Clinical Efficacy of Patients With Secondary Bacteremia Treated With Omadacycline: Results From Phase 3 Acute Bacterial Skin and Skin Structure Infections and Community-Acquired Bacterial Pneumonia Studies

Evaluation of omadacycline dosing regimens in Chinese using population pharmacokinetic-pharmacodynamic analysis

PURPOSE

Omadacycline (PTK-0796) is a first-in-class aminomethylcycline for adult patients with community-acquired bacterial pneumonia (CABP) and acute bacterial skin and skin structure infections (ABSSSI) caused by susceptible pathogens. We investigated the pharmacokinetic (PK) and pharmacodynamic (PD) profile of omadacycline, considering the impact of covariates, particularly ethnicity, on PK and determined the PK/PD cutoff values for dosing regimens.

METHODS

Utilizing nonlinear mixed-effects modeling, we pooled data from 11 clinical trials for PopPK analysis. The first-order conditional estimation with interaction (FOCEI) method in NONMEM facilitated model parameter estimation. Employing a stepwise model selection strategy, with forward addition (P < 0.01) and backward deletion (P < 0.001), we assessed the potential impacts of covariates on omadacycline PK, including baseline age, body weight, sex, race, body mass index, body surface area, baseline albumin, creatine clearance, and formulation. After validating the model through various methods, the final PopPK model underwent Monte Carlo simulations to generate the PK profile for the Chinese population. This enabled AUC calculation and assessment of the probability of target attainment (PTA) and the cumulative fraction of response (CFR) for various dosing regimens and bacterial strains.

RESULTS

Omadacycline's PK can be adequately characterized by a three-compartment model. Body weight, sex, race, and drug formulation statistically influenced its PK. Asians and non-Asians exhibit similar exposure after intravenous infusion, but oral dosing results in much higher exposures than in non-Asians. Monte Carlo simulation indicates that IV-only or IV/PO sequential therapy regimens provide adequate attainment for all major pathogens causing ABSSSI and CABP. PK/PD cutoffs were generally above the MIC90 value of recent clinical isolates from China.

CONCLUSIONS

In conclusion, the approved regimen for China achieved adequate target attainment for all pathogens typically associated with these infections. The higher oral exposure observed in Asians may enhance efficacy without affecting safety or tolerability.

Therapeutics for Vancomycin-Resistant Enterococcal Bloodstream Infections

Vancomycin-resistant enterococci (VRE) are common causes of bloodstream infections (BSIs) with high morbidity and mortality rates. They are pathogens of global concern with a limited treatment pipeline. Significant challenges exist in the management of VRE BSI, including drug dosing, the emergence of resistance, and the optimal treatment for persistent bacteremia and infective endocarditis. Therapeutic drug monitoring (TDM) for antimicrobial therapy is evolving for VRE-active agents; however, there are significant gaps in the literature for predicting antimicrobial efficacy for VRE BSIs. To date, TDM has the greatest evidence for predicting drug toxicity for the three main VRE-active antimicrobial agents daptomycin, linezolid, and teicoplanin. This article presents an overview of the treatment options for VRE BSIs, the role of antimicrobial dose optimization through TDM in supporting clinical infection management, and challenges and perspectives for the future.

Omadacycline in treating community-based infections: a review and expert perspective

INTRODUCTION

Omadacycline is approved for the treatment of community-acquired bacterial pneumonia (CABP) and acute bacterial skin and soft tissue infection (ABSSSI). The integration of newer agents into clinical use involves understanding the nuances of clinical decision-making. This review will provide an in-depth focus on omadacycline in clinical practice.

AREAS COVERED

Literature review of omadacycline utilizing PubMed was performed to provide a comprehensive evaluation of omadacycline pharmacology, microbiology, registrational Phase 3 clinical trials, and post-marketing clinical studies. In addition, the immunomodulatory and other attributes of tetracycline class of antibiotics, of which omadacycline is a member, are reviewed, introducing the concept of antibiotic selection with attention to the bacterial pathogen and human host relationship.

EXPERT OPINION

Omadacycline builds upon the favorable attributes of tetracycline antibiotics and provides very reliable empiric coverage for both Staphylococcus aureus and Streptococcus spp. Clinicians require a more robust understanding of antibiotics, including omadacycline, in order to optimize patient outcomes, streamline care, and reduce medical costs.

Efficacy of Omadacycline Versus Moxifloxacin in the Treatment of Community-Acquired Bacterial Pneumonia by Disease Severity: Results From the OPTIC Study

Background

Severity/mortality risk scores and disease characteristics may assist in deciding whether patients with community-acquired bacterial pneumonia (CABP) require outpatient treatment or hospitalization. The phase 3 OPTIC (Omadacycline for Pneumonia Treatment In the Community) study enrolled patients with Pneumonia Outcomes Research Team (PORT) risk class II–IV. Omadacycline demonstrated noninferiority to moxifloxacin in adults with CABP, at early clinical response (ECR) and posttreatment evaluation (PTE). We assessed efficacy of omadacycline versus moxifloxacin in these patients based on disease severity.

Methods

Patients were randomized 1:1 to receive intravenous (IV) omadacycline (100 mg every 12 hours for 2 doses followed by 100 mg daily [q24h], with optional transition to omadacycline 300 mg orally q24h after 3 days of IV treatment) or moxifloxacin IV 400 mg q24h (with optional transition to 400 mg orally q24h after 3 days of IV treatment). Total treatment duration was 7–14 days. We compared rates of early clinical success (72–120 hours after first dose) and investigator-assessed clinical success at PTE (5–10 days after last dose) in subgroups based (1) on severity/mortality risk scores (PORT, CURB-65, systemic inflammatory response syndrome, quick Sequential [Sepsis-related] Organ Failure Assessment, modified ATS, SMART-COP) and (2) on presence of baseline radiographic characteristics, chronic obstructive pulmonary disease (COPD)/asthma, or bacteremia.

Results

Altogether, 774 patients (omadacycline, n = 386; moxifloxacin, n = 388) were randomized. Clinical success rates (ECR/PTE) were similar between treatment groups (across all subgroups). Efficacy across treatment groups was similar in patients with baseline radiographic characteristics or COPD/asthma, but moxifloxacin had higher clinical success rates in patients with bacteremia.

Conclusions

Efficacy of omadacycline was similar to that of moxifloxacin, regardless of disease severity/mortality risk and disease characteristics.