XF-73 Nasal for Post Surgical Infections
Professor Alex Mericli presents at the Destiny Pharma R&D Investor Update meeting – 18th October 2022
A Phase 2b clinical study, which was a multi-centre, randomized, placebo-controlled study of XF-73 nasal gel as a new product for the prevention of the incidence of post-surgical infections such as methicillin-resistant Staphylococcus aureus (MRSA) completed recruitment at the end of 2020 and top-line results were reported in Q1 2021, as planned.
The XF-73 nasal gel also demonstrated an excellent safety profile, with no treatment related adverse events reported. For more information on the trial results, please see here. The latest developments towards the Phase 3 study design are summarised here.
The primary efficacy endpoint of the Phase 2b study was met, with an exceptionally high statistical significance and XF-73 nasal gel reduced the mean nasal burden of Staphylococcus aureus in patients undergoing open heart surgery by 2.5 log (CFU/ml) in the 24 hours immediately before surgery, which equates to a 99.5% reduction in Staphylococcus aureus bacterial nasal carriage, which is a very effective reduction by accepted clinical measures. These positive results were achieved with just four doses of XF-73 nasal gel in the 24 hours before incision and the start of surgery. XF-73 also showed a 2.1 log, (>99%), greater reduction than placebo in the same patient population and the effect was maintained during surgery, considered the period when the risk for infections is the highest.
In February 2013, the US Surgical Infection Society (“SIS”), the Society for Hospital Epidemiologists of America (“SHEA”), the Infectious Disease Society of America (“IDSA”) and the American Society of Hospital Pharmacists (“ASHP”) published new guidelines recommending that in the US all Staphylococcus aureus (including MRSA) should be decolonised in all cardiovascular and most orthopaedic surgeries. This represents a five to tenfold increase in the market size for Staphylococcus aureus decolonisation in the US. In 2014, AHRQ/IDSA/SHEA recommended an even more aggressive treatment strategy, Universal Decolonisation (“UD”) of all intensive care unit (“ICU”) patients without screening, awarding a Grade I (highest) level of evidence rating. US hospital groups, including the Hospital Corporation of America, are now implementing UD for all patients entering the ICU. This market has a potential patient population of over eight million people in the US alone. UD of ICU patients represents a potentially attractive line extension for XF-73 where its rapid anti-bacterial action and attractive resistance profile could enable this preventative measure into the future.
In Europe, similar guidelines exist recommending decolonisation of Staphylococcus aureus positive patients prior to certain surgeries. The antibiotic, mupirocin, is often used off-label in the US for these applications, although it has two key disadvantages in that it is slow acting, requiring five days of dosing, and staphylococcal resistance to mupirocin can develop rapidly and become widespread. Consequently, many guidelines are accompanied with a resistance warning related to mupirocin use.
In 2016, the WHO published its Global Guidelines for the Prevention of Surgical Site Infection, which now too recommend the screening and decolonisation of all Staphylococcus aureus strains pre-surgery in high risk surgeries. It is therefore apparent that there has been a move from screening and treatment of just MRSA carriage in patient populations to also now include all Staphylococcus aureus strains (MRSA and MSSA), an approximate five to tenfold increase in the number of patients who can benefit.