Multiple-Dose Oritavancin Evaluation in a Retrospective Cohort of Patients with Complicated Infections

Head-to-head comparison of multi-dose oritavancin and dalbavancin for complicated infections: A propensity score-matched analysis

BACKGROUND

Oritavancin and dalbavancin are long-acting lipoglycopeptide antibiotics approved for the treatment of skin and skin structure infections. Recently, they have been used for outpatient antimicrobial therapy for complicated infections. No head-to-head studies exist for this purpose.

OBJECTIVE

To compare outcomes of patients treated with multiple doses of oritavancin or dalbavancin for complicated infections.

PATIENTS AND METHODS

This was a single-centre, retrospective cohort study evaluating adult patients who received two or more doses of lipoglycopeptides for complicated infections from February 2019 through December 2022. Patients receiving oritavancin were compared to dalbavancin after propensity score-matching. The primary endpoint was clinical success at 90 days. Other endpoints included: 30-day re-admission, 30-day mortality, adverse drug reactions (ADRs), and changes in white blood cell count and inflammatory markers after the first dose.

RESULTS

After exclusions and propensity score-matching, 131 matched pairs (N = 262) were included in the analysis. Most patients were receiving lipoglycopeptide therapy for osteomyelitis. There was no significant difference in clinical success at 90 days in patients who received oritavancin compared to those who received dalbavancin (99 [76%] vs. 103 [79%], respectively; P = 0.556). There was no significant difference in secondary endpoints, however, there was a trend towards higher incidence of ADRs oritavancin compared to dalbavancin (9 [7%] vs. 2 [2%], respectively; P = 0.060) which led to more treatment discontinuation.

CONCLUSION

There was no significant difference in efficacy between multi-dose oritavancin and dalbavancin for the treatment of complicated infections. Both agents were generally well tolerated; however, dalbavancin may be better tolerated when long-term treatment is warranted.

Oritavancin Versus Daptomycin for Osteomyelitis Treatment After Surgical Debridement

INTRODUCTION

Weekly intravenous (IV) oritavancin and daily daptomycin were compared in an outpatient setting following extensive surgical debridement for treating patients with osteomyelitis.

METHODS

This was a retrospective, observational study of patients diagnosed with acute osteomyelitis. Exclusion criteria were the use of Gram-negative antibiotic therapy, use of antibiotics for more than 48 h prior to oritavancin or daptomycin or prior use of > 2 doses of oritavancin or more than 4 weeks of daptomycin. Clinical success was resolution or improvement of symptoms and no further treatment. Data were analyzed with Chi-square test or Fisher's exact test.

RESULTS

Consecutive outpatients (n = 150) with acute osteomyelitis who were treated with oritavancin or daptomycin (1:1) following extensive surgical debridement were identified. Staphylococcus aureus was the most common pathogen (n = 117). No patient in either group received prior antibiotic therapy (previous 30 days) or was hospitalized within 90 days prior to surgical debridement. Twenty-one (28%) patients prescribed oritavancin had chronic kidney disease, seven of whom were receiving hemodialysis or peritoneal dialysis. Compared to oritavancin, patients prescribed daptomycin had higher rates of all-cause readmission [odds ratio (OR) 2.89; p < 0.001], more infection-related readmission (OR 3.19; p < 0.001), and greater likelihood of receiving antibiotics post-discontinuation of initial therapy (OR 2.13; p < 0.001). Repeat surgical debridement was required for 68.0% with daptomycin vs. 23.1% with oritavancin (p < 0.001).

CONCLUSIONS

Oritavancin demonstrated a significantly higher rate of clinical success compared to daptomycin, with lower all-cause and infection-related readmissions, reduced need for repeat surgical debridement, and fewer additional antibiotic requirements.

Oritavancin as sequential therapy for Gram-positive bloodstream infections

BACKGROUND

Oritavancin, a long-acting lipoglycopeptide approved for use in acute bacterial skin and skin structure infections, has limited data evaluating use in serious infections due to Gram-positive organisms. We aimed to assess the effectiveness and safety of oritavancin for consolidative treatment of Gram-positive bloodstream infections (BSI), including infective endocarditis (IE).

METHODS

We conducted a retrospective cohort study evaluating adult patients admitted to University of Colorado Hospital from March 2016 to January 2022 who received ≥ 1 oritavancin dose for treatment of Gram-positive BSI. Patients were excluded if the index culture was drawn at an outside facility or were > 89 years of age. The primary outcome was a 90-day composite failure (clinical or microbiological failure) in those with 90-day follow-up. Secondary outcomes included individual components of the primary outcome, acute kidney injury (AKI), infusion-related reactions (IRR), and institutional cost avoidance.

RESULTS

Overall, 72 patients were included. Mean ± SD age was 54 ± 16 years, 61% were male, and 10% had IE. Organisms most commonly causing BSI were Staphylococcus aureus (68%, 17% methicillin-resistant), followed by Streptococcus spp. (26%), and Enterococcus spp. (10%). Patients received standard-of-care antibiotics before oritavancin for a median (IQR) of 11 (5-17) days. Composite failure in the clinically evaluable population (n = 64) at 90-days occurred in 14% and was composed of clinical and microbiological failure, which occurred in 14% and 5% of patients, respectively. Three patients (4%) experienced AKI after oritavancin, and two (3%) experienced an IRR. Oritavancin utilization resulted in earlier discharge for 94% of patients corresponding to an institutional cost-avoidance of $3,055,804 (mean $44,938/patient) from 1,102 hospital days saved (mean 16 days/patient).

CONCLUSIONS

The use of oritavancin may be an effective sequential therapy for Gram-positive BSI to facilitate early discharge resulting in institutional cost avoidance.

Therapeutic drug monitoring of glycopeptide antimicrobials: An overview of liquid chromatography-tandem mass spectrometry methods

Therapeutic drug monitoring (TDM) is a critical clinical tool used to optimize the safety and effectiveness of drugs by measuring their concentration in biological fluids. These fluids are primarily plasma or blood. TDM, together with real-time dosage adjustment, contributes highly to the successful management of glycopeptide antimicrobial therapies. Understanding pharmacokinetic/pharmacodynamic (PK/PD) properties is vital for optimizing antimicrobial therapies, as the efficacy of these therapies depends on both the exposure of the patient to the drug (PK) and pharmacodynamic (PD) parameters such as the in vitro estimated minimum drug concentration that inhibits bacterial growth (MIC). Liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) is widely recognized as the gold standard for measuring small molecules, such as antibiotics. This review provides a comprehensive overview of LC-MS/MS methods available for TDM of glycopeptide antibiotics, including vancomycin, teicoplanin, dalbavancin, oritavancin, and telavancin.

Oritavancin vs Standard of Care for Treatment of Nonendovascular Gram-Positive Bloodstream Infections

Background

Data is limited comparing oritavancin (ORT) to the standard-of-care (SOC) for the treatment gram-positive blood stream infections (BSI).

Methods

This was a retrospective study of all patients in the Veteran's Affairs Health Care System treated with at least 1 dose of oritavancin or at least 5 days of vancomycin, daptomycin, ceftaroline, ampicillin, ampicillin-sulbactam, nafcillin, oxacillin, or cefazolin for a documented gram-positive BSI from 1 January 2015 to 30 June 2021. Patients with polymicrobial blood cultures or positive cultures from other sites were included if the organisms were sensitive to the incident antimicrobial; no concomitant antimicrobials could be used once the incident agent was started. Individuals were also excluded if they were diagnosed with endocarditis, had a neutrophil count 96-hours of treatment before the incident antimicrobial was started.The primary composite outcome was clinical failure, defined as all-cause mortality within 30-days from the end of therapy, or blood cultures positive for the incident organisms ≥72 hours after administration of the first dose and ≤30 days after the administration of the final dose of the study antimicrobial, or any drug or line-related readmissions within 30-days of hospital discharge.

Results

Two hundred-forty patients were identified for screening with 96 meeting criteria (27 in ORT and 69 in SOC groups). Baseline characteristics were generally balanced between groups except more patients in the ORT group received >96-hours of treatment before the incident antimicrobial was started (70.3% (19/27) vs 13.04% 9/69); P < .001). The pathogen most prevalent was methicillin susceptible Staphylococcus aureus (MSSA) (ORT 33.3% (9/27) vs SOC 46.4% (32/69)). Clinical failure occurred in 7.4% (2/27) in the ORT group and 17.4% (12/69) in SOC (P = .34). No components of the primary outcome were significantly different between groups, but AKI did occur more commonly in the SOC group (27.5% (19/69) vs 3.7% (1/27); P = .01).

Conclusions

ORT appears to be a safe and effective option when directly compared to the SOC for non-endocarditis BSIs.

The Clinical Efficacy of Multidose Oritavancin: A Systematic Review

Oritavancin (ORI) is a semisynthetic lipoglycopeptide approved as a single 1200 mg dose intravenous infusion for the treatment of acute bacterial skin and skin structure infections (ABSSSIs) caused by Gram-positive organisms in adults. The pharmacokinetic/pharmacodynamic (PK/PD) linear kinetic profile and long terminal half-life (~393 h) of ORI make it therapeutically attractive for the treatment of other Gram-positive infections for which prolonged therapy is needed. Multidose regimens are adopted in real-world clinical practice with promising results, but aggregated efficacy data are still lacking. A comprehensive search on PubMed/Medline, Scopus, Cochrane and Google Scholar databases was performed to include papers published up to the end of January 2023. All articles on ORI multiple doses usage, including case reports, with quantitative data and relevant clinical information were included. Two reviewers independently assessed papers against the inclusion/exclusion criteria and for methodological quality. Differences in opinion were adjudicated by a third party. From 1751 potentially relevant papers identified by this search, a total of 16 studies met the inclusion criteria and were processed further in the final data analysis. We extracted data concerning clinical response, bacteriologic response, mortality and adverse events (AEs). From the 16 included papers, 301 cases of treatment with multidose ORIs were identified. Multidose regimens comprised an initial ORI dose of 1200 mg followed by 1200 mg or 800 mg subsequent doses with a varying total number and frequency of reinfusions. The most often treated infections and isolates were osteomyelitis (148; 54.4%), ABSSSI (35; 12.9%) and cellulitis (14; 5.1%); and MRSA (121), MSSA (66), CoNS (17), E. faecalis (13) and E. faecium (12), respectively. Clinical cure and improvement by multidose ORI regimens were observed in 85% (231/272) and 8% (22/272) patients, respectively. Multidose ORI was safe and well tolerated; the most frequent AEs were infusion-related reactions and hypoglycemia. A multidose ORI regimen may be beneficial in treating other Gram-positive infections besides ABSSSIs, with a good safety profile. Further studies are warranted to ascertain the superiority of one multidose ORI scheme or posology over the other.

Role of Oritavancin in the Treatment of Infective Endocarditis, Catheter- or Device-Related Infections, Bloodstream Infections, and Bone and Prosthetic Joint Infections in Humans: Narrative Review and Possible Developments

Oritavancin is a long-acting lipoglycopeptide with in vitro activity against Gram-positive pathogens, as well as good bactericidal activity and sterilisation ability in biofilm. It has been approved for acute bacterial skin and skin structure infections (ABSSSI), but recent reports have demonstrated possible off-label uses, such as for vancomycin resistant enterococci (VRE), deep-seated infections including those involving prosthetic material and invasive infections. The aim of this work is to review the uses of oritavancin outside of ABSSSI, focusing on its real-life applications on infective endocarditis, catheter- or device-related infections, bloodstream infections, and bone and prosthetic joint infections in humans, as well as possible future applications. We performed a narrative review, collecting the literature published between 1 December 2002 and 1 November 2022 on PubMed and the Cochrane Library using the term 'oritavancin'. Available studies have shown how effective it is in different settings, suggesting an opportunity for step-down strategies or outpatient management of infections requiring a long duration of antibiotic treatment. So far, evidence is still scarce, and limited to a few studies and case reports, mostly focusing on Staphylococcus aureus as the major isolate. Concerns about fluid intake for dilution and interaction with coagulation markers also need to be taken into account. Further studies are required in order to assess the safety and effectiveness of Oritavancin in vascular, prosthetic, or device-related infections, as well as in resistant Gram-positive bacteria or enterococcal infections.

Kimyrsa and Orbactiv - A Tale of Two Formulations

Kimyrsa is a new formulation (NF) of the original formulation of oritavancin ([OF] Orbactiv). Comparatively, the obvious benefit with this product is the shortened infusion time and flexibility with solution compatibility, but otherwise maintains a similar pharmacokinetic and microbiologic profile. At present, the NF lacks significant real-world experience relative to other available lipoglycopeptides and thus its place in therapy remains difficult to predict but would not be expected to be significantly different than its OF.

New Perspectives on Antimicrobial Agents: Long-Acting Lipoglycopeptides

The long-acting lipoglycopeptides (LGPs) dalbavancin and oritavancin are semisynthetic antimicrobials with broad and potent activity against Gram-positive bacterial pathogens. While they are approved by the Food and Drug Administration for acute bacterial skin and soft tissue infections, their pharmacological properties suggest a potential role of these agents for the treatment of deep-seated and severe infections, such as bloodstream and bone and joint infections. The use of these antimicrobials is particularly appealing when prolonged therapy, early discharge, and avoidance of long-term intravascular catheter access are desirable or when multidrug-resistant bacteria are suspected. This review describes the current evidence for the use of oritavancin and dalbavancin in the treatment of invasive infections, as well as the hurdles that are preventing their optimal use. Moreover, this review discusses the current knowledge gaps that need to be filled to understand the potential role of LGPs in highly needed clinical scenarios and the ongoing clinical studies that aim to address these voids in the upcoming years.

Orthopaedic Implant-Associated Staphylococcal Infections: A Critical Reappraisal of Unmet Clinical Needs Associated with the Implementation of the Best Antibiotic Choice

Infections associated with orthopaedic implants represent a major health concern characterized by a remarkable incidence of morbidity and mortality. The wide variety of clinical scenarios encountered in the heterogeneous world of infections associated with orthopaedic implants makes the implementation of an optimal and standardized antimicrobial treatment challenging. Antibiotic bone penetration, anti-biofilm activity, long-term safety, and drug choice/dosage regimens favouring outpatient management (i.e., long-acting or oral agents) play a major role in regards to the chronic evolution of these infections. The aim of this multidisciplinary opinion article is to summarize evidence supporting the use of the different anti-staphylococcal agents in terms of microbiological and pharmacological optimization according to bone penetration, anti-biofilm activity, long-term safety, and feasibility for outpatient regimens, and to provide a useful guide for clinicians in the management of patients affected by staphylococcal infections associated with orthopaedic implants Novel long-acting lipoglycopeptides, and particularly dalbavancin, alone or in combination with rifampicin, could represent the best antibiotic choice according to real-world evidence and pharmacokinetic/pharmacodynamic properties. The implementation of a multidisciplinary taskforce and close cooperation between microbiologists and clinicians is crucial for providing the best care in this scenario.

Activity of Oritavancin Against Gram-positive Pathogens Causing Bloodstream Infections in the United States Over 10 Years: Focus on Drug-Resistant Enterococcal Subsets (2010-2019)

Oritavancin displayed potent and stable activity (MIC₉₀ range of 0.06 to 0.5 mg/L) over a 10-year period (2010 to 2019) against Gram-positive pathogens that cause bloodstream infections (BSI), including methicillin-resistant Staphylococcus aureus (MRSA) and resistant subsets of Enterococcus spp. Daptomycin and linezolid were also active against methicillin-resistant S. aureus and vancomycin-resistant Enterococcus (VRE). Only oritavancin and linezolid remained active against Enterococcus faecium isolates displaying an elevated daptomycin MIC (i.e., 2 to 4 mg/L). Proportions of methicillin-resistant S. aureus and vancomycin-resistant Enterococcus within the respective S. aureus and enterococcal populations decreased over this period.

Long-Acting Lipoglycopeptides Can Interfere With Vancomycin Therapeutic Drug Monitoring

Oritavancin and dalbavancin are long-acting lipoglycopeptides with activity against susceptible gram-positive bacteria, including methicillin-resistant Staphylococcus aureus. Though similar in structure to traditional glycopeptide antibiotics like vancomycin, these antibiotics have terminal half-lives >10 days, and, as a result, there is potential for administration of vancomycin to a patient while oritavancin or dalbavancin are still appreciably present in serum. Given the structural similarities, this creates an opportunity for lab assay interference when performing therapeutic drug monitoring for vancomycin. Following higher-than-expected serum vancomycin concentrations in a patient who received both oritavancin and vancomycin within a short time frame, we evaluated the potential for lipoglycopeptide interference with clinical vancomycin assays. Five platforms covering 3 immunoassay technologies were used to quantify vancomycin concentrations in serum spiked with oritavancin or dalbavancin. Oritavancin generated spurious vancomycin concentrations (20%-84% increase) in both enzyme-multiplied immunoassay technique and a particle-enhanced turbidimetric inhibition immunoassay. However, the improper detection of oritavancin was not consistent across all particle-enhanced turbidimetric inhibition immunoassay platforms. Dalbavancin interference was not detected on any of the platforms tested. The interference from oritavancin may result in falsely elevated vancomycin concentrations and, subsequently, inappropriately adjusted vancomycin doses.

Role or oritavancin and dalbavancin in acute bacterial skin and skin structure infections and other potential indications

PURPOSE OF REVIEW

To discuss the currently available evidence about the use oritavancin and dalbavancin for the treatment of acute bacterial skin and skin structure infections (ABSSSI) and for other potential indications.

RECENT FINDINGS

In this review, we briefly summarize the available data on efficacy (from randomized controlled trials) and on effectiveness and cure rates (from observational studies) pertaining to the use of oritavancin and dalbavancin either for ABSSSI or for other indications.

SUMMARY

Oritavancin and dalbavancin are valid options for outpatient therapy and early discharge in patients with ABSSSI, especially when adherence to oral therapy cannot be guaranteed or no oral choices are available. Furthermore, it is worth noting that a non-negligible portion (sometimes the majority) of oritavancin and dalbavancin use in available real-life experiences is for indications other than ABSSSI, especially for Gram-positive osteomyelitis and endocarditis. The number of studies on the use of long-acting lipoglycopeptides for these currently off-label indications is rapidly increasing and will help to further optimize the use of these peculiar antibiotics in the forthcoming future.

Long-Acting Lipoglycopeptides for the Treatment of Bone and Joint Infections

Background: The long-acting lipoglycopeptides dalbavancin and oritavancin possess excellent microbiologic activity against gram-positive bacteria and provide prolonged tissue exposure at sites of infection. Moreover, these antibiotics are well tolerated and do not require therapeutic drug monitoring. Methods: Pharmacokinetic/pharmacodynamic experiments ascertained that one to two doses of these long-acting agents can provide an extended period (≥6 weeks) of antimicrobial therapy. Results: Clinical studies subsequently found that microbiologic and clinical response rates with these agents were comparable to standard antibiotic agents used in the treatment of bone and joint infections. In addition, pharmacoeconomic analyses have discovered cost savings with the use of these antimicrobial agents in the treatment of serious deep-seated bacterial infections. Conclusions: Thus, these long-acting lipoglycopeptides offer potential for cost-effective outpatient parenteral antibiotic therapy of difficult to treat infections, such as osteomyelitis.

Continued Dosing of Oritavancin for Complicated Gram-Positive Infections

Several retrospective and cohort analyses have suggested that continued dosing of oritavancin is both safe and efficacious for complicated Gram-positive infections, such as methicillin-resistant Staphylococcus aureus and vancomycin-resistant enterococci.

Intracellular Staphylococcus aureus in bone and joint infections: A mechanism of disease recurrence, inflammation, and bone and cartilage destruction

Bone and joint infections are devastating afflictions. Although medical interventions and advents have improved their care, bone and joint infections still portend dismal outcomes. Indeed, bone and joint infections are associated with extremely high mortality and morbidity rates and, generally, occur secondary to the aggressive pathogen Staphylococcus aureus. The consequences of bone and joint infections are further compounded by the fact that although they are aggressively treated, they frequently recur and result in massive bone and articular cartilage loss. Here, we review the literature and chronicle the fact that the fundamental cellular components of the musculoskeletal system can be internally infected with Staphylococcus aureus, which explains the ready recurrence of bone and joint infections even after extensive administration of antibiotic therapy and debridement and offer potential treatment solutions for further study. Moreover, we review the ramifications of intracellular infection and expound that the massive bone and articular cartilage loss is caused by the sustained proinflammatory state induced by infection and offer potential combination therapies for further study to protect bone and cartilage.

Successful treatment of a prosthetic hip infection due to Enterococcus faecalis with sequential dosing of oritavancin and prosthesis preservation without prosthetic joint surgical manipulation

A patient with a prosthetic joint infection (PJI) complicated with deep surgical site infection due to vancomycin-susceptible Enterococcus faecalis. The initial treatment consisted of 10 days with daptomycin plus ampicillin. The hip prosthesis was retained and salvaged with six outpatient sequential doses of oritavancin 1200 mg every seven days without intra-articular irrigation or other surgical interventions. The patient was ambulating independently without symptoms after ten months of the last treatment of oritavancin.

On- and off-label utilization of dalbavancin and oritavancin for Gram-positive infections

BACKGROUND

Long-acting lipoglycopeptides (laLGPs) are FDA approved only for acute bacterial skin and skin structure infections (ABSSSIs). However, these antibiotics show promise for off-label use, reductions in hospital length of stay (LOS) and healthcare cost savings.

OBJECTIVES

To assess the effectiveness, safety, impact on LOS and estimated cost savings from laLGP treatment for Gram-positive infections.

METHODS

Retrospective cohort of adult patients who received at least one dose of laLGPs at the University of Colorado Health system. Descriptive statistics were utilized for analysis.

RESULTS

Of 59 patients screened, 56 were included: mean age 47 years, 59% male and 30% injection drug users/polysubstance abusers (dalbavancin, 71%; oritavancin, 25%; both, 4%). Most common indications for laLGP: ABSSSIs (36%), osteomyelitis (27%) and endocarditis (9%). Most common isolated pathogens: MSSA and MRSA (25% and 19%, respectively), Enterococcus faecalis (11%) and CoNS (11%). Previous antibiotics were administered for a median of 13 days (IQR = 7.0-24.5 days) and laLGPs for a median of one dose (IQR = 1-2 doses). Ten (18%) patients were lost to follow-up. Clinical failure was found in 7/47 (15%) cases with adequate follow-up. Mild adverse effects occurred in six (11%) patients. Projected reduction in hospital LOS and health-system costs were 514 days (9.18 days/person average) and $963456.72 ($17204.58/person average), respectively.

CONCLUSIONS

Prospective trials are needed to validate the use of these antibiotics for Gram-positive infections in practice, with the hope that they will reduce hospital LOS and the need for daily antibiotic infusions to provide alternative options for patients not qualifying for outpatient parenteral antimicrobial therapy.

Treatment of osteoarticular, cardiovascular, intravascular-catheter-related and other complicated infections with dalbavancin and oritavancin: A systematic review

BACKGROUND

There is increasing interest in the use of oritavancin and dalbavancin for complicated Gram-positive infections as an alternative to in-hospital intravenous or outpatient antimicrobial therapy.

OBJECTIVE

To evaluate the efficacy and safety of long-acting lipoglycopeptides (laLGPs) in patients with osteoarticular, cardiovascular, intravascular-catheter-related and other complicated infections.

METHODS

A systematic literature search was performed using 'dalbavancin' and 'oritavancin' as search terms. For inclusion in this review, studies had to include at least one human subject treated for an indication other than acute bacterial skin and skin structure infections. The primary outcome for this review was clinical success as defined by each individual study, and patients were stratified by type of infection.

RESULTS

In total, 38 studies (18 randomized controlled trials/case series and 20 case reports) met the inclusion criteria. The most common off-label indication for oritavancin and dalbavancin was osteoarticular infection, with a median success rate of 73% [interquartile range (IQR) 58-85%] among the 14 studies with more than one patient. The success rate for endocarditis and cardiac-device-related infections was 68% (IQR 56-86%) among nine studies, and the success rate for catheter-related bloodstream infection was 75% (IQR 59-90%) among seven studies. Among the 16 studies of almost 700 patients receiving laLGPs, there were 98 reports of adverse events, resulting in 13% of treated patients reporting an event.

CONCLUSIONS

This review provides evidence that laLGPs are safe and efficacious for osteoarticular, cardiovascular, intravascular-catheter-related and other complicated infections. Further research is needed to confirm these results.

A Two-Dose Oritavancin Regimen Using Pharmacokinetic Estimation Analysis

Background

Antibiotics for the treatment of complicated, multidrug-resistant Gram-positive infections are limited, especially when prolonged treatment is necessary. Oritavancin is approved for the treatment of serious skin infections as a 1200 mg single-dose regimen, but case reports describe supplemental doses given at weekly intervals ranging from 800 mg to 1200 mg.  

Objective

This study determined population pharmacokinetic estimates for a 1200 mg single dose with and without an 800 mg dose 1 week apart.

Methods

A simulated oritavancin 1200 mg dose was infused over 3 h followed 7 days later by a simulated 800 mg dose infused over 3 h for pharmacokinetic estimation.

Results

The oritavancin dosing displayed predictable linear pharmacokinetics and therapeutic concentrations. The total and free oritavancin concentrations remained above the susceptibility breakpoint (0.12 mg/L) for 8 weeks and 4.6 weeks, respectively, with the two-dose regimen. This was significantly greater than the single-dose regimen. This regimen also results in a greater area under the drug concentration–time curve (AUC) above the susceptibility breakpoint compared to the single-dose regimen (p < 0.001), and it maintains a high AUC:minimum inhibitory concentration (MIC) ratio against organisms with MICs up to 0.25 mg/L.

Conclusion

These results along with the observational clinical reports of success and safety with this dosing scheme of 1200 mg followed by 800 mg 7 days later provide evidence for further evaluation of this approach when prolonged oritavancin treatment may be indicated.

Treatment of Acute Osteomyelitis with Once-Weekly Oritavancin: A Two-Year, Multicenter, Retrospective Study

Background

Acute osteomyelitis is typically caused by Gram-positive pathogens, commonly antibiotic-resistant Staphylococcus species. Standard antibiotic treatment is challenging due to required multiple daily doses, therapeutic drug monitoring, and parenteral administration for at least 4 weeks. Oritavancin is a long-acting lipoglycopeptide antibiotic approved as a single 1200 mg dose for the treatment of adult patients with acute bacterial skin and skin structure infections.

Objective

To characterize the real-world use, efficacy, and safety of oritavancin in adult patients with acute osteomyelitis.

Methods

This was a 2-year, multicenter, retrospective, descriptive study of patients treated for acute osteomyelitis with weekly doses of oritavancin. End of therapy evaluation (ETE) was defined as evaluation at 7–10 days after the last dose of oritavancin, and post-therapy assessment (PTE) was at 3 months and 6 months. At ETE and PTE, patients were interviewed via telephone for clinical outcomes, using a standard questionnaire. Electronic medical record review was also conducted.

Results

134 patients were treated with oritavancin for acute osteomyelitis across 20 different Metro Infectious Disease Consultants infusion centers in six states. Of total positive cultures, 71.9% (92/128) were methicillin-resistant Staphylococcus aureus (MRSA) from deep wounds, bone, or joint culture; an additional nine (6.7%) of 134 patients presented with concomitant MRSA bacteremia. Oritavancin was administered via intravenous catheter; patients received an initial treatment of 1200 mg and then 800 mg weekly thereafter for a total number of doses of four (n = 118) or five (n = 16). 118 patients (88.1%) of the baseline 134 patients achieved clinical success at the ETE timepoint. 130 patients were available for PTE at 3 months and 6 months. Overall, relapse or persistent infection was diagnosed in 13/134 (9.7%) patients. Nine (6.7%) of 134 patients were admitted to the hospital during the follow-up period but none for osteomyelitis. Adverse events were reported in five (3.7%) patients including hypoglycemia-related symptoms (three patients), tachycardia (one patient), and tachycardia with chest pain (one patient). None of these patients were hospitalized due to adverse events, and all patients eventually finished their treatment regimens.

Conclusion

This is the largest real-world clinical study of adult patients treated with oritavancin for acute osteomyelitis. Use of oritavancin for acute osteomyelitis infection resulted in a high rate of positive clinical outcomes and a low incidence of adverse events, thereby providing potential for a convenient, effective, and safe therapeutic option. Future prospective and comparative studies are needed to validate these findings.

Real-World Use of Oritavancin for the Treatment of Osteomyelitis

Osteomyelitis is a difficult-to-treat disease that can require both surgical debridement and a prolonged course of antimicrobial therapy. Current standard of care for the antimicrobial treatment of osteomyelitis is fraught with multiple challenges and limitations. Patients typically require the insertion of an indwelling catheter for single or multiple daily intravenous antibiotic infusions for up to 6 weeks. Currently, there are treatment guidelines for only vertebral osteomyelitis, indicating the complexity of the condition. Oritavancin is a long-acting, second-generation lipoglycopeptide, administered intravenously once per week, which has potential to be a useful alternative in the treatment of osteomyelitis. This article reviews occurrence and outcomes of off-label oritavancin use for treatment of osteomyelitis as described in case reports. Analysis included 23 patients treated for osteomyelitis with single- or multiple-dose oritavancin. Overall, clinical cure or improvement was achieved in 87% of patients, and adverse events were mild and reported in only two patients. Clinical efficacy was demonstrated in 81.8% of methicillin-resistant Staphylococcus aureus (MRSA), 71.4% of methicillin-sensitive S. aureus (MSSA), 50% of vancomycin-resistant Enterococcus (VRE), and in the single case of Streptococcus pyogenes. Oritavancin has shown efficacy against Gram-positive pathogens in osteomyelitis, and offers a possible outpatient treatment option for osteomyelitis patients. Future studies are needed to determine dosing frequency in osteomyelitis patients.

Real-World Evidence Studies of Oritavancin Use in Gram-Positive Infections Augment Randomized Controlled Trials to Address Clinical and Economic Outcomes

Randomized controlled trials (RCTs) sponsored by pharmaceutical manufacturers for regulatory approval are conducted with restrictive criteria in an effort to definitively demonstrate the safety and efficacy of a drug or biologic. Unfortunately, the strict enrollment criteria in RCTs may exclude patients likely to receive the medication in a real-world clinical practice. Antibiotic RCTs for registration are designed to show noninferiority against standard of care or best available therapy, often minimizing clinical differentiation needed by clinicians to select the optimal agent for their patients. Lastly, RCTs do not include pharmacoeconomic data that would add a cost basis for determining the value of one product over another. Real-world studies may add support to the safety and efficacy demonstrated from RCTs and address patient populations excluded from clinical development programs. This supplement presents several real-world studies demonstrating the clinical and economic outcomes of various uses of oritavancin to augment the evidence published from RCTs. Clinicians may decide how to use this information in their own practice settings.

Dalbavancin for the Treatment of Complicated Gram-Positive Skin and Soft Tissue Infections

New antimicrobial agents have been developed to treat infections caused by methicillin-resistant Staphylococcus aureus and other multidrug-resistant pathogens. Dalbavancin is a novel semisynthetic lipoglycopeptide antibiotic, particularly active against methicillin-resistant Staphylococcus aureus. Due to its unique pharmacological characteristics and longer half-life, it can be administered once-weekly or every 15 days and in outpatient setting. Currently, it is indicated for complicated skin and soft tissue infections, but accumulating evidence points to its off-label efficacy in osteomyelitis and endocarditis. Further experience is still needed to increase our knowledge on the role of dalbavancin in a wider range of Gram-positive infections requiring prolonged antimicrobial treatment.

Clinical Outcomes and Economic Impact of Oritavancin for Gram-Positive Infections: A Single Academic Medical Center Health System Experience

BACKGROUND

Vancomycin treatment of complicated Gram-positive infections is associated with laboratory monitoring, nephrotoxicity, and multiple daily dosing. Oritavancin, a lipoglycopeptide antibiotic with a once-weekly dosing strategy and similar but slightly broader spectrum of activity, presents several opportunities over vancomycin to improve compliance and convenience for the patient. Minimal real-world clinical and acquisition cost data in the inpatient setting and clinical data surrounding multiple dosing in the outpatient setting have limited oritavancin use despite its potential logistic advantages.

OBJECTIVES

We describe inpatient and outpatient oritavancin administration, clinical outcomes, and economic impact.

METHODS

This was a single-center, retrospective case series of patients treated with at least one dose of oritavancin between May 2015 and September 2017 at an academic medical center in the USA. A simplified cost-avoidance analysis was conducted assuming the patient had a national health insurance plan and focused on hospital days prevented.

RESULTS

Seventy-five patients received oritavancin during the study period. The most common use of oritavancin was in patients with acute bacterial skin and skin structure infections (ABSSSI), defined as cellulitis, abscess or non-surgical wounds (n = 25, 33%), followed by surgical wound infections (n = 12, 16%) and osteomyelitis or septic arthritis (n = 10, 13%). Clinical cure or improvement was achieved in 68 patients (93.2%), while five patients (6.8%) failed treatment; adverse reactions were reported in nine patients (12%). Thirty-five patients received oritavancin as inpatients; 20 patients (57%) had at least one hospital day avoided due to inpatient oritavancin administration resulting in a total cost avoidance of US$343,654.

CONCLUSION

In this series of 75 patients with Gram-positive infections, oritavancin treatment resulted in clinical cure or improvement in most patients, and was generally well tolerated. Inpatient administration may avoid costs and outpatient administration is a reasonable consideration for patients in which prolonged antibiotic therapy is necessary.

Advantages of Outpatient Treatment with Long-Acting Lipoglycopeptides for Serious Gram-Positive Infections: A Review

Treatment of serious gram-positive infections presents multiple challenges. Treatment often results in prolonged hospitalization for administration of intravenous antimicrobials and presents an inefficient use of hospital resources. Prolonged hospitalization is typically also unfavorable to patient preferences and potentially subjects patients to additional health care-associated complications. Current strategies of transition to outpatient settings-outpatient parenteral antimicrobial therapy and use of oral antibiotics-often do not adequately serve vulnerable populations for whom there is often no alternative to inpatient therapy. Specifically, people who use drugs, those who cannot reliably adhere to unsupervised treatment (poor mental or physical health), people with complicating life circumstances (e.g., homelessness, incarceration, rural location), and those with inadequate health insurance remain hospitalized for weeks longer than persons without such conditions. We suspected that long-acting lipoglycopeptides (laLGP), such as dalbavancin and oritavancin, may be useful in patient transitions to outpatient settings. Thus, we conducted a search of the peer-reviewed literature using the PubMed, Google Scholar, and MEDLINE databases. Based on accumulating literature, it appears that laLGPs offer a reliable alternative therapeutic strategy that addresses many of the personal and systemic barriers to the traditional transitioning approaches. Current evidence also suggests that these agents may be cost-effective from patient, payer, and hospital perspectives. Barriers to broader use of laLGPs include, among others, a relative lack of prospective data regarding efficacy in serious infections, a narrow United States Food and Drug Administration-approved indication restricted to only acute bacterial skin and skin structure infections, and lack of reimbursement infrastructure for inpatient settings.

The CHROME Study, a Real-world Experience of Single- and Multiple-Dose Oritavancin for Treatment of Gram-Positive Infections

Background

Oritavancin (ORI) is a long-acting lipoglycopeptide indicated for the treatment of adult patients with acute bacterial skin and skin structure infections (ABSSSIs) caused or suspected to be caused by susceptible Gram-positive (GP) pathogens.

Methods

Data collected from a retrospective observational program (2014–2017), Clinical and Historic Registry and Orbactiv Medical Evaluation (CHROME), describe the utilization, outcomes, and adverse events (AEs) associated with ORI in 440 patients treated at 26 US sites for ABSSSI and other GP infections.

Results

Clinical success in evaluable patients receiving at least 1 dose of oritavancin was 88.1% (386/438). In a subgroup of patients who received ORI for skin and soft tissue infections (n = 401) and bacteremia (n = 7), clinical success was achieved in 89.0% and 100%, respectively. A cohort of 32 patients received 2–10 ORI doses separated by no more than 14 days for complicated GP infections. Clinical success was observed in 30 of 32 patients (93.8%), including 10 of 11 (90.9%) patients with bone and joint infections and 7 of 8 (87.5%) patients with osteomyelitis. In the safety evaluable population, the overall rate of AEs was 6.6%.

Conclusions

We describe results from a real-world program that includes the largest multicenter, retrospective, observational study in patients who received at least 1 dose of ORI for the treatment of GP infections. This study confirms that ORI is an effective, well-tolerated antibiotic used in single and multiple doses for the treatment of ABSSSIs and complicated GP infections.

Treatment of Multidrug-Resistant Vancomycin-Resistant Enterococcus faecium Hardware-Associated Vertebral Osteomyelitis with Oritavancin plus Ampicillin

Weekly oritavancin plus ampicillin continuous infusion combination therapy was used to successfully treat a deep spine vancomycin-resistant Enterococcus faecium infection associated with hardware. Checkerboard and time-kill assays confirmed synergy between these two antibiotics. Further synergies of oritavancin and ampicillin with rifampin or the endogenous human antimicrobial peptide cathelicidin LL-37 were demonstrated.

Prevention and Treatment of Multidrug-Resistant Organisms in End-Stage Renal Disease

Chronic kidney disease patients are at high risk for infections because of multidrug-resistant organisms. Infections are the second most common cause of death in patients with ESRD. Patients with ESRD are prone to infections given alterations in immunity, increased rates of colonization with multidrug-resistant organisms, increased hospitalizations, and interactions with health care systems. Infections range from urinary tract infections, pneumonia, skin and soft tissue infections, central line-associated bloodstream infections to sepsis. A coordinated collaborative effort using a multipronged approach must be stressed to reduce the burden of infections. Preventive measures such as hand hygiene, antibiotic stewardship, immunizations, and minimizing central venous catheters are critical to curtail infections with multidrug-resistant organisms. Empirical and targeted treatment for multidrug-resistant organisms may require collaboration with infectious disease providers to improve outcomes in these serious infections. It is imperative to address multidrug-resistant organisms in ESRD patients at this juncture to improve medical outcomes now and for the future.

Treatment of chronic osteomyelitis with multidose oritavancin: A case series and literature review

Osteomyelitis remains difficult to treat, typically requiring a prolonged course of intravenous (i.v.) antibiotics. The optimal route and duration of antibiotics remains ill-defined due to limited prospective clinical trials. Oritavancin is a long-acting, semisynthetic lipoglycopeptide antibiotic with rapid concentration-dependent bactericidal activity against many Gram-positive organisms. Favourable pharmacokinetics makes oritavancin an appealing alternative to currently available antibiotics requiring daily infusion to decrease the risk of vascular access complications associated with outpatient antimicrobial therapy. The purpose of this study was to report the outcomes of nine patients with chronic osteomyelitis receiving multidose oritavancin. Using electronic medical records, patients aged ≥18 years treated with i.v. oritavancin between September 2015 and April 2018 at Downtown Dublin Wound Center, a hospital-owned outpatient wound care clinic and infusion centre affiliated with Meadows Regional Health System in Dublin, GA, were identified. Of 12 cases reviewed, 9 patients received at least two doses of i.v. oritavancin for the treatment of chronic osteomyelitis. All nine patients experienced clinical cure at 6-month follow-up after the last dose of oritavancin. Multidose oritavancin was found to be a safe and efficacious option for chronic osteomyelitis when treatment options are limited by patient complexities or barriers in their ability to access healthcare services.