Recce Pharmaceuticals (ASX:RCE) has announced promising new preclinical results demonstrating that its lead anti-infective, RECCE 327 (R327), delivered via inhalation, can significantly reduce bacterial burden in a validated mouse model of hospital- and ventilator-acquired pneumonia.
These conditions are two of the most lethal and difficult-to-treat infections in critical care settings.
The study, conducted by the Murdoch Children’s Research Institute (MCRI), assessed R327 in a model of pneumonia caused by carbapenem-resistant Acinetobacter baumannii (CRAB), one of the world’s most dangerous antimicrobial-resistant pathogens. The company said the results confirm the compound’s “significant antibacterial activity against multidrug-resistant A. baumannii,” a bacterium associated with high mortality in intensive care units worldwide.
Forty mice received either R327, placebo, saline or meropenem, a last-resort antibiotic, through intranasal drops or nebulisation. Unlike meropenem, which cannot always be nebulised effectively due to solubility constraints, R327 demonstrated a significant practical advantage by being suitable for inhalation and ventilator-based delivery.
At 24 hours post-infection, animals treated with R327 showed a dramatic reduction in bacterial load compared to untreated and placebo groups. Both intranasal and nebulised delivery routes produced strong antibacterial effects, but nebulised R327 achieved the most striking results, creating a 4-log reduction, corresponding to greater than 99.99 per cent reduction in bacterial burden. The company noted that the nebulised cohort achieved bacterial counts approaching the lower limit of detection, indicating potent and highly localised infection control.
By contrast, meropenem reduced bacterial numbers but could only be administered intranasally due to solubility issues, limiting its utility in real-world hospital settings where nebulisation is critical for ventilated patients.
Recce CEO James Graham said the findings reinforce the potential of R327 as a practical and effective therapy in situations where current antibiotics fall short. “These results further validate the versatility of R327, administered as an inhaled formulation, as a potential treatment for serious, drug-resistant lung infections,” he said. “Unlike other antibiotics used against resistant pathogens, such as meropenem, which cannot be nebulised due to solubility limitations, R327 can be effectively delivered as a fine mist directly to the lung, precisely where the infection occurs.”
He added that the ability to deliver R327 through a nebuliser or ventilator “provides a significant real-world advantage in hospital settings, including intensive care and emergency environments where rapid, localised treatment is critical.”
Dr Sohinee Sarkar, Lead Investigator at Recce’s AIR Unit, said the data offer compelling support for further development. “These results add to a growing body of evidence demonstrating R327’s capacity to combat multidrug-resistant A. baumannii infections,” she said. “Given the challenges in treating CRAB-related pneumonia, these findings are highly encouraging for future clinical translation.”
R327 is one of three synthetic polymer anti-infectives in Recce’s pipeline, positioned as a new class of broad-spectrum agents designed to overcome antimicrobial resistance. The World Health Organization has listed R327, R435 and R529 on its roster of antibacterial candidates targeting priority pathogens, recognising the company’s efforts in the global race to develop alternatives to failing antibiotics.