Infective endocarditis (IE) is a serious infection with a significant burden for patients and hospitals (in France, median length of hospital stay = 43 days), partly due to the long duration of intravenous (IV) antibacterial treatment recommended by international guidelines, between 4 and 6 weeks in most situations.

A recent survey of practices regarding the management of IE in France showed that a switch from IV to oral antibiotics is feasible, when patients with left-sided Streptococcus-Enterococcus IE are stable after an initial course of IV antibiotic treatment, with or without valvular surgery.

These practices have not been associated with unfavourable outcome, while significantly reducing the duration and cost of hospitalization, the risk of nosocomial infection, and patients' discomfort.

There has been no randomized controlled trial (RCT) in the field of IE over the last 20 years; current guidelines are mostly based on expert advice, in vitro studies, animal experiments, or clinical studies performed before the 90's.

The RODEO 2 project is an unprecedented opportunity to bring back evidence-based medicine in the field of IE.

Most experts acknowledge that the pharmacological PK/PD characteristics of antibiotics such as amoxicillin allow a high level of efficacy in the treatment of IE when orally administrated after an IV period of induction.

It's needed to conduct RCTs that clearly demonstrate the clinical non-inferiority of this strategy for streptococci, and enterococci IE with a benefit regarding costs.

The RODEO 2 project corresponds to one pragmatic trial assessing the impact of a switch strategy, making it a comparative effectiveness trial that should be able to feed the next revision of IE international guidelines and to change practices in IE management.

The RODEO 2 study is designed to determine the safety and efficacy of partial oral treatment of IE compared with traditional full-length parenteral treatment. Our primary objective is to demonstrate that in patients with left-sided multi-susceptible Streptococcus-Enterococcus IE who have received at least 10 days of IV antibiotic treatment with or without valvular surgery, a switch to an oral combination of amoxicillin between Day 10 and Day 28 after initiation of the IV antibiotic treatment, is not inferior to the continuation of the conventional IV antibiotic treatment regarding to treatment failure within 3 months after the end of antibiotic treatment.

Nationwide, noninferiority, multicenter, randomized, controlled, open-label trials.

Randomisation will only be offered to patients who have received at least 10 days of IV conventional antibiotic treatment of IE, and fulfil the inclusion criteria.

Randomisation will take place between Day 10 and Day 28 after initiation of parenteral antibiotic therapy or valvular surgery, thus ensuring to have at least 14 days of oral therapy in the experimental group.

Patients will be eligible whether they have undergone valvular surgery or not. This will imply that surgery procedure prior to randomisation will be heterogeneous, but randomisation will be stratified on the requirement of valvular surgery as part of the treatment of the current episode of IE or not.

Inclusion Criteria:

• Left-sided IE (Defined according to Duke criteria) on native or prosthetic valve
• due to one isolate of Streptococcus/Enterococcus sp. susceptible to amoxicillin (MCI ≤ 0.5 mg/l)
• in an adult ≥18 year old
• appropriate parenteral antibiotics treatment received for at least 10 days
• in case of valvular surgery, appropriate parenteral antibiotics treatment received for at least 10 days after valvular surgery
• planned duration of antibiotics will extend for at least 14 days at the time of randomisation i.e. a potential switch to oral treatment between Day 10 and Day 28 thus ensuring to have at least 14 days of oral therapy remaining in the experimental group
• apyrexia (temperature < 38°C) at each time point during the last 48 hours (at least two measures/day) at the time of randomisation
• blood cultures have been sterile for at least 5 days at the time of randomisation
• informed, written consent obtained from patient
• subject covered by or having the rights to French social security

Exclusion Criteria:

• body mass index <15 kg/m² or > 40 kg/m²
• glomerular filtration rate < 30 ml/min/1,73m²
• patient unable or unwilling to take oral treatment (digestive intolerance, significant malabsorption) at the time of randomisation
• expected difficulties regarding compliance with oral antibiotic treatment or follow-up (e.g. severe cognitive impairment, severe psychiatric disease...)
• patient without entourage to support and watch him at discharge
• valvular surgery planned within the next 6 months
• for patients with cardiac devices (pace-maker, implantable cardiac defibrillator) and suspected device-related IE (vegetation on the leads) if removal of the device was not performed
• breast feeding or pregnant women, or women on childbearing age without effective contraception
• expected duration of follow-up < 7 months at the time of randomisation (e.g. expected life expectancy < 7 months, patient living abroad...)
• past medical history of IE in the last 3 months
• other infection requiring parenteral antibiotic therapy
• taking of an estrogen-progesterone treatment interacting with rifampicin
• patient with contra-indication to oral antibiotics administered in the experimental arm (i.e. amoxicillin) - including anticipated non-manageable drug interactions, and allergy.

There are no plans to grant public access to the full protocol, participant-level data or statistical code. Data from the RODEO trials is stored by the promotor of the trial. Data and the personal identifiers are stored separately and a special permit is required for access to the data. Data can be available on request for academic researchers when it have been analysed and published. Qualified researchers can ask for data sharing by the first author LB after the study finalization.

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After publication of the main manuscript