Decreasing staphylococcus aureus infections in colonized patients

Abstract

This invention relates to a method for treating individuals colonized with Staphylococcus aureus using anti-alpha toxin antibodies or their antigen-binding fragments. This method can reduce the incidence of infections in the individual associated with the presence of Staphylococcus aureus.

Description

[Previous Technology] Bacterial pneumonia occurring in hospitalized or intensive care unit (ICU) patients is a significant and serious clinical condition, contributing substantially to morbidity and mortality. It constitutes the second leading type of nosocomial infection in the United States and is the leading cause of death from nosocomial infections (Spellberg and Talbot, 2010). Staphylococcus aureus is the primary cause of nosocomial pneumonia. A recent study in European ICUs reported that 23% of mechanically ventilated ICU patients developed Staphylococcus aureus pneumonia, with more than half of these cases caused by methicillin-resistant Staphylococcus aureus (MRSA) (Esperatti et al., 2010). Staphylococcus aureus also causes a wide range of other diseases, including skin and soft tissue infections, endocarditis, osteomyelitis, pneumonia, and bacteremia (Lowy, FD, N. Engl. J. Med., 339(8): 520-32 (1998)). During infection, Staphylococcus aureus releases many toxins, among which alpha toxin (AT), the most prevalent virulence factor, causes tissue infiltration and necrosis (Wilke and Bubeck Wardenburg, 2010). The key role of AT in the pathogenesis of Staphylococcus aureus is supported by animal models (skin necrosis, pneumonia, sepsis, endocarditis, and mastitis) and observational studies in humans, in which the presence of anti-AT antibodies during severe infections is associated with improved outcomes. Preclinical studies indicate that monoclonal antibody-based approaches are promising for the prevention and adjunctive treatment of Staphylococcus aureus infection (see, for example, Hazenbos et al., PLoS Pathog., 9(10):e1003653. doi: 10.1371 / journal.ppat.10036532013 (2013); Rouha, H., MAbs, 7(1): 243-254 (2015); Foletti et al., J. Mol. Biol., 425(10): 1641-1654 (2013); Karauzum et al., J Biol Chem., 287(30): 25203-15 (2012); and Hua et al., Antimicrob Agents Chemother., 58(2): 1108-17 (2014)). Anti-AT antibodies have shown promising results in their ability to treat and prevent Staphylococcus aureus infections. MEDI4893, or suvratoxumab, is a human monoclonal antibody with an extended half-life that binds to AT with high affinity and effectively blocks AT pore formation in target cell membranes. Preclinical results have demonstrated that prophylaxis with anti-AT antibodies containing the MEDI4893 binding region reduces disease severity in murine infection models of skin necrosis, pneumonia, and lethal bacteremia / septicemia (see, for example, WO 2012 / 109285 and WO 2014 / 074540, the full text of which is incorporated herein by reference). However, Staphylococcal infections (such as pneumonia) can develop very rapidly in patients colonized with Staphylococcus aureus, so there is a need to identify at-risk patients who will benefit most from autoanti-AT antibodies. [Summary of the Invention] Staphylococcal pneumonia (S. aureus) is an early, life-threatening complication in mechanically ventilated intensive care unit (ICU) patients, regardless of infection control and antibiotics. As demonstrated in this article, the use of anti-alpha toxin (AT) antibodies for the prevention of S. aureus pneumonia was evaluated and showed to be associated with clinically meaningful efficacy (≥ 25% relative risk reduction) and acceptable safety. Specifically, a 32% reduction in S. aureus pneumonia was observed in patients receiving anti-AT antibodies without safety concerns. Furthermore, even greater efficacy was observed in certain subsets of patients. Therefore, this article provides a method for identifying patients at risk of developing S. aureus infection who will benefit from receiving anti-AT antibodies. This article provides a method for treating an individual colonized with Staphylococcus aureus (S. aureus), comprising administering to the individual an antibody or antigen-binding fragment bound to Staphylococcus aureus alpha toxin (AT), wherein the Staphylococcus aureus content in a sample obtained from the individual has been detected using polymerase chain reaction (PCR). In some instances, the sample obtained from the individual has a Staphylococcus aureus content not exceeding a Staphylococcus aureus content associated with a polymerase chain reaction (PCR) cycle limit (Ct) value. In some instances, this method reduces the incidence of infection associated with the presence of Staphylococcus aureus in the individual. This article provides a method for preventing Staphylococcus aureus infection in an individual, which includes administering to the individual an antibody or antigen-binding fragment bound to Staphylococcus aureus AT, wherein the sample obtained from the individual has a Staphylococcus aureus content not exceeding the Staphylococcus aureus content associated with the PCR Ct value. This article provides a method for reducing the incidence of Staphylococcus aureus pneumonia in an individual, which includes administering sulatumab to the individual, wherein the reduction is measured by clinical, microbiological and radiographic measures, and the incidence is reduced by approximately 30% depending on the circumstances. This article provides a method for reducing the incidence of all-cause pneumonia in an individual, which includes administering sulatumab to the individual, wherein the reduction is measured by clinical, microbiological and radiographic measures, and the incidence is reduced by approximately 30% depending on the circumstances. In some instances, the infection was determined by clinical, microbiological, and radiographic measurements. In some instances, the clinical measurement includes abnormal body temperature, abnormal white blood cell count, cough, purulent sputum, bronchial breath sounds, dyspnea, tachypnea (respiratory rate > 30 breaths / minute), hypoxemia, or any combination thereof. In some instances, the microbial assay includes respiratory samples, blood cultures, pleural effusion aspirates, or lung tissue cultures that are positive for Staphylococcus aureus. In some instances, the radiographic measurement includes the presence of new or worsening infiltrations on chest X-rays. In some instances, PCR was used to detect the Staphylococcus aureus content in samples obtained from the individual. In some instances, the sample obtained from the individual had a Staphylococcus aureus content not exceeding the Staphylococcus aureus content associated with the polymerase chain reaction (PCR) cycle limit (Ct) value. In some instances, the methods provided herein further include detecting the amount of Staphylococcus aureus in a sample obtained from the individual. In some instances, the sample obtained from the individual has a Staphylococcus aureus content not exceeding a PCR Ct value of 29 or higher. In some instances, the PCR Ct value of 29 corresponds to a concentration of approximately 1600 to approximately 1700 colony-forming units (CFU) / ml of Staphylococcus aureus. This article provides a method for treating an individual colonized with Staphylococcus aureus infection, comprising administering to the individual an antibody or antigen-binding fragment bound to Staphylococcus aureus AT, wherein the sample obtained from the individual has a concentration of Staphylococcus aureus not exceeding 1700 CFU / ml. In some instances, this method reduces the incidence of infection in the individual concomitant with the presence of Staphylococcus aureus. This article provides a method for preventing Staphylococcus aureus infection in an individual, which includes administering to the individual an antibody or antigen-binding fragment bound to Staphylococcus aureus AT, wherein the sample obtained from the individual has a concentration of no more than 1700 CFU / ml of Staphylococcus aureus. In some instances, the concentration of Staphylococcus aureus AT was measured using PCR. In some instances, the system was colonized with Staphylococcus aureus. In some instances, samples obtained from the individual had a Staphylococcus aureus content at least as correlated with the PCR Ct value. In some instances, samples obtained from the individual had a Staphylococcus aureus content at least as correlated with the PCR Ct value of 3. In some instances, the Staphylococcus aureus content was tested within 3 hours, or, depending on the circumstances, within 2 hours. In some instances, this PCR detects Staphylococcus aureus protein A. In some instances, the individual was ventilated, and in some cases, mechanically ventilated. In some instances, the individual was taking antibiotics. In some instances, the sample is a skin or soft tissue sample. In some instances, the sample is obtained from the individual's lower respiratory tract. In some instances, the sample is an endotracheal aspirate. In some instances, the sample is a tracheal sample. In some instances, the sample is a bronchial sample. In some instances, the sample contains bacteria that will not grow in the culture used to identify Staphylococcus aureus. In some instances, the sample contains non-staphylococcal bacteria. In some instances, the Staphylococcus aureus is antibiotic-resistant. In some instances, the method provided herein further includes determining whether the Staphylococcus aureus is antibiotic-resistant. In some instances, the *Staphylococcus aureus* strain is resistant to xylenepenicillin. In some instances, the method provided herein further includes determining whether the *Staphylococcus aureus* strain is resistant to xylenepenicillin. In some instances, this drug resistance was determined using PCR. In some instances, the infection is pneumonia. In some instances, the infection is intensive care unit (ICU) pneumonia. In some instances, the individual is human. In some instances, the antibody binding to Staphylococcus aureus AT or its antigen-binding fragment binds to the same Staphylococcus aureus AT antigenic determinant as antibodies comprising VH containing the amino acid sequence of SEQ ID NO:7 and VL containing the amino acid sequence of SEQ ID NO:8. In some instances, the antibody binding to Staphylococcus aureus AT or its antigen-binding fragment competitively inhibits the binding of antibodies comprising VH containing the amino acid sequence of SEQ ID NO:7 and VL containing the amino acid sequence of SEQ ID NO:8 to Staphylococcus aureus AT. In some instances, the antibody or antigen-binding fragment binding to Staphylococcus aureus AT comprises VH CDR1, VH CDR2, VH CDR3, VL CDR1, VL CDR2, and VL CDR3 of MEDI4893. In some instances, the antibody or antigen-binding fragment binding to Staphylococcus aureus AT comprises a variable heavy chain (VH) complementarity-determining region (CDR) 1 containing the amino acid sequence of SEQ ID NO:1, a VH CDR2 containing the amino acid sequence of SEQ ID NO:2, a VH CDR3 containing the amino acid sequence of SEQ ID NO:3, a variable light chain (VL) CDR1 containing the amino acid sequence of SEQ ID NO:4, a VL CDR2 containing the amino acid sequence of SEQ ID NO:5, and a VL CDR3 containing the amino acid sequence of SEQ ID NO:6. In some instances, the antibody or antigen-binding fragment that binds to Staphylococcus aureus AT comprises a VH containing the amino acid sequence of SEQ ID NO:7. In some instances, the antibody or antigen-binding fragment that binds to Staphylococcus aureus AT comprises a VL containing the amino acid sequence of SEQ ID NO:8. In some instances, the antibody or antigen-binding fragment that binds to Staphylococcus aureus AT comprises a heavy chain containing the amino acid sequence of SEQ ID NO:9. In some instances, the antibody or antigen-binding fragment that binds to Staphylococcus aureus AT comprises a light chain containing the amino acid sequence of SEQ ID NO:10. In some instances, the antibody or antigen-binding fragment binding to Staphylococcus aureus AT further comprises a heavy chain constant region. In some instances, the heavy chain constant region is selected from the group consisting of: human immunoglobulin IgG1, IgG2, IgG3, IgG4, IgA1, and IgA2 heavy chain constant regions. In some instances, the heavy chain constant region is the human IgG1 constant region. In some instances, the antibody or antigen-binding fragment binding to Staphylococcus aureus AT further comprises a light chain constant region. In some instances, the light chain constant region is selected from the group consisting of the light chain constant regions of human immunoglobulins IgGκ and IgGλ. In some instances, the light chain constant region is the human IgGκ light chain constant region. In some instances, the antibody or antigen-binding fragment that binds to Staphylococcus aureus AT is an IgG antibody or antigen-binding fragment thereof. In some instances, the antibody or antigen-binding fragment that binds to Staphylococcus aureus AT includes an Fc region that has been engineered to increase its half-life. In some instances, the antibody or antigen-binding fragment that binds to Staphylococcus aureus AT includes an Fc region with a YTE mutation. In some instances, the antibody or antigen-binding fragment that binds to Staphylococcus aureus AT is a monoclonal antibody or antigen-binding fragment. In some instances, the antibody or antigen-binding fragment binding to Staphylococcus aureus AT is a full-length antibody. In some instances, the antibody or antigen-binding fragment binding to Staphylococcus aureus AT is an antigen-binding fragment. In some instances, the antigen-binding fragment includes Fab, Fab', F(ab')2, single-chain Fv (scFv), disulfide-linked Fv, intrabody, IgGΔCH2, microantibody, F(ab')3, tetraantibody, triantibody, diantibody, DVD-Ig, Fcab, mAb2, (scFv)2, or scFv-Fc. In some instances, the antibody or its antigen-binding fragment that binds to Staphylococcus aureus AT has an affinity of 80 to 100 pM for Staphylococcus aureus AT. In some instances, the antibody or its antigen-binding fragment is a surutu monoclonal antibody. In some instances, 2000 mg of the antibody or antigen-binding fragment was administered. In some instances, 5000 mg of the antibody or antigen-binding fragment was administered. In some instances, the prevention of Staphylococcus aureus infection includes toxin neutralization, induction of opsonization, inhibition of thromboembolic lesion formation, inhibition of Staphylococcus aureus-associated sepsis, or any combination thereof. This article provides antibodies or antigen-binding fragments thereof that bind to Staphylococcus aureus AT for the treatment of individuals colonized with Staphylococcus aureus (S. aureus), wherein samples obtained from such individuals have a Staphylococcus aureus content not exceeding a value associated with the polymerase chain reaction (PCR) cycle limit (Ct). In some instances, this treatment reduces the incidence of infections associated with the presence of Staphylococcus aureus in the individual. This article provides an antibody or antigen-binding fragment thereof that binds to Staphylococcus aureus AT, for the prevention of Staphylococcus aureus infection in individuals colonized with Staphylococcus aureus, wherein the sample obtained from the individual has a Staphylococcus aureus content not exceeding the Staphylococcus aureus content associated with the PCR Ct value. In some instances, the sample obtained from the individual has a Staphylococcus aureus content not exceeding the PCR Ct value associated with 29. In some instances, if a Staphylococcus aureus content not exceeding the PCR Ct value associated with the individual is detected in the sample obtained from the individual, the antibody or its antigen-binding fragment will not be administered to the individual. This article provides an in vitro method for identifying an individual colonized with Staphylococcus aureus that responds to an antibody or antigen-binding fragment bound to Staphylococcus aureus AT. The method includes detecting the Staphylococcus aureus content in a sample obtained from the individual, wherein a Staphylococcus aureus content not exceeding a value correlated with a PCR Ct value indicates that the individual is responding to the antibody or antigen-binding fragment. In some instances, this PCR Ct value is 29.

Implementation Method

Claims

1. The use of an antibody or antigen-binding fragment thereof that binds to Staphylococcus aureus α-toxin (AT) for the preparation of a medicament for the treatment or prevention of Staphylococcus aureus infection in an individual colonized with Staphylococcus aureus, wherein the amount of Staphylococcus aureus in a sample obtained from the individual has been detected by polymerase chain reaction (PCR), and the sample has a Staphylococcus aureus content not exceeding a PCR cycle limit (Ct) value of 29, wherein the antibody or antigen-binding fragment thereof that binds to Staphylococcus aureus AT comprises: a variable heavy chain (VH) complementarity-determining region (CDR) 1 comprising the amino acid sequence of SEQ ID NO: 1, a VH CDR2 comprising the amino acid sequence of SEQ ID NO: 2, a VH CDR3 comprising the amino acid sequence of SEQ ID NO: 3, a variable light chain (VL) CDR1 comprising the amino acid sequence of SEQ ID NO: 4, and a CDR1 comprising the amino acid sequence of SEQ ID NO:

4. VL CDR2 containing the amino acid sequence of SEQ ID NO: 5, and VL CDR3 containing the amino acid sequence of SEQ ID NO: 6, wherein the PCR Ct value of the 29 corresponds to a sample concentration of Staphylococcus aureus of 1600 to 1700 colony-forming units (CFU) / ml.

2. As requested in claim 1, wherein the individual is identified as expected to benefit from the administration of the antibody or its antigen-binding fragment bound to Staphylococcus aureus AT.

3. As requested in item 1 or 2, wherein the PCR detects Staphylococcus aureus protein A.

4. As requested in item 1 or 2, wherein the antibiotic resistance of the Staphylococcus aureus strain is determined by PCR.

5. As claimed in claim 1 or 2, wherein the antibody or antigen-binding fragment thereof that binds to Staphylococcus aureus AT contains an Fc region having a YTE mutation.

6. As requested in item 1 or 2, wherein the antibody or antigen-binding fragment binding to Staphylococcus aureus AT is a monoclonal antibody or antigen-binding fragment.

7. As claimed in claim 1 or 2, wherein the antibody or antigen-binding fragment thereof that binds to Staphylococcus aureus AT has an affinity of 80 to 100 pM for Staphylococcus aureus AT.

8. As claimed in claim 1 or 2, wherein the antibody or antigen-binding fragment bound to Staphylococcus aureus AT comprises a variable heavy chain (VH) domain containing the amino acid sequence of SEQ ID NO:7 and a variable light chain (VL) domain containing the amino acid sequence of SEQ ID NO:

8.

9. As requested in claim 1 or 2, wherein the antibody or its antigen-binding fragment is suvratoxumab.

10. An in vitro method for identifying an individual colonized with Staphylococcus aureus who responds to an antibody or antigen-binding fragment bound to Staphylococcus aureus AT, the method comprising detecting the amount of Staphylococcus aureus in a sample obtained from the individual, wherein the amount of Staphylococcus aureus not exceeding a PCR Ct value of 29 indicates that the individual is responsive to the antibody or antigen-binding fragment thereof, wherein the antibody or antigen-binding fragment bound to Staphylococcus aureus AT comprises: a variable heavy chain (VH) complementarity-determining region (CDR) 1 comprising the amino acid sequence of SEQ ID NO: 1, a VH CDR2 comprising the amino acid sequence of SEQ ID NO: 2, a VH CDR3 comprising the amino acid sequence of SEQ ID NO: 3, a variable light chain (VL) CDR1 comprising the amino acid sequence of SEQ ID NO: 4, a VL CDR2 comprising the amino acid sequence of SEQ ID NO: 5, and a VL CDR2 comprising the amino acid sequence of SEQ ID NO:

6. CDR3, wherein the PCR Ct value of the 29 corresponds to a sample concentration of Staphylococcus aureus of 1600 to 1700 colony-forming units (CFU) / ml.

11. The method of claim 10, wherein the antibody or antigen-binding fragment thereof that binds to Staphylococcus aureus AT comprises a variable heavy chain (VH) domain containing the amino acid sequence of SEQ ID NO:7 and a variable light chain (VL) domain containing the amino acid sequence of SEQ ID NO:8, and wherein the antibody or antigen-binding fragment thereof comprises an Fc region having a YTE mutation.

12. The method of claim 10 or 11, wherein the antibody or its antigen-binding fragment is a suratu monoclonal antibody.

13. As requested in item 8, wherein the sample obtained from the individual is an endotracheal extract.

14. As claimed in claim 8, wherein the sample obtained from the individual is a skin or soft tissue specimen.

15. As requested in claim 9, wherein the sample obtained from the individual is an endotracheal extract.

16. As claimed in claim 9, wherein the sample obtained from the individual is a skin or soft tissue specimen.

Images