Safety and efficacy of inhaled IBIO123 for mild-to-moderate COVID-19: a randomised, double-blind, dose-ascending, placebo-controlled, phase 1/2 trial.

BACKGROUND: COVID-19 severity is associated with its respiratory manifestations. Neutralising antibodies against SARS-CoV-2 administered systemically have shown clinical efficacy. However, immediate and direct delivery of neutralising antibodies via inhalation might provide additional respiratory clinical benefits. IBIO123 is a cocktail of three, fully human, neutralising monoclonal antibodies against SARS-CoV-2. We aimed to assess the safety and efficacy of inhaled IBIO123 in individuals with mild-to-moderate COVID-19. METHODS: This double-blind, dose-ascending, placebo-controlled, first-in-human, phase 1/2 trial recruited symptomatic and non-hospitalised participants with COVID-19 in South Africa and Brazil across 11 centres. Eligible participants were adult outpatients (aged ≥18 years; men and non-pregnant women) infected with COVID-19 (first PCR-confirmed within 72 h) and with mild-to-moderate symptoms, the onset of which had to be within 10 days of randomisation. Using permuted blocks of four, stratified by site, we randomly assigned participants (1:3) to receive single-dose placebo or IBIO123 (1 mg, 5 mg, or 10 mg) in phase 1, and single-dose placebo or IBIO123 (10 mg) in phase 2, in addition to local standard of care. Participants underwent serological testing to identify antibodies against SARS-CoV-2. Participants, investigators, and the study team were masked to treatment assignment. In phase 1, the primary outcome was the safety assessment in the safety population (ie, all participants who received an intervention). In phase 2, the primary outcome was the mean absolute change from baseline to day 5 in SARS-CoV-2 viral load measured by nasopharyngeal swabs analysed using a mixed model for repeated measures in the full analysis set (FAS; ie, participants with one analysable viral load value at baseline and at least one analysable viral load value at day 3 or day 5). Secondary clinical outcomes included safety from baseline to day 29, assessed by evaluating adverse events; the effect of IBIO123 on baseline COVID-19 symptoms resolution until day 6, with symptoms systemically evaluated by the investigators; and disease progression as measured by the COVID-19 WHO Clinical Progression Scale. For clinical endpoints in phase 2, we used a modified FAS (ie, participants who had at least one analysable viral load value over the course of the study, confirming that they were infected with SARS-CoV-2). This trial is now completed and is registered with ClinicalTrials.gov, NCT05298813. FINDINGS: Between Dec 4, 2021, and May 23, 2022, 24 participants were enrolled in phase 1. Between July 20, 2022, and Jan 4, 2023, 138 participants were enrolled in phase 2 and five were excluded because they did not meet the inclusion criteria. Participants were randomly assigned to receive IBIO123 (n=18) or placebo (n=6) in phase 1, and randomly assigned to receive IBIO123 (n=104) or placebo (n=34) in phase 2. In phase 2, the study was stopped before reaching the planned accrual because of a decline in COVID-19 incidence. In phase 1, no safety issues were observed. In phase 2, the difference in mean absolute change from baseline viral load to day 5 between participants in the IBIO123 group and participants in the placebo group was -0·29 log10 copies per mL (95% CI -1·32 to 0·75; p=0·45) in the FAS population and -0·49 log10 copies per mL (-1·56 to 0·58; p=0·20) in seropositive participants. In the modified FAS, 81 (69%) of 118 participants were at high risk of severe disease progression. The number of participants with resolution of respiratory symptoms at day 6 was 34 (42%) of 81 in the IBIO123 group versus five (17%) of 29 in the placebo group (p=0·017) in the modified FAS population and 19 (35%) of 55 versus three (14%) of 21 among participants at high risk (p=0·083). One participant died and one participant was hospitalised in the placebo group, whereas no deaths or hospitalisations were reported in the IBIO123 group. 39 (38%) of 104 participants in the IBIO123 group had adverse events, compared with 13 (38%) of 34 in the placebo group. INTERPRETATION: Inhalation of IBIO123 was safe. Despite the lack of significant reduction of viral load at day 5, treatment with IBIO123 resulted in a higher proportion of participants with complete resolution of respiratory symptoms at day 6. This study supports further clinical research on inhaled monoclonal antibodies in COVID-19 and respiratory diseases in general. FUNDING: Canadian Strategic Innovation Fund and Immune Biosolutions.

In vitro antibiotic susceptibility and biofilm production of Staphylococcus aureus isolates recovered from bovine intramammary infections that persisted or not following extended therapies with cephapirin, pirlimycin or ceftiofur.

Staphylococcus aureus intramammary infections (IMIs) have low cure rates using standard antibiotic treatment and increasing the duration of treatment usually improves therapeutic success. Chronic IMIs are thought to be caused by bacteria presenting a specific virulence phenotype that includes the capacity to produce greater amounts of biofilm. In this study, antibiotic susceptibility and biofilm production by S. aureus isolates recovered from IMIs that were cured or not following an extended therapy with cephapirin, pirlimycin or ceftiofur for 5, 8 and 8 days, respectively, were compared. An isolate was confirmed as from a persistent case (not cured) if the same S. aureus strain was isolated before and after treatment as revealed by the same VNTR profile (variable number of tandem repeats detected by multiplex PCR). The antibiotic minimal inhibitory concentrations (MICs) were determined for these isolates as well as the capacity of the isolates to produce biofilm. Isolates from persistent cases after extended therapy with cephapirin or ceftiofur had higher MICs for these drugs compared to isolates from non-persistent cases (p < 0.05) even though the antibiotic susceptibility breakpoints were not exceeded. Isolates of the ceftiofur study significantly increased their biofilm production in presence of a sub-MIC of ceftiofur (p < 0.05), whereas isolates from the pirlimycin group produced significantly less biofilm in presence of a sub-MIC of pirlimycin (p < 0.001). Relative antibiotic susceptibility of the isolates as well as biofilm production may play a role in the failure of extended therapies. On the other hand, some antibiotics may counteract biofilm formation and improve cure rates.

Interspecific small molecule interactions between clinical isolates of Pseudomonas aeruginosa and Staphylococcus aureus from adult cystic fibrosis patients.

Pseudomonas aeruginosa and Staphylococcus aureus are the most prevalent pathogens in airway infections of cystic fibrosis (CF) patients. We studied how these pathogens coexist and interact with each other. Clinical isolates of both species were retrieved from adult CF patients. Culture supernatants from 63 P. aeruginosa isolates triggered a wide range of biofilm-stimulatory activities when added to the culture of a control S. aureus strain. The extent of biofilm formation by S. aureus was positively correlated to the levels of the 2-alkyl-4-(1H)-quinolones (AQs) Pseudomonas Quinolone Signal (PQS) and 2-heptyl-4-hydroxy quinoline N-oxide (HQNO) produced by the P. aeruginosa isolates. Supernatants from P. aeruginosa isogenic mutants deficient in PQS and HQNO production stimulated significantly less biofilm formation by S. aureus than that seen with the parental strain PA14. When studying co-isolated pairs of P. aeruginosa and S. aureus retrieved from patients showing both pathogens, P. aeruginosa supernatants stimulated less biofilm production by the S. aureus counterparts compared to that observed using the control S. aureus strain. Accordingly, some P. aeruginosa isolates produced low levels of exoproducts and also some of the clinical S. aureus isolates were not stimulated by their co-isolates or by PA14 despite adequate production of HQNO. This suggests that colonization of the CF lungs promotes some type of strain selection, or that co-existence requires specific adaptations by either or both pathogens. Results provide insights on bacterial interactions in CF.

SigB is a dominant regulator of virulence in Staphylococcus aureus small-colony variants.

Staphylococcus aureus small-colony variants (SCVs) are persistent pathogenic bacteria characterized by slow growth and, for many of these strains, an increased ability to form biofilms and to persist within host cells. The virulence-associated gene expression profile of SCVs clearly differs from that of prototypical strains and is often influenced by SigB rather than by the agr system. One objective of this work was to confirm the role of SigB in the control of the expression of virulence factors involved in biofilm formation and intracellular persistence of SCVs. This study shows that extracellular proteins are involved in the formation of biofilm by three SCV strains, which, additionally, have a low biofilm-dispersing activity. It was determined that SigB activity modulates biofilm formation by strain SCV CF07-S and is dominant over that of the agr system without being solely responsible for the repression of proteolytic activity. On the other hand, the expression of fnbA and the control of nuclease activity contributed to the SigB-dependent formation of biofilm of this SCV strain. SigB was also required for the replication of CF07-S within epithelial cells and may be involved in the colonization of lungs by SCVs in a mouse infection model. This study methodically investigated SigB activity and associated mechanisms in the various aspects of SCV pathogenesis. Results confirm that SigB activity importantly influences the production of virulence factors, biofilm formation and intracellular persistence for some clinical SCV strains.