COVID-19 seriously affected the study execution as required by the protocol

The purpose of this study is to assess the efficacy and safety of delafloxacin administered as IV and oral formulation in comparison with Best Available Therapy (BAT) in patients with superficial or deep incisional surgical site infection following a cardiothoracic/related leg or abdominal surgery.

This is a randomized, observer-blinded, active-controlled, parallel-group, multicenter, phase IIIb study for the treatment of incisional, superficial or deep, surgical site infection after cardiothoracic /related leg or abdominal surgery (i.e patients who are at risk of microbiologically resistant infections). IV to be switched to oral delafloxacin will be compared to treatments that represent the best available therapy (BAT) for either cardiothoracic/related leg or abdominal surgical site infection (SSI).

Approximately 600 male and female eligible patients will be randomly assigned in a 1:1 ratio to receive delafloxacin or BAT. For patients who are randomised to BAT, the investigator will choose one out of two treatments available (two available for the cardiothoracic/related leg and two available for abdominal SSI) as most appropriate for patient characteristics and local epidemiological pattern.

Duration of study depends on treatment duration (range: minimum 5 to maximum 14 days, as per Investigator's judgment) followed by visits up to 30 days after end of treatment.

Patients will be hospitalized from Screening (within 30 days from surgery) and will remain hospitalized until considered improved or cure as per Investigator's judgment.

Inclusion Criteria:

• Male or female patients aged more than 18 years.
• Patients with a history of cardiothoracic / related leg or abdominal surgery, occurred within 30 days and no implant is left in place, and a diagnosis of superficial or deep SSI according to the CDC definition.
• The severity of infection requires an IV treatment and patient hospitalization according to the Investigator's judgment.

Exclusion Criteria:

• Previous IV antimicrobial therapy exceeding 24-hour duration during 72 hours prior to first dose.
• Any infection expected to require systemic antimicrobial agents other than study treatment(s).
• Medical history of significant hypersensitivity or allergic reaction or contraindication to the study drugs
• Medical history of central nervous system (CNS) disorders
• Medical history of myasthenia gravis.
• Medical history of C. difficile diarrhea.
• Organ-space infection.
• Complicated Intra-Abdominal Infection (cIAI)
• Chronic or underlying conditions at site of infection that may complicate the assessment of clinical response or would interfere with SSI healing.
• Underlying disease leading to deep immunosuppressive status.
• End-stage renal disease, CrCl <15 mL/min.

ITT analysis population used as reference

Adverse events were collected for each participant from the time of ICF signature (Screening) up to to LPLV, i.e. for maximum 45 days.

Only the blinded observer will be unaware of the treatment assigned to patient.