Safety and tolerability of tedizolid as oral treatment for bone and joint infections

Tedizolid for osteoarticular infections: Evaluation of the published evidence

INTRODUCTION

Tedizolid phosphate, an oxazolidinone antibiotic, has been approved for the treatment of acute bacterial skin and skin structure infections (ABSSSIs). However, its off-label use has been reported in various infections, including osteoarticular infections.

METHODS

A systematic review of data from PubMed, Scopus, and Web of Science was conducted to evaluate the antimicrobial activity, safety, and effectiveness of tedizolid in patients with bone and joint infections, including prosthetic joint infections, osteomyelitis, and septic arthritis. The review encompassed clinical trials, prospective and retrospective studies, and case reports.

RESULTS

A total of 6 in vitro antimicrobial and 15 clinical studies were included in the review. Tedizolid demonstrated high antimicrobial activity across all in vitro studies. In 106 patients from the included clinical studies, tedizolid showed high effectiveness, with therapy success ranging from 76.5 % to 100 % in 4 cohort studies. Additionally, favorable outcomes were reported in 7 of 9 case reports. Tedizolid exhibited a favorable safety profile, with 11 of 15 clinical studies reporting no adverse events in 37 patients. Adverse events leading to therapy discontinuation were observed in 9 out of 124 patients included in the remaining studies.

CONCLUSION

The current appraisal suggests that tedizolid is a promising antibiotic for the treatment of bone and joint infections. Nonetheless, its use should be reserved for multi-drug resistant infections when other approved therapeutic options are limited. Further clinical studies are warranted to substantiate the effectiveness and safety of tedizolid in this patient population.

Suppressive antibiotic treatment (SAT) in the era of MDRO infections: a narrative review

INTRODUCTION

Antibiotics were originally developed to treat acute bacterial infections, and research studies focus their efforts on safety and efficacy in the short term; however, prolonged course of antibiotics has been documented in multiple clinical settings. The aim of this narrative review is to provide a new perspective on SAT and to discuss new therapeuticpossibilities.

AREAS COVERED

We discuss new clinical scenarios in which SAT could be considered. We provided a broad discussion about long-acting agents and new or repurposed oral agents as well as the use of OPAT with elastomeric pumps and an overview of the pipeline of new antifungals. Limitations of SAT are presented in this review and especially patients' adherence issues, possible spread of MDROs, possible rising of the incidence of Clostridioides difficile infections, drug-to-drug interactions and drug-related problems, cost-effectiveness evaluation issues.

EXPERT OPINION

Many research gaps are evident and further studies are needed. Above all, the efficacy and safety of SAT in the different clinical scenarios. Discovery of new molecules against MDROs and ongoing research on PK/PD variables as well as a better understanding of the relationship between SAT and the emergence of resistance could improve SAT usage and reduce the impact of DRPs.

Management of Gram-positive multiresistant bacteria prosthetic joint infection: a narrative review on current and innovative strategies

BACKGROUND

Prosthetic joint infection (PJI) is a devastating complication of arthroplasty surgery, mostly caused by Gram-positive pathogens, including Staphylococcus aureus and coagulase-negative staphylococci. Multidrug resistance is of major concern in this setting: (a) it can negatively impact outcome, restricting the use of the most effective antimicrobials; (b) it may influence the choice of surgical strategies; and (c) it restrains the therapeutic options to newly labelled antimicrobials with limited experience in PJI.

OBJECTIVES

To provide a comprehensive overview of the clinical impact of antimicrobial resistance in Gram-positive PJI and on current and innovative therapeutic strategies.

SOURCES

The review is based on PubMed searches for relevant topics, including multiresistant staphylococci PJI and the discussed specific therapeutic approaches. Given the very few randomized trials in this setting, discussion is mostly based on observational studies and the experience and opinion of the authors.

CONTENT

Methicillin resistance is an important concern in staphylococcal PJI, especially in coagulase-negative staphylococci. However, its impact on the outcome is controversial. Conversely, rifampicin and/or fluoroquinolone resistance are associated with worse prognosis and might be considered when defining difficult-to-treat pathogens in the PJI setting. There is very little experience with recently developed anti-Gram-positive antimicrobial in PJI, but evaluations of their antibiofilm activities are promising, and some of them might represent significant advances regarding antimicrobial tolerance (such as tedizolid) or pharmacokinetic profiles (such as dalbavancin) during long-term treatment required for PJI. Evaluation of innovative strategies in this setting is crucial, including repositioning of current surgical options using local antimicrobial delivery, pharmacokinetic monitoring and modelling to optimize antimicrobial therapy, suppressive antimicrobial treatment and/or phage-based approaches.

IMPLICATIONS

PJIs caused by resistant Gram-positive bacteria-including rifampicin- and/or fluoroquinolone-resistant staphylococci-may be associated with a poorer prognosis. It is therefore essential to optimize medical and surgical management, and to find new therapeutic alternatives.

Comparative In Vitro Drug Susceptibility Study of Five Oxazolidinones Against Mycobacterium tuberculosis in Hainan, China

Oxazolidinones, novel synthetic antibacterials, inhibit protein biosynthesis and show potent activity against Gram-positive bacteria, including Mycobacterium tuberculosis (MTB). In this study, we aimed to compare the in vitro activity of linezolid (LZD) and four oxazolidinones, including tedizolid (TZD), contezolid (CZD), sutezolid (SZD), and delpazolid (DZD), against multidrug-resistant tuberculosis (MDR-TB) and pre-extensively drug-resistant tuberculosis (pre-XDR-TB) isolates from Hainan. We established their epidemiological cut-off values (ECOFFs) using ECOFFinder software and analyzed mutations in rrl (23S rRNA), rplC, rplD, mce3R, tsnR, Rv0545c, Rv0930, Rv3331, and Rv0890c genes to uncover potential mechanisms of oxazolidinone resistance. This study included 177 MTB isolates, comprising 67 MDR and 110 pre-XDR-TB isolates. Overall, SZD exhibited the strongest antibacterial activity against clinical MTB isolates, followed by TZD and LZD, with CZD and DZD showing equivalent but weaker activity (SZDMIC50 = TZDMIC50 < LZDMIC50 < CZDMIC50 = DZDMIC50; SZDMIC90 < TZDMIC90 = LZDMIC90 < CZDMIC90 = DZDMIC90). Significant differences in MIC distribution were observed for TZD (p < 0.0001), CZD (p < 0.01), SZD (p < 0.0001), and DZD (p < 0.0001) compared to LZD but not between MDR-TB and pre-XDR-TB isolates. We propose the following ECOFFs: SZD, 0.5 µg/mL; LZD, TZD, and CZD, 1.0 µg/mL; DZD, 2.0 µg/mL. No statistically significant differences in resistance rates were observed among these five drugs (p > 0.05). We found that eight MTB isolates (4.52% [8/177]) resisted these five oxazolidinones. Among these, only one isolate, M26, showed an amino acid substitution (Arg79His) in the protein encoded by the rplD gene, which conferred cross-resistance to TZD and CZD. Three distinct mutations were identified in the mce3R gene; notably, isolate P604 displayed two insertions that contributed to resistance against all five oxazolidinones. However, no significant correlation was observed between mutations in the rrl, rplC, rplD, mce3R, tsnR, Rv0545c, Rv0930, Rv3331, and Rv0890c genes with oxazolidinone resistance in the clinical MTB isolates tested. In summary, this study provides the first report on the resistance of MTB in Hainan to the five oxazolidinones (LZD, TZD, CZD, SZD, and DZD). In vitro susceptibility testing indicated that SZD exhibited the strongest antibacterial activity, followed by TZD and LZD, while CZD and DZD demonstrated comparable but weaker effectiveness. Mutations in rplD and mce3R were discovered, but further research is needed to clarify their role in conferring oxazolidinone resistance in MTB.

Linezolid and tedizolid adverse effects: a review on serotonin syndrome, myelosuppression, neuropathies, and lactic acidosis

Oxazolidinone antibiotics-linezolid and tedizolid-are often used to treat multidrug-resistant infections. They are highly bioavailable and ideal for transition to enteral therapy when appropriate. However, multiple associated adverse effects are potentially treatment-limiting. The objective of this review is to discuss relevant adverse effects of linezolid and tedizolid, including serotonin syndrome, myelosuppression, neuropathies, and lactic acidosis, and their commonality in real-world experience in the last decade. Mitigation strategies, including the role of therapeutic drug monitoring, are also discussed.

Optic and peripheral neuropathy associated with short and prolonged administration of tedizolid: a review

INTRODUCTION

Tedizolid is a novel antibiotic of the class of oxazolidinones. This review evaluates the published literature on the optic and peripheral neuropathy associated with short and prolonged administration of tedizolid.

AREAS COVERED

A review of published data from 4 databases was conducted, regarding the development of optic and peripheral neuropathy in patients who received tedizolid for short or prolonged duration. A total of 1,212 records were screened; 33 were included in this review. No peripheral or optic neuropathy cases were reported in 6 randomized controlled trials that studied tedizolid use for a short course. In contrast, 2 cases with optic neuropathy (1 not supported by objective findings) in 87 patients of the prospective studies were identified. Additionally, in a total of 277 patients who participated in the 6 retrospective studies, 9 adverse events related to optic or peripheral neuropathy and 1 case with foot drop in 22 patients of the relevant cases reports were recorded.

EXPERT OPINION

The available data suggests that the safety profile of tedizolid is favorable, especially when given for a short time. However, more clinical studies are needed regarding its long-term use, given that the neurotoxicity induced by oxazolidinones may be time and dose-dependent.

Pharmacokinetic/pharmacodynamic analysis of tedizolid phosphate against Staphylococcus aureus and Streptococcus pneumoniae in children, adolescents, and adults by Monte Carlo simulation

OBJECTIVE

The objective of this study was to investigate the cumulative fraction of response of various dosage regimens of tedizolid phosphate against Staphylococcus aureus and Streptococcus pneumoniae in children, adolescents, and adults.

METHODS

Monte Carlo simulations were performed using previously published pharmacokinetic parameters and pharmacodynamic data to evaluate the efficacy of the simulated dosage strategies in terms of area under the concentration-time curve/minimum inhibitory concentration targets of tedizolid.

RESULTS

According to the results of the Monte Carlo simulations, currently approved dosage regimens of tedizolid phosphate were effective in the treatment of acute bacterial skin and skin structure infections (ABSSSIs) caused by methicillin-susceptible S. aureus and methicillin-resistant S. aureus (MRSA) including vancomycin-intermediate, heterogeneous vancomycin-intermediate, and daptomycin-non-susceptible MRSA in adult and paediatric patients aged 12 y and older. High-dose regimens of tedizolid phosphate should be the preferred option to optimize efficacy against ABSSSIs caused by linezolid-resistant MRSA, particularly chloramphenicol-florfenicol resistance-mediated isolates. The dosage regimens of 3 and 4 mg/kg/d of tedizolid phosphate were appropriate to treat ABSSSIs caused by methicillin-susceptible S. aureus and MRSA in children aged 2-6 and 6-12 y, respectively. Approved dosage regimens of tedizolid phosphate for patients older than 12 y may be sufficient against S. pneumoniae pneumonia but insufficient for S. aureus pneumonia. For neutropenic patients, almost all the simulated regimens of tedizolid phosphate were ineffective against S. aureus and S. pneumoniae.

CONCLUSIONS

These pharmacokinetics/pharmacodynamics-based simulations rationalize and optimize the dosage regimens of tedizolid phosphate against S. aureus and S. pneumoniae in children, adolescents, and adults.

Oxazolidinone antibiotics impair ex vivo megakaryocyte differentiation from hematopoietic progenitor cells and their maturation into platelets

Oxazolidinones (linezolid and tedizolid) adverse reactions include thrombocytopenia, the mechanism of which is still largely unknown. In cultured cells, oxazolidinones impair mitochondrial protein synthesis and oxidative metabolism. As mitochondrial activity is essential for megakaryocyte differentiation and maturation into platelets, we examined whether oxazolidinones impair these processes ex vivo and alter, in parallel, the activity of mitochondrial cytochrome c-oxidase (CYTOX; enzyme partly encoded by the mitochondrial genome) and cell morphology. Human CD34+ cells were isolated, incubated with cytokines (up to 14 days) and clinically relevant oxazolidinone concentrations or in control conditions, and used for (i) clonogenic assays [counting of megakaryocyte (CFU-Mk), granulocyte-monocyte (CFU-GM), burst-forming unit-erythroid (BFU-E) colonies]; (ii) the measure of the expression of megakaryocyte surface antigens (CD34 to CD41 and CD42); (iii) counting of proplatelets; (iv) the measurement of CYTOX activity; and (v) cell morphology (optic and electron microscopy). Oxazolidinones caused a significant decrease in BFU-E but not CFU-Mk or CFU-GM colonies. Yet, the megakaryocytic lineage was markedly affected, with a decreased differentiation of CD34+ into CD41+/CD42+ cells, an abolition of proplatelet formation and striking decrease in the numbers of large polylobulated nucleus megakaryocytes, with a complete loss of intracellular demarcation membrane system, disappearance of mitochondria, and suppression of CYTOX activity. These alterations were more marked in cells incubated with tedizolid than linezolid. These data suggest that oxazolidinones may induce thrombocytopenia by impairing megakaryocytic differentiation through mitochondrial dysfunction. Pharmacological interventions to prevent this toxicity might therefore be difficult as mitochondrial toxicity is most probably inherently linked to their antibacterial activity.

Severe Optic Neuropathy Induced by Very Prolonged Tedizolid as Suppressive Therapy: Description of a Case Report and Implication for Better Assessment

The long-term tolerability of linezolid is low because of mitochondrial toxicity, whereas tedizolid may represent a better option for suppressive therapy. We report a first presumed case of tedizolid-associated optic neuropathy after a very prolonged (18-month) intake and believe that screening for optic neuropathy should be considered for patients undergoing tedizolid suppression.

Population pharmacokinetic rationale for intravenous contezolid acefosamil followed by oral contezolid dosage regimens

Contezolid is a novel oxazolidinone antibiotic with a promising safety profile. Oral contezolid and its intravenous (IV) prodrug contezolid acefosamil (CZA) are in development for treatment of diabetic foot and acute bacterial skin and skin structure infections (ABSSSI). The prodrug CZA is converted to active contezolid via intermediate MRX-1352. This study aimed to provide the pharmacokinetic rationale for safe, effective, and flexible dosage regimens with initial IV CZA followed by oral contezolid. We simultaneously modeled plasma concentrations from 110 healthy volunteers and 74 phase 2 patients with ABSSSI via population pharmacokinetics (using the importance sampling estimation algorithm), and optimized dosage regimens by Monte Carlo simulations. This included data on MRX-1352, contezolid, and its metabolite MRX-1320 from 66 healthy volunteers receiving intravenous CZA (150-2400 mg) for up to 28 days, and 74 patients receiving oral contezolid [800 mg every 12 h (q12h)] for 10 days. The apparent total clearance for 800 mg oral contezolid with food was 16.0 L/h (23.4% coefficient of variation) in healthy volunteers and 17.7 L/h (53.8%) in patients. CZA was rapidly converted to MRX-1352, which subsequently transformed to contezolid. The proposed dosage regimen used an IV CZA 2000 mg loading dose with 1000 mg IV CZA q12h as maintenance dose(s), followed by 800 mg oral contezolid q12h (with food). During each 24-h period, Monte Carlo simulations predicted this regimen to achieve consistent areas under the curve of 91.9 mg·h/L (range: 76.3-106 mg·h/L) under all scenarios. Thus, this regimen was predicted to reliably achieve efficacious contezolid exposures independent of timing of switch from IV CZA to oral contezolid.IMPORTANCEThis study provides the population pharmacokinetic rationale for the dosage regimen of the intravenous (IV) prodrug contezolid acefosamil (CZA) followed by oral contezolid. We developed the first integrated population model for the pharmacokinetics of the MRX-1352 intermediate prodrug, active contezolid, and its main metabolite MRX-1320 based on data from three clinical studies in healthy volunteers and phase 2 patients. The proposed regimen was predicted to reliably achieve efficacious contezolid exposures independent of timing of switch from IV CZA to oral contezolid.