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Omadacycline is novel, aminomethyl tetracycline antibiotic being developed for oral and intravenous (IV) administration for the treatment of community-acquired bacterial infections. Omadacycline is characterized by an aminomethyl substituent at the C9 position of the core 6-member ring. Modifications at this position result in an improved spectrum of antimicrobial activity by overcoming resistance known to affect older generation tetracyclines via ribosomal protection proteins and efflux pump mechanisms. In vitro, omadacycline has activity against Gram-positive and Gram-negative aerobes, anaerobes, and atypical pathogens including Legionella and Chlamydia spp. Omadacycline offers once daily oral and IV dosing and a clinical tolerability and safety profile that compares favorably with contemporary antibiotics used across serious community-acquired infections where resistance has rendered many less effective. In studies in patients with complicated skin and skin structure infections, including those with MRSA infections, omadacycline exhibited an efficacy and tolerability profile that was comparable to linezolid. Ongoing and planned clinical studies are evaluating omadacycline as monotherapy for treating serious community-acquired bacterial infections including Acute Bacterial Skin and Skin Structure Infections (ABSSSI) and Community-Acquired Bacterial Pneumonia (CABP). This review provides an overview of the discovery, microbiology, nonclinical data, and available clinical safety and efficacy data for omadacycline, with reference to other contemporary tetracycline-derived antibiotics. [ABSTRACT FROM AUTHOR]

Summary: Background: Available drugs against cytomegalovirus have adverse effects that compromise their prophylactic use in recipients of allogeneic stem-cell transplants. We assessed the safety, tolerability, and antiviral activity of oral maribavir in such patients. Methods: In this placebo-controlled, randomised, double-blind, multicentre phase 3 study, we enrolled adult patients recipient-seropositive or donor-seropositive for cytomegalovirus who had undergone allogeneic stem-cell transplantation. Patients were recruited from 90 centres in Canada, Europe, and the USA. After engraftment, patients were stratified by recipient cytomegalovirus serostatus and conditioning regimen (myeloablative or reduced-intensity) and assigned (2:1) by masked computer-generated randomisation sequence to receive maribavir 100 mg twice daily or placebo for up to 12 weeks, with weekly blood cytomegalovirus surveillance. If the virus was detected, administration of study drug was stopped and pre-emptive anticytomegalovirus treatment started. The primary endpoint was cytomegalovirus disease within 6 months of transplantation. Analysis was by intention-to-treat. This study is registered with ClinicalTrials.gov, NCT00411645. Findings: Between December, 2006, and May, 2008, 681 patients were enrolled and assigned to receive maribavir (454) or placebo (227). The incidence of cytomegalovirus disease within 6 months was 20 of 454 (4%) for the maribavir group and 11 of 227 (5%) for the placebo group (OR 0·90; 95% CI 0·42–1·92). During the 100 days following transplantation, cytomegalovirus infection rates as measured by pp65 antigenaemia were lower in the maribavir group (26·4%) than in the placebo group (34·8%; OR 0·67; 0·47–0·95), but not when measured by plasma cytomegalovirus DNA PCR (27·8%vs 30·4%; OR 0·88; 0·62–1·25), nor by initiation of treatment against cytomegalovirus (30·6%vs 37·4%; OR 0·73, 0·52–1·03). Maribavir was well tolerated: most adverse events, including incident acute graft-versus-host disease and neutropenia, affected both groups equally, except for taste disturbance (15% maribavir, 6% placebo). Interpretation: Compared with placebo, maribavir prophylaxis did not prevent cytomegalovirus disease when started after engraftment. Cytomegalovirus disease as a primary endpoint might not be sufficient to show improvements in cytomegalovirus prevention in recipients of allogeneic stem-cell transplants in the setting of pre-emptive antiviral treatment. Clinical and virological composite endpoints should be used in future trials. Funding: ViroPharma Incorporated. [Copyright &y& Elsevier]