowers the incidence of hospital-acquired infections and thus should decrease the associated cost of medical care.

The current arsenal of antimicrobial drugs for addressing S. aureus carriage is very limited and is diminishing with the onset of resistance to these agents. Due to its unique mode of action, Micrologix's MBI 853NL has superb antibiotic properties, killing both sensitive and methicillin-resistant strains of S. aureus (MRSA) and, as demonstrated in preclinical studies, does not generate resistance itself. These qualities offer significant advantages for the use of MBI 853NL in the infection-control practices of hospitals as well as an adjunctive therapy aimed at reducing the incidence of postoperative and other S. aureus infections.

Corporate Profile

Micrologix Biotech Inc. is a biopharmaceutical company developing novel drugs to treat severe and life-threatening diseases-particularly those caused by antibiotic-resistant microorganisms. Micrologix's portfolio of antibiotic drug candidates is based on improved analogs of the anti-infective peptides found in the host defense systems of most life forms. These peptides overcome conventional antibiotic resistance and extensive research done by Micrologix and independent researchers indicates that it will be extremely difficult for resistance to develop to them. In addition to MBI 853NL, Micrologix has two other drugs currently in clinical trials in the US — MBI 226 for the prevention of catheter-related bloodstream infections and MBI 594AN for the treatment of acne. Under FDA fast track designation, the Company plans to initiate a Phase III clinical trial of MBI 226 in September 2000. Micrologix completed a Phase I clinical trial of MBI 594AN in June and anticipates initiating further clinical trials in the fourth quarter of 2000.