CLARITHROMYCIN TO PREVENT SECONDARY INFECTIONS IN PATIENTS WITH SEPSIS FOLLOWING LOWER RESPIRATORY TRACT INFECTIONS: THE CLASSIFY TRIAL

The goal of this clinical trial is to assess whether clarithromycin, given as an adjunct to standard-of-care antibiotic therapy, can reduce the risk of new infections and secondary sepsis in adult patients hospitalized with community-acquired pneumonia (CAP), sepsis, and sepsis-induced immunoparalysis (SII). The primary objective is to evaluate the effect of clarithromycin on the incidence of new infection, including worsening or recurrence of the initial CAP episode, new infections at other sites, and secondary sepsis during the 28-day follow-up period. Secondary objectives are to investigate the impact of clarithromycin on mortality, sepsis response, type of secondary infection, time to antimicrobial escalation, hospital readmission, quality of life, cost-effectiveness, and biomarkers of sepsis-induced immunoparalysis. Researchers will compare clarithromycin plus standard-of-care antibiotic therapy to placebo plus standard-of-care antibiotic therapy. Participants will: * Receive clarithromycin or placebo, administered orally or intravenously, in addition to standard-of-care antibiotic therapy for up to 7 days. * Be evaluated during treatment and follow-up through Day 28, with additional assessment of mortality, hospital readmission, and health status through Day 90.

Inclusion Criteria: * Age equal to or above 18 years * Patients of either gender * Written informed consent provided by the patient. For patients without decision-making capacity, informed consent must be obtained from a legally designated representative following the national legislation. * Negative (blood or urinary) pregnancy test for female patients of reproductive age * For female patients of reproductive age, willingness to use highly effective contraception during and seven days after the administration of the IMP. * Presence of Community-acquired pneumonia (CAP) * Presence of sepsis as defined by the Sepsis-3 classification criteria (at least 2 points increase of the total SOFA-1 score from the baseline score of the specific patient). The SOFA score which will be used for the definition of sepsis has recently been renamed SOFA-1. * Absolute lymphocyte count (ALC) less than 1000/mm³. Exclusion Criteria: * Age below 18 years * Denial of written informed consent * Pregnancy (confirmed by blood or urinary pregnancy test) or lactation for female patients * Unwillingness to receive contraception during and seven days after the administration of the IMPstudy drug (for Female patients) * Known HIV infection with known CD4 cell count \