Staphylococcus Aureus Network Adaptive Platform Trial (SNAP)

University of Melbourne

Status and phase: Enrolling; Phase 4

Conditions: Staphylococcus Aureus Bacteremia

Treatments: Other: Effectiveness of early switch to oral antibiotics; Drug: Vancomycin; Drug: Cefazolin; Drug: Clindamycin; Drug: Penicillin; Radiation: Whole body FDG PET/CT Imaging

Study type: Interventional

Funder types: Other

Identifiers

NCT05137119

CT19029

Details and patient eligibility

About

The Staphylococcus aureus Network Adaptive Platform (SNAP) trial is an International Multi-Centered Randomised Adaptive Platform Clinical Trial to evaluate a range of interventions to reduce mortality for patients with Staphylococcus Aureus bacteraemia (SAB).

Full description

Infection of the bloodstream with the bacterium Staphylococcus aureus (Staphylococcus aureus bacteraemia, SAB) is a serious infection that results in 15-30% of affected patients dying within three months of acquiring the infection. Treatment of this infection requires patients to be hospitalised, treated with prolonged antibiotics through an intravenous line, and carefully examined for the occurrence of complications associated with this condition. At present, there are many treatment options in current use, with no clear agreement as to which of these is best. The SNAP trial aims to identify which treatment options for SAB results in the fewest patients dying within the first 90 days after an infection.

In contrast to a conventional clinical trial, the SNAP trial will examine multiple different treatment options at once. Patients will be randomly assigned to different concurrent treatment options currently considered acceptable in routine medical care, but as the trial progresses, more patients will be assigned to treatments that appear to have better outcomes than those with worse outcomes. The trial will adapt to accumulating trial evidence, on a regular basis, by removing treatment options found to be inferior, incorporating new treatment options, and ensuring that all patients in the trial receive the best treatments once they have been identified. Over time, we hope to determine the best combination of treatment options for patients with SAB.

The SNAP Trial infrastructure will also support a number of sub-studies. A list of all active sub-studies can be found on the SNAP website: https://www.snaptrial.com.au/substudies.

Enrollment: 8,000 estimated patients

Sex: All

Volunteers: No Healthy Volunteers

Inclusion and exclusion criteria

PLATFORM Inclusion Criteria:

Patients must fulfil all of the following criteria to be eligible to enter the SNAP trial:

1. Staphylococcus aureus complex grown from ≥1 blood culture
2. Admitted to a participating hospital at the time of eligibility assessment

PLATFORM Exclusion Criteria:

Potentially eligible participants meeting any of the following criteria at the time of eligibility assessment for platform entry will be excluded from the trial:

1. Time of anticipated platform entry is greater than 72 hours post collection of the index blood culture. Where the time of culture collection is not recorded, the time of laboratory registration of the sample will be used as an alternative
2. Polymicrobial bacteraemia, defined as more than one organism (at species level) in the index blood cultures OR in any subsequent blood culture reported between the collection of the index blood culture and platform eligibility assessment, excluding those organisms judged to be contaminants by either the microbiology laboratory or treating clinician.
3. Known previous participation in the randomised SNAP platform
4. Known positive blood culture for S. aureus (of the same silo: PSSA, MSSA or MRSA) between 72 hours and 180 days prior to the time of eligibility assessment
5. Treating team deems enrolment in the study is not in the best interest of the patient
6. Treating team believes that death is imminent and inevitable
7. Patient is for end-of-life care and antibiotic treatment is considered not appropriate
8. Patient <18 years of age and paediatric recruitment not approved at recruiting site
9. Patient has died since the collection of the index blood culture

To be included in any of the following DOMAINS the participant must met eligible for the PLATFORM (as listed above)

ADJUNCTIVE TREATMENT DOMAIN

Inclusion Criteria:

1. All participants that met the PLATFORM eligible are eligible to be included in this domain unless they meet any of the following exclusions listed.

2. Patients are eligible for this domain regardless of S. aureus susceptibility testing results to clindamycin.

   Exclusion criteria:

3. Previous type 1 hypersensitivity reaction to lincosamides 2. Currently receiving clindamycin (lincomycin) or linezolid which cannot be ceased or substituted 3. Necrotising fasciitis 4. Current C. difficile associated diarrhoea (any severity) 5. Current severe diarrhoea from any cause (defined as Grade 3 or higher) 5. Known CDAD (C.Difficile Associated Diarrhoea) in the past 3 months, or CDAD relapse in the past 12 months 6. At the time of domain eligibility assessment, more than 4 hours has elapsed since platform entry 7. Treating clinician deems enrolment in this domain is not in the best interest of the patient

PSSA, MSSA TREATMENT DOMAIN (backbone)

Inclusion Criteria:

1. For PSSA silo: Index blood culture is penicillin-susceptible as per phenotypic disc testing with EUCAST (a P1 disc diffusion with a feathered zone >=26mm) OR CLSI (a P10 disc diffusion) defined criteria
2. For MSSA silo: Index blood culture isolate is methicillin-susceptible but penicillin resistant

Exclusion Criteria (PSSA & MSSA):

1. >72 hours have elapsed since the collection of the index blood culture (i.e. the time of collection of the first positive blood culture from the patient during this episode)
2. History of type I hypersensitivity reaction (i.e. anaphylaxis or angioedema) to any penicillin or cephalosporin
3. History of severe delayed reaction (e.g. allergic interstitial nephritis, cutaneous vasculitis, Stevens-Johnson, DRESS, etc.) to any penicillin or cephalosporin
4. PSSA silo: Non-severe rash to any penicillin (unless patient has been subsequently de-labelled; this criteria does not include criteria 2 and 3 above), or MSSA silo: Non-severe rash to cefazolin or any penicillin (unless patient has been subsequently de-labelled) (Nausea, diarrhoea, headache, and other non-specific symptoms are NOT allergies, they are drug intolerance, and they are not exclusion criteria. Similarly, a vague history of an allergy of unclear nature, or a family history of allergy are not exclusions.)
5. Treating team deems enrolment in this domain is not in the best interest of the patient
6. Currently receiving maintenance dialysis (haemodialysis or peritoneal dialysis) (Acute renal replacement therapy (including CRRT, haemodialysis or peritoneal dialysis) are not exclusions. Such patients are eligible as long as appropriate vascular access is available or can be arranged.)
7. Polymicrobial bacteraemia (defined as more than one organism [at species level] in blood cultures, excluding those organisms judged to be contaminants by either the microbiology laboratory or treating clinician) reported between collection of the index blood culture and backbone domain eligibility assessment
8. Patient currently being treated with a systemic antibacterial agent that cannot be ceased or substituted for interventions allocated within the platform (unless antibiotic is listed in Table 1 of the DSA, which specifies allowed antibiotics with limited absorption from the gastrointestinal tract or negligible antimicrobial activity against S. aureus)

MRSA TREATMENT DOMAIN (backbone)

Inclusion Criteria:

1. MRSA confirmed microbiologically

Exclusion Criteria:

1. Time to allocation reveal is >72 hours from time of index blood culture collection

2. Severe allergy to any beta-lactam (including cefazolin) Immediate severe allergy: Anaphylaxis/angioedema Severe delayed allergy: Severe cutaneous adverse reaction (SCAR; including Steven Johnson Syndrome, Toxic Epidermal Necrolysis, Drug Rash with Eosinophilia and Systemic Symptoms (DRESS) and acute generalised exanthematous pustulosis (AGEP)), severe drug induced liver injury, proven allergic interstitial nephritis, immune-mediated haemolytic anaemia and other severe cytopenia.

3. Non-severe rash to cefazolin Nausea, diarrhoea, headache and other non-specific symptoms are NOT allergies, they are drug intolerance, and they are not exclusion criteria. Similarly, a vague history of an allergy of unclear nature, or a family history of allergy are not exclusions.)

4. Severe allergy or non-severe rash to both vancomycin AND daptomycin Vancomycin infusion reaction (formerly known as "red man syndrome") is due to direct histamine release and is not generally an allergy, and therefore is not considered an exclusion.

5. Treating team deems enrolment in the domain is not in the best interest of the patient 6. Polymicrobial bacteraemia (defined as more than one organism [at species level] in blood cultures, excluding those organisms judged to be contaminants by either the microbiology laboratory or treating clinician) reported between collection of the index blood culture and backbone domain eligibility assessment.

6. Patient currently being treated with a systemic antibacterial agent that cannot be ceased or substituted for interventions allocated within the platform (unless antibiotic is listed in Table 1 of the DSA, which specifies allowed antibiotics with limited absorption from the gastrointestinal tract or negligible antimicrobial activity against S. aureus)

EARLY ORAL SWITCH DOMAIN

Inclusion Criteria:

Day 7 (+/- 2 days):

1. Clearance of SAB by platform Day 2: blood cultures negative for S. aureus from platform Day 2 onwards AND no known subsequent positive blood cultures
2. Afebrile (<37.8°C) for the past 72 hours (at time of judging eligibility)
3. Primary focus is either line related (either central or peripheral IV cannula) or skin and soft tissue, AND source control achieved (for 'line-related' this means line removed; for 'skin and soft tissue' means site PI considers source control to have been achieved and any abscess more than 2cm diameter has been drained)
4. No evidence of metastatic foci (on clinical or radiological examination, but radiological imaging is not required to exclude metastatic foci if not clinically indicated)

Day 14 (+/- 2 days):

1. Clearance of SAB by platform Day 5: blood cultures negative for S. aureus from platform Day 5 (+/-1 day) AND no known subsequent positive blood cultures. If the most recent blood culture from Day 2-4 is negative for S. aureus, blood cultures do not need to be repeated on Day 5 to fulfil eligibility criteria (Day 5 blood cultures will be assumed to be negative in this situation)
2. Afebrile (<37.8°C) for the past 72 hours (at time of judging eligibility)
3. Site Principal Investigator has determined that source control is adequate

Exclusion Criteria:

When judging eligibility at platform Day 7 (+/- 2 days) and at Day 14 (+/- 2 days), exclusion criteria are:

1. Adherence to oral agents unlikely (as judged by site PI in consultation with the treating team)
2. Unreliable gastrointestinal absorption (e.g. vomiting, diarrhoea, nil by mouth, anatomical reasons)
3. There are no appropriate oral antibiotics due to contraindications, drug availability, or antibiotic resistance
4. Ongoing IV therapy unsuitable e.g. no IV access
5. Clinician deems not appropriate for early oral switch
6. Patient no longer willing to participate in domain In the lead-up to judging eligibility, it may be helpful to discuss with the patient the potential for continued IV treatment versus oral switch, to allow hospital discharge planning
7. Clinical team deems that sufficient duration of antibiotic therapy has already been provided

Exclusions when judging eligibility for early oral switch at trial Day 7 (+/- 2 days):

1. Presence of prosthetic cardiac valve, pacemaker or other intracardiac implant
2. Presence of intravascular clot, graft, or other intravascular prosthetic material Intravascular clot excludes superficial peripheral IV line-related thrombophlebitis. Intravascular prosthetic material excludes coronary artery stents)
3. Intravascular/intracardiac infections (e.g. endocarditis, mycotic aneurysm)
4. Presence of other intracardiac abnormalities felt to put patient at increased risk of endocarditis (e.g., bicuspid aortic valve)

PET/CT DOMAIN

Inclusion Criteria:

1. PET/CT participating site
2. Patient is accessible for PET/CT - a patient is considered accessible if the site team are able to access the participant medical records, arrange for a PET/CT scan for the patient, and discuss this domain with the patient and their treating healthcare providers.

Exclusion Criteria:

1. Pregnant - patients of childbearing potential should be assessed for pregnancy status and a pregnancy test performed (if not performed within the past 10 days)
2. Currently breastfeeding
3. < 18 years of age
4. Patient has had PET/CT in the past 7 days
5. Patient needs PET/CT in the next 7 days (in the opinion of the clinical team, at the time of eligibility assessment)
6. Clinically unstable for PET/CT (as judged by the treating clinical team, taking into account need for organ support (including inotropes) and capacity to lie flat for the PET/CT)
7. Contraindication to PET/CT (e.g., claustrophobia, persistently elevated blood sugar levels [>12.5mmol/L] that cannot be corrected).
8. Patient no longer willing to participate in the domain - in the days leading up to judging eligibility, it may be helpful to discuss with the patient the potential for PET/CT vs no PET/CT to allow imaging planning
9. Clinician deems participation in this domain is not in the patient's best interests

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Factorial Assignment

Masking: None (Open label)

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8,000 participants in 12 patient groups

Methicillin-resistant staphylococcus aureus (MRSA) - Standard Therapy Arm (backbone therapy)

No Intervention group

Description:

Vancomycin or Daptomycin - Standard Therapy Arm Either intravenous vancomycin dosed as per Australian Therapeutic Guidelines: This includes a loading dose of 25 mg/kg (up to 3000mg) if considered appropriate by the treating clinician, initial maintenance dosing at 15-20 mg/kg q12h, with subsequent adjustment to maintain area under the concentration-time curve (AUC) of 400 to 600 mg.hr/L OR trough levels at 10-20 mg/L, and the initial level taken 48-72 hours after the initiation of the first dose. Daptomycin 8-10mg/kg per day intravenously. The choice of vancomycin or daptomycin will be at the clinician's discretion. Dosing will be based on renal function.

Methicillin-resistant staphylococcus aureus (MRSA) - Standard + B-Lactam Arm (backbone therapy)

Experimental group

Description:

Vancomycin or Daptomycin (Standard Therapy) + Beta-Lactam (β-lactam) Arm In addition to standard treatment an intravenous β-lactam will be added for the first 7 calendar days following randomisation (day 1 being the day of randomisation - hence patients will receive 6-7 days of β-lactam). This β-lactam will be intravenous cefazolin 2g every 8 hours. For patients with renal impairment the intravenous cefazolin administration doses will be adjusted.

Treatment:

Drug: Cefazolin

Drug: Vancomycin

Methicillin-susceptible staphylococcus aureus (MSSA) - Standard Therapy Arm (backbone therapy)

No Intervention group

Description:

Flucloxacillin or cloxacillin - Standard Therapy Arm Either intravenous flucloxacillin/cloxacillin 2g every 4 or 6 hours. The minimum protocol duration of allocated study treatment is 14 days for those not allocated to early oral switch, and 5 days for those allocated to early oral switch. For patients with renal impairment or critical illness the intravenous flucloxacillin administration dose will be adjusted.

Methicillin-susceptible staphylococcus aureus (MSSA) - Interventional Arm (backbone therapy)

Experimental group

Description:

Cefazolin - Interventional Arm Intravenous cefazolin 2g every 6 or 8 hours. The minimum protocol duration of allocated study treatment is 14 days for those not allocated to early oral switch, and 5 days for those allocated to early oral switch. For patients with renal impairment or critical illness the intravenous cefazolin administration dose will be adjusted.

Treatment:

Drug: Cefazolin

Penicillin-susceptible staphylococcus aureus (PSSA) - Standard Therapy Arm (backbone therapy)

No Intervention group

Description:

Flucloxacillin or cloxacillin - Standard Therapy Arm Either intravenous flucloxacillin/cloxacillin 2g every 4 or 6 hours. The minimum protocol duration of allocated study treatment is 14 days for those not allocated to early oral switch, and 5 days for those allocated to early oral switch. For patients with renal impairment or critical illness the intravenous flucloxacillin administration dose will be adjusted.

Penicillin-susceptible staphylococcus aureus (PSSA) - Interventional Arm (backbone therapy)

Experimental group

Description:

Benzylpenicillin - Interventional Arm Intravenous benzylpenicillin 1.8g (3 million units) every 4 or 6 hours. The minimum protocol duration of allocated study treatment is 14 days for those not allocated to early oral switch, and 5 days for those allocated to early oral switch. For patients with critical illness the intravenous benzylpenicillin administration doses will be adjusted.

Treatment:

Drug: Penicillin

No adjunctive treatment in combination with MRSA or MSSA or PSSA backbone therapy arm

No Intervention group

Description:

No adjunctive therapy + backbone therapy arm for MRSA or MSSA or PSSA Participants with either MRSA or MSSA or PSSA will have no adjunctive therapy in combination with their backbone therapy arm.

Adjunctive treatment in combination with MRSA or MSSA or PSSA backbone therapy arm

Experimental group

Description:

Adjunctive therapy + backbone therapy arm for MRSA or MSSA or PSSA Intravenous clindamycin (or lincomycin) 600mg every 8 hours from platform day 1 to day 5. No dosage adjustment is needed to renal impairment.

Treatment:

Drug: Clindamycin

Continue intravenous antibiotic therapies (backbone +/- adjunctive therapy) - standard of care arm

No Intervention group

Description:

Backbone therapy arm for MRSA or MSSA or PSSA +/- adjunctive therapy will continue on intravenous antibiotic treatment for the length of time as per usual standard of care. Participants eligibility is assessed at Day 7 (+/- 2 days) if eligible will be randomised if not eligible then eligibility will be assess again at Day 14(+/- 2 days). If eligibility is not met at day 14 then participant is excluded from this domain.

Switch to oral antibiotics at trial day 7 (+/- 2 days) or Day 14 (+/- 2 days) if eligible.

Experimental group

Description:

Switch from intravenous backbone antibiotic for MRSA or MSSA or PSSA to oral antibiotics at the treating clinicians discretion on trial Day 7 (+/- 2 days) or trial Day 14 (+/- 2 days). Participants eligibility is assessed at Day 7 (+/- 2 days). If eligible will be randomised, if not eligible then eligibility will be assessed again at Day 14 (+/- 2 days). If eligibility is not met at day 14 then participant is excluded from this domain.

Treatment:

Other: Effectiveness of early switch to oral antibiotics

No PET/CT scan - standard of care arm

No Intervention group

Description:

Participants will not receive a PET/CT scan, in addition to their allocated treatment interventions. Participants eligibility is assessed at Day 7 (+/- 2 days) if eligible will be randomised. If eligibility is not met then participant is excluded from this domain.

PET/CT scan at trial day 7 (+/- 2 days) if eligible

Experimental group

Description:

Participant will receive a PET/CT scan at Day 5-12, in addition to their allocated treatment interventions. Participants eligibility is assessed at Day 7 (+/- 2 days) if eligible will be randomised. If eligibility is not met then participant is excluded from this domain.

Treatment:

Radiation: Whole body FDG PET/CT Imaging