Management and Outcomes of Patients at a Specialty Clinic for Clostridioides difficile Infection

Vancomycin and fidaxomicin taper regimens were the most common treatment strategies employed but nearly half of patients (40/83) referred to our Clostridioides difficile infection (CDI) clinic did not require further treatment. The overall 60-day CDI recurrence rate was 16.9% (11/65). CDI management at a dedicated clinic may improve clinical outcomes.

difficile toxin B2: insights from computational simulations and mutational analyses for antibody design

Clostridioides difficile infection (CDI) is a significant concern caused by widespread antibiotic use, resulting in diarrhea and inflammation from the gram-positive anaerobic bacterium C. difficile. Although bezlotoxumab (Bez), a monoclonal antibody (mAb), was developed to address CDI recurrences, the recurrence rate remains high, partly due to reduced neutralization efficiency against toxin B2. In this study, we aimed to enhance the binding of Bez to C. difficile toxin B2 by combining computational simulations and mutational analyses. We identified specific mutations in Bez, including S28R, S31W/K, Y32R, S56W and G103D/S in the heavy chain (Hc), and S32F/H/R/W/Y in the light chain (Lc), which significantly improved binding to toxin B2 and formed critical protein-protein interactions. Through molecular dynamics simulations, several single mutations, such as HcS28R, LcS32H, LcS32R, LcS32W and LcS32Y, exhibited superior binding affinities to toxin B2 compared to Bez wild-type (WT), primarily attributed to Coulombic interactions. Combining the HcS28R mutation with four different mutations at residue LcS32 led to even greater binding affinities in double mutants (MTs), particularly HcS28R/LcS32H, HcS28R/LcS32R and HcS28R/LcS32Y, reinforcing protein-protein binding. Analysis of per-residue decomposition free energy highlighted key residues contributing significantly to enhanced binding interactions, emphasizing the role of electrostatic interactions. These findings offer insights into rational Bez MT design for improved toxin B2 binding, providing a foundation for developing more effective antibodies to neutralize toxin B2 and combat-related infections.Communicated by Ramaswamy H. Sarma.

Elucidation of bezlotoxumab binding specificity to toxin B in Clostridioides difficile

C. difficile or Clostridioides difficile infection (CDI) is currently one of the major causes of epidemics worldwide. Toxin B from Clostridioides difficile toxin B (TcdB) infection is the main target protein inhibiting CDI recurrence. Clinical research suggested that bezlotoxumab's (Bez) efficiency is significantly reduced in neutralizing the B2 strain compared to the B1 strain. The monoclonal antibody (mAb) functions by binding to the epitope 1 and 2 regions in the combined repetitive oligopeptide (CROP) domain. Some binding residues are distinctively different between B1 and B2 strains. In this work, we aimed to elucidate and compare insights into the interaction of toxins B1 and B2 in complex with Bez by using all-atom molecular dynamics (MD) simulations and binding free energy calculations. The predicted ΔGbinding values suggested that the antibody (Ab) could bind to toxin B1 significantly better than B2, supported by higher salt bridge and hydrogen bonding (H-bonding) interactions, as well as the number of contact residues between the two focused proteins. The toxin B1 residues important for binding with Bez were E1878, T1901, E1902, F1905, N1941, V1946, N2031, T2032, E2033, V2076, V2077, and E2092. The lower susceptibility of Bez towards toxin B2 was primarily due to a change of residue E2033 from glutamate to alanine (A2033) and the loss of E1878 and E1902 contributions, as determined by the intermolecular interaction changes from the dynamic residue interaction network (dRIN) analysis. The obtained data strengthen our understanding of Bez/toxin B binding.

Efficacy of Bezlotoxumab Against Clostridioides difficile Infection: A Case-Series Study at a University Hospital in Japan and Literature Review

Background Clostridioides difficile infection (CDI) recurrence is a public health concern as well as a health economic burden. Bezlotoxumab treatment is one way to prevent recurrence; however, its clinical results have not been reported in Japan. Therefore, we investigated the efficacy and safety of bezlotoxumab in patients with CDI at a university hospital in Japan and compared them with previously reported findings. Methodology We retrospectively examined all patients with some risk factors for recurrent CDI who received bezlotoxumab at the discretion of physicians at the Aichi Medical University Hospital, Aichi, Japan, between July 2018 and July 2022. The primary outcome was the three-month CDI recurrence rate. The secondary outcomes were an initial clinical cure and the six-month CDI recurrence rate. The safety of the administration was also assessed. Results A total of nine patients who received bezlotoxumab were included during the study period. The rate of CDI recurrence within three months was 28.5% (2/9). Two patients died due to other causes before their diarrhea improved. None of the patients experienced CDI recurrence between three and six months after the initial clinical cure of the baseline episode. Patients showed good tolerability to bezlotoxumab with no adverse effects. Two patients with a single episode of CDI recurrence before bezlotoxumab administration showed no recurrence. Conclusions In this Japanese case-series study, the efficacy of bezlotoxumab in preventing CDI recurrence in elderly patients with CDI and multiple underlying diseases was inferior to that reported in previous studies that analyzed real-world data. It is possible that bezlotoxumab may not be fully effective in elderly patients with CDI.

Double-Blind, Placebo-Controlled Study of Bezlotoxumab in Children Receiving Antibacterial Treatment for Clostridioides difficile Infection (MODIFY III)

BACKGROUND

Therapies to prevent recurrence of Clostridioides difficile infection (CDI) in pediatric patients are needed. Bezlotoxumab is a fully human monoclonal antibody approved for prevention of recurrent CDI in adults. We assessed the pharmacokinetics, safety, tolerability, and efficacy of bezlotoxumab in pediatric patients.

METHODS

MODIFY III was a multicenter, double-blind, placebo-controlled study of bezlotoxumab in children (1 to <18 years) receiving antibacterial treatment for CDI. Participants were randomized 3:1 to receive a single infusion of bezlotoxumab (10 mg/kg) or placebo and were stratified by age at randomization (cohort 1: 12 to <18 years, cohort 2: 1 to <12 years). The primary objective was to characterize bezlotoxumab pharmacokinetics to support dose selection for pediatric patients; the primary endpoint was the area under the bezlotoxumab serum concentration-time curve (AUC0-inf). Safety, tolerability, and efficacy were monitored for 12 weeks post-infusion.

RESULTS

A total of 148 participants were randomized and 143 were treated: 107 with bezlotoxumab and 36 with placebo (cohort 1 n = 60, cohort 2 n = 83; median age 9.0 years); 52.4% of participants were male and 80.4% were white. Geometric mean ratios (90% CI) for bezlotoxumab AUC0-inf were 1.06 (0.95, 1.18) and 0.82 (0.75, 0.89) h * μg/mL for cohorts 1 and 2, respectively. Bezlotoxumab 10 mg/kg was generally well-tolerated with an adverse event profile similar to placebo, including no treatment discontinuations due to adverse events. CDI recurrence was low and comparable for bezlotoxumab (11.2%) and placebo (14.7%).

CONCLUSIONS

The results of this study support the bezlotoxumab dose of 10 mg/kg for pediatric patients.

TRIAL REGISTRATION

NCT03182907 at ClinicalTrials.gov.

How Should We Determine the Role of Bezlotoxumab for Pediatric Clostridioides difficile Infection?

The newly published MODIFY III trial established a safe pediatric dose of bezlotoxumab but did not conclusively demonstrate efficacy in decreasing the rate of recurrence of Clostridioides difficile infection in children. This editorial addresses considerations for bezlotoxumab use in pediatrics.

Clostridioides difficile Infection in an Italian Tertiary Care University Hospital: A Retrospective Analysis

Clostridioides difficile infection (CDI) is a significant cause of morbidity and mortality, mostly in frail patients. Notification is not mandatory in Italy, and data on incidence, risk of death, and recurrence are lacking. The purpose of this study was to determine CDI incidence and risk factors for mortality and recurrence. The "ICD-9 00845" code in hospital-standardized discharged forms (H-SDF) and microbiology datasets were used to retrieve CDI cases at Policlinico Hospital, Palermo between 2013 and 2022. Incidence, ward distribution, recurrence rate, mortality, and coding rate were considered. The risk of death and recurrence was predicted through multivariable analysis. There were 275 CDIs, 75% hospital-acquired, the median time between admission and diagnosis was 13 days, and the median stay was 21 days. Incidence increased from 0.3 to 5.6% (an 18.7-fold increase) throughout the decade. Only 48.1% of cases were coded in H-SDF. The rate of severe/severe-complicated cases increased 1.9 times. Fidaxomicin was used in 17.1% and 24.7% of cases overall and since 2019. Overall and attributable mortalities were 11.3% and 4.7%, respectively. Median time between diagnosis and death was 11 days, and recurrence rate was 4%. Bezlotoxumab was administered in 64% of recurrences. Multivariable analysis revealed that only hemodialysis was associated with mortality. No statistically significant association in predicting recurrence risk emerged. We advocate for CDI notification to become mandatory and recommend coding CDI diagnosis in H-SDF to aid in infection rate monitoring. Maximum attention should be paid to preventing people on hemodialysis from getting CDI.

Efficacy of bezlotoxumab in preventing recurrence of Clostridioides difficile infection: an Italian multicenter cohort study

OBJECTIVES

Bezlotoxumab (BEZ) is a promising tool for preventing recurrence of Clostridioides difficile infection (rCDI). The aim of the study was to emulate, in a real-world setting, the MODIFY trials in a cohort of participants with multiple risk factors for rCDI treated with BEZ in addition to standard of care (SoC) vs. SoC alone.

METHODS

A multicenter cohort study was conducted including 442 patients with CDI from 2018 to 2022 collected from 18 Italian centers. The main outcome was the 30-days occurrence of rCDI. Secondary outcomes were: (i) all-cause mortality at 30 days (ii) composite outcome (30-day recurrence and/or all-cause death).

RESULTS

rCDI at day 30 occurred in 54 (12%): 11 in the BEZ+SoC group and 43 treated with SoC alone (8% vs. 14%, OR=0.58, 95%CI:0.31-1.09, p=0.09). The difference between BEZ+SoC vs. SoC was statistically significant after controlling for confounding factors (aOR=0.40, 95%CI:018-0.88, p=0.02) and even more using the composite outcome (aOR=0.35, 95%CI:0.17-0.73, p=0.005).

CONCLUSION

Our study confirms the efficacy of BEZ+SoC for the prevention of rCDI and death in a real-world setting. BEZ should be routinely considered among participants at high risk of rCDI regardless of age, type of CDI therapy (vancomycin vs. fidaxomicin) and number of risk factors.

Predicted Bezlotoxumab Exposure in Patients Who Have Received a Hematopoietic Stem Cell Transplant

PURPOSE

Bezlotoxumab is approved for prevention of recurrent Clostridioides (Clostridium) difficile infection (CDI) in adults receiving antibacterial treatment for CDI who are at high risk for recurrent CDI. Previous studies have shown that although serum albumin levels are an important predictor for bezlotoxumab exposure, this has no clinically meaningful impact on efficacy. This pharmacokinetic modeling study assessed whether hematopoietic stem cell transplant (HSCT) recipients, at increased risk of CDI and exhibiting decreased albumin levels within the first month posttransplant, are at risk of clinically relevant reductions in bezlotoxumab exposure.

METHODS

Observed bezlotoxumab concentration-time data pooled from participants in Phase III trials MODIFY I and II (ClinicalTrials.gov identifiers NCT01241552/NCT01513239) and three Phase I studies (PN004, PN005, and PN006) were used to predict bezlotoxumab exposures in two adult post-HSCT populations: A Phase Ib study of posaconazole including allogeneic HSCT recipients (ClinicalTrials.gov identifier NCT01777763; posaconazole-HSCT population); and a Phase III study of fidaxomicin for CDI prophylaxis (ClinicalTrials.gov identifier NCT01691248; fidaxomicin-HSCT population). The bezlotoxumab PK model used the minimum albumin level for each individual in post-HSCT populations to mimic a "worst-case scenario."

FINDINGS

Predicted worst-case bezlotoxumab exposures for the posaconazole-HSCT population (N = 87) were decreased by 10.8% versus bezlotoxumab exposures observed in the pooled Phase III/Phase I data set (N = 1587). No further decrease was predicted for the fidaxomicin-HSCT population (N = 350).

IMPLICATIONS

Based on published population pharmacokinetic data, the predicted decrease in bezlotoxumab exposure in the post-HSCT populations is not expected to have a clinically meaningful effect on bezlotoxumab efficacy at the recommended 10 mg/kg dose. Dose modification is therefore not required in the hypoalbuminemia setting expected post-HSCT. (Clin Ther. 2023;45:XXX-XXX) © 2023 Elsevier HS Journals, Inc.

Real-world Use of Bezlotoxumab and Fecal Microbiota Transplantation for the Treatment of Clostridioides difficile Infection

Background

We aimed to describe the frequency of use and effectiveness of bezlotoxumab (BZX) and fecal microbiota transplantation (FMT) in patients with Clostridioides difficile infection (CDI) in real-world practice.

Methods

This was a retrospective study conducted in a university hospital in which adult patients treated with BZX or FMT from January 2018 to April 2021 were included. The primary objective was to evaluate the effectiveness of BZX and FMT in preventing early (within 8 weeks) and late (within 1 year) CDI recurrences (rCDI). A multivariate analysis of risk factors for early recurrence was performed.

Results

Of 1377 consecutive CDI episodes, 117 (8.5%) received BZX or FMT, with full information available for 100 of the episodes: 51 received BZX, and 49 received FMT. BZX was used mostly in immunosuppressed patients (66.7%) and in first episodes or first recurrences in 70.6% of the cases. FMT was prescribed only in CDI recurrences. Despite the different conditions of the patients, there were no significant differences between BZX and FMT in preventing early rCDI (19.6% vs 24.5%; P = .55) or late rCDI (9.8% vs 18.4%; P = .31). In the multivariate analysis, risk factors for recurrence were presence of ≥2 previous rCDI episodes (odds ratio [OR], 2.90; 95% CI, 1.03-8.63) and use of non-CDI antibiotics (OR, 3.45; 95% CI, 1.24-9.57).

Conclusions

BZX and FMT were infrequently used in real-world practice. Both treatments had similar effectiveness in preventing CDI recurrence despite their application to different populations.

Bezlotoxumab Therapy for Recurrent Clostridium difficile Infection in an Ulcerative Colitis Patient

Background

Clostridium difficile infection (CDI) is the most common infectious cause of nosocomial diarrhea, comprising 10%-20% of all cases. CDI is a significant complication in patients with inflammatory bowel disease (IBD). New monoclonal antibody therapies have emerged as leading treatment options for recurrent CDI (rCDI). Bezlotoxumab, a novel monoclonal antibody, has shown success in decreasing the recurrence rates of patients with rCDI. However, data extrapolating diminished rCDI in patients with concomitant IBD is limited.

Methods

A single infusion of bezlotoxumab @ 10mg/kg was given with fidaxomicin 200mg for 10 days in a patient with rCDI and ulcerative colitis.

Results

The patient's symptoms improved, inflammatory markers normalized, and she has remained asymptomatic for twelve months.

Conclusions

This case supports the findings in the MODIFY I/II trials that Bezlotoxumab is a viable treatment option of rCDI in IBD patients.

Bezlotoxumab in Patients with a Primary Clostridioides difficile Infection: A Literature Review

BACKGROUND

Nowadays, one of the main issues in the management of Clostridioides difficile infection (CDI) is the high rate of recurrences (rCDI), causing increased mortality and higher health care costs.

OBJECTIVES

To assess the available evidence on the use of bezlotoxumab for the prevention of rCDI during a first CDI episode.

METHODS

Published articles on bezlotoxumab during a primary CDI episode were identified through computerized literature searches with the search terms [(bezlotoxumab) AND (CDI) OR (Clostridioides difficile infection)] using PubMed and by reviewing the references of retrieved articles. PubMed was searched until 31 August 2022.

RESULTS

Eighty-eight studies were identified as published from December 2014 to June 2022. Five studies were included in this study, one was a phase III clinical trial and four were sub-analyses or extensions of the previous phase III clinical trial. In the phase III clinical trial, the subgroup analysis on the included primary CDI patients showed that 13.5% of patients receiving bezlotoxumab had an rCDI, whilst 20.9% of patients in the placebo group had an rCDI at the twelve weeks follow-up (absolute difference: -7.4).

CONCLUSIONS

Bezlotoxumab administration during the standard of care antibiotic therapy is effective and safe in reducing the rate of rCDI. Despite its high cost, evidence suggests considering bezlotoxumab in patients with a primary CDI episode. Further studies are needed to assess the benefit in specific subgroups of primary CDI patients and to define the risk factors to guide bezlotoxumab use.

Bezlotoxumab in the treatment of Clostridioides difficile infections: a real-life experience

OBJECTIVE

Following the approval of bezlotoxumab in 2017, studies evaluating its effectiveness in prevention of Clostridioides difficile infection under "real-life" conditions are scarce.

METHODS

We conducted a retrospective study developed in a large tertiary care hospital describing the use and outcomes of patients with Clostridioides difficile infection (CDI) treated with bezlotoxumab.

RESULTS

A total of 16 patients were include, all of whom had an episode of CDI with high probability of recurrence and 14 of them had some kind of immunosuppression. Bezlotoxumab was effective in the prevention of CDI recurrence in 11 of the 14 cases in which follow up was possible, without significant side effects.

CONCLUSIONS

Bezlotoxumab was well tolerated and the incidence of recurrent CDI in a high-risk population for recurrence was only 21.4%.

Bezlotoxumab for Prevention of Recurrent Clostridioides difficile Infection With a Focus on Immunocompromised Patients

OBJECTIVES

Approximately 25% of patients with Clostridioides difficile infection (CDI) will experience recurrence, which is greater in immunocompromised patients. We report experience with an institutional guideline targeting high-risk immunocompromised patients.

METHODS

This was a retrospective cohort of consecutive patients with CDI who met institutional criteria for bezlotoxumab due to high risk for recurrent CDI between June 1, 2017, and November 30, 2018. The primary endpoint of recurrent CDI within 12 weeks was compared between patients who received the standard of care (SoC) plus or minus bezlotoxumab.

RESULTS

Twenty-three patients received bezlotoxumab infusion plus SoC and were compared to 30 SoC patients. 84% of patients were immunocompromised and 54.7% were transplant recipients. The primary endpoint occurred in 13% of bezlotoxumab patients compared to 23.3% of SoC patients. No serious adverse effects were identified.

CONCLUSION

Bezlotoxumab was associated with a meaningful reduction in recurrent CDI in this cohort largely comprising immunocompromised and transplant patients. Larger studies are warranted to evaluate bezlotoxumab in this population.

Real-World Comparison of Bezlotoxumab to Standard of Care Therapy for Prevention of Recurrent Clostridioides difficile Infection in Patients at High Risk for Recurrence

BACKGROUND

Bezlotoxumab (BEZ) is a monoclonal antibody used to prevent recurrent Clostridioides difficile infection (rCDI). This study investigates BEZ effectiveness in relation to rCDI and patient-specific risk factors in a real-world setting.

METHODS

A matched, retrospective cohort study was conducted from 2015 to 2019 to compare BEZ to historical standard of care (SoC) therapy with vancomycin or fidaxomicin. The primary outcome was incidence of 90-day rCDI. Secondary outcomes were incidence of all-cause hospital readmission and all-cause mortality at 90 days, infusion-related reactions, and incidence of heart failure exacerbation. Baseline confounding was addressed using inverse probability of treatment weighting (IPTW).

RESULTS

Overall, 107 participants were included (54 BEZ and 53 SoC). Mean number of prior CDI episodes was 2, median number of risk factors for rCDI was 4, and 28% of participants had severe CDI. Incidence of 90-day rCDI was 11% BEZ vs 43% SoC (P = < .001) and 90-day all-cause readmission was 40% BEZ vs 64% SoC (P = .011). In IPTW-adjusted analyses, BEZ was associated with significantly reduced odds of rCDI (odds ratio [OR], 0.14 [95% confidence interval {CI}: .05-.41]) and all-cause readmission (OR, 0.36 [95% CI: .16-.81]). No safety signals were detected with BEZ use.

CONCLUSIONS

BEZ is effective for the prevention of rCDI and reduction in all-cause hospital readmission for patients at high risk for recurrence, supporting current guideline recommendations.

Effectiveness of Bezlotoxumab for Prevention of Recurrent Clostridioides difficile Infection Among Transplant Recipients

Background

Bezlotoxumab significantly reduces the incidence of recurrent Clostridioides difficile infection (CDI); however, limited data are available in solid organ transplant (SOT) and hematopoietic cell transplant (HCT) recipients.

Methods

We conducted a single-center retrospective analysis comparing recurrent CDI in SOT and HCT recipients receiving standard of care alone (oral vancomycin, fidaxomicin, or metronidazole) or bezlotoxumab plus standard of care. The primary outcome was 90-day incidence of recurrent CDI, and secondary outcomes included 90-day hospital readmission, mortality, and incidence of heart failure exacerbation.

Results

Overall, 94 patients received bezlotoxumab plus standard of care (n = 38) or standard of care alone (n = 56). The mean age was 53 years; patients had a median of 3 prior Clostridioides difficile episodes and 4 risk factors for recurrent infection. Most patients were SOT recipients (76%), with median time to index CDI occurring 2.7 years after transplantation. Ninety-day recurrent CDI occurred in 16% (6/38) in the bezlotoxumab cohort compared to 29% (16/56) in the standard of care cohort (P = .13). Multivariable regression revealed that bezlotoxumab was associated with significantly lower odds of 90-day recurrent CDI (odds ratio, 0.28 [95% confidence interval, .08–.91]). There were no differences in secondary outcomes, and no heart failure exacerbations were observed.

Conclusions

In a cohort of primarily SOT recipients, bezlotoxumab was well tolerated and associated with lower odds of recurrent CDI at 90 days. Larger, prospective trials are needed to confirm these findings among SOT and HCT populations.

Bezlotoxumab for the Prevention of Recurrent Clostridioides difficile Infection: 12-Month Observational Data From the Randomized Phase III Trial, MODIFY II

From Monoclonal Antibodies for C. difficile Therapy II, no participants (n = 0/69) with a sustained clinical cure through 12 weeks following bezlotoxumab infusion experienced recurrent Clostridioides difficile infection (rCDI) after 9 months (versus actoxumab + bezlotoxumab, n = 2/65; versus placebo, n = 1/34). Bezlotoxumab's efficacy appears to be due to prevention rather than delayed onset of rCDI. Clinical Trials Registration. NCT01513239.

Effect of Endogenous Clostridioides difficile Toxin Antibodies on Recurrence of C. difficile Infection

BACKGROUND

Endogenous antibodies (eAbs) against Clostridioides (Clostridium) difficile toxins may protect against recurrence of C. difficile infection (rCDI). This hypothesis was tested using placebo group data from MODIFY (Monoclonal Antibodies for C. difficile Therapy) I and II (NCT01241552 and NCT01513239, respectively), global, randomized phase 3 trials that assessed the efficacy and safety of the antitoxin monoclonal antibodies bezlotoxumab and actoxumab in participants receiving antibiotic therapy for CDI.

METHODS

A placebo infusion (normal saline) was administered on study day 1. Serum samples were collected on day 1, week 4, and week 12, and eAb-A and eAb-B titers were measured by 2 validated electrochemiluminescence immunoassays. Rates of initial clinical cure and rCDI were summarized by eAb titer category (low, medium, high) at each time point.

RESULTS

Serum eAb titers were available from a total of 773 participants. The proportion of participants with high eAb-A and eAb-B titers increased over time. Rates of initial clinical cure were similar across eAb titer categories. There was no correlation between eAb-A titers and rCDI rate at any time point. However, there was a negative correlation between rCDI and eAb-B titer on day 1 and week 4. rCDI occurred in 22% of participants with high eAb-B titers at baseline compared with 35% with low or medium titers (P = .015).

CONCLUSIONS

Higher eAb titers against toxin B, but not toxin A, were associated with protection against rCDI. These data are consistent with the observed efficacy of bezlotoxumab, and lack of efficacy of actoxumab, in the MODIFY trials.

CLINICAL TRIALS REGISTRATION

NCT01241552 and NCT01513239.

Immune response against Clostridioides difficile and translation to therapy

The pathogenesis of Clostridioides difficile infection (CDI) has largely been attributed to the action of two major toxins - A and B. An enhanced systemic humoral immune response against these toxins has been shown to be protective against recurrent CDI. Over the years, fully human monoclonal antibodies against both of these toxins have been developed in an attempt to counter the increasing incidence of recurrent CDI. Clinical trials conducted to evaluate the efficacy of anti-toxin A monoclonal antibody, actoxumab, and anti-toxin B monoclonal antibody, bezlotoxumab, demonstrated that bezlotoxumab substantially lowered the rate of recurrent infection, while actoxumab did not. A significant therapeutic benefit was appreciated in patients with at least one high-risk factor for recurrence, including, age ⩾65 years, immunocompromised state, prior CDI and severe CDI. In light of toxins A and B being immunogenic, vaccine trials are underway with the aim to prevent primary infection.

Real-World Experience with Bezlotoxumab for Prevention of Recurrence of Clostridioides difficile Infection

Bezlotoxumab is marketed for the prevention of recurrent Clostridioides difficile infection (rCDI). Its high cost could be determining its prescription to a different population than that represented in clinical trials. The objective of the study was to verify the effectiveness and safety of bezlotoxumab in preventing rCDI and to investigate factors related to bezlotoxumab failure in the real world. A retrospective, multicentre cohort study of patients treated with bezlotoxumab in Spain was conducted. We compared the characteristics of cohort patients with those of patients treated with bezlotoxumab in the pivotal MODIFY trials. We assessed recurrence rates 12 weeks after completion of treatment against C. difficile, and we analysed the factors associated with bezlotoxumab failure. Ninety-one patients were included in the study. The cohort presented with more risk factors for rCDI than the patients included in the MODIFY trials. Thirteen (14.2%) developed rCDI at 12 weeks of follow-up, and rCDI rates were numerically higher in patients with two or more previous episodes (25%) than in those who had fewer than two previous episodes of C. difficile infection (CDI) (10.4%); p = 0.09. There were no adverse effects attributable to bezlotoxumab. Despite being used in a more compromised population than that represented in clinical trials, we confirm the effectiveness of bezlotoxumab for the prevention of rCDI.

Cost-effectiveness analysis of fecal microbiota transplantation for recurrent Clostridium difficile infection in patients with inflammatory bowel disease

BACKGROUND AND AIM

Inflammatory bowel disease (IBD) patients are at risk for recurrent Clostridium difficile infection (RCDI). We aimed to evaluate the potential health economic and clinical outcomes of four strategies for management of RCDI in IBD patients from the perspective of public health-care provider in Hong Kong.

METHODS

A decision-analytic model was designed to simulate outcomes of adult IBD patients with first RCDI treated with vancomycin, vancomycin plus bezlotoxumab, fidaxomicin and fecal microbiota transplantation (FMT). Model inputs were derived from literature and public data. Primary model outcomes were C. difficile infection (CDI)-related direct medical cost and quality-adjusted life-years (QALYs) loss. Base-case and sensitivity analysis were performed.

RESULTS

Comparing to vancomycin, fidaxomicin and vancomycin plus bezlotoxumab, FMT saved 0.00318, 0.00149 and 0.00306 QALYs and reduced cost by USD3180, USD3790 and USD5514, respectively, in base-case analysis. In probabilistic sensitivity analysis, FMT was cost-saving when comparing to vancomycin, fidaxomicin and vancomycin plus bezlotoxumab by USD3765 (95% confidence interval [CI] 3732-3798; P < 0.001), USD3854 (95%CI 3827-3883; P < 0.001) and USD6501 (95%CI 6465-6,536; P < 0.001), respectively. The QALYs saved by FMT (vs vancomycin) were 0.00386 QALYs (95%CI 0.00384-0.00388; P < 0.001), (vs fidaxomicin) 0.00179 QALYs (95%CI 0.00177-0.00180; P < 0.001) and (vs vancomycin plus bezlotoxumab) 0.00376 QALYs (95%CI 0.00374-0.00378; P < 0.001). FMT was found to save QALYs at lower cost in 99.3% (vs vancomycin), 99.7% (vs fidaxomicin) and 100.0% (vs vancomycin plus bezlotoxumab) of the 10 000 Monte Carlo simulations.

CONCLUSIONS

FMT for IBD patients with RCDI appeared to save both direct medical cost and QALYs when comparing to vancomycin (with or without bezlotoxumab) and fidaxomicin.

Efficacy of Bezlotoxumab in Participants Receiving Metronidazole, Vancomycin, or Fidaxomicin for Treatment of Clostridioides (Clostridium) difficile Infection

Background

In phase 3 MODIFY I/II trials, bezlotoxumab significantly reduced recurrence of Clostridioides (Clostridium) difficile infection (rCDI) over 12 weeks. Choice of CDI antibacterial treatment may affect CDI-related outcomes; therefore, this prespecified analysis assessed if the magnitude of bezlotoxumab-induced rCDI reduction was influenced by the antibiotic administered.

Methods

In MODIFY I/II (NCT01241552/NCT01513239), participants received a single infusion of bezlotoxumab (10 mg/kg) or placebo during anti-CDI treatment. Using pooled data from MODIFY I/II, initial clinical cure (ICC) and rCDI were assessed in metronidazole-, vancomycin-, and fidaxomicin-treated subgroups.

Results

Of 1554 participants in MODIFY I/II, 753 (48.5%) received metronidazole, 745 (47.9%) vancomycin, and 56 (3.6%) fidaxomicin. Fewer participants receiving metronidazole had a prior CDI episode in the previous 6 months (12.9%) or ≥1 risk factor for rCDI (66.0%) vs participants receiving vancomycin (41.2% and 83.6%, respectively) and fidaxomicin (55.4% and 89.3%, respectively). ICC rates were similar in the bezlotoxumab (metronidazole, 81.0%; vancomycin, 78.5%; fidaxomicin, 86.7%) and placebo groups (metronidazole, 81.3%; vancomycin, 79.6%; fidaxomicin, 76.9%). In placebo-treated participants, the rCDI was lower in the metronidazole subgroup vs the vancomycin and fidaxomicin subgroups (metronidazole, 28.0%; vancomycin, 38.4%; fidaxomicin, 35.0%). When analyzed by subsets based on history of CDI, rCDI rates were similar in the metronidazole and vancomycin groups. rCDI rates were lower in all antibiotic subgroups for bezlotoxumab vs placebo (metronidazole: rate difference [RD], –9.7%; 95% confidence interval [CI], –16.4% to –3.1%; vancomycin: RD, –15.4%; 95% CI, –22.7% to –8.0%; fidaxomicin: RD, –11.9%; 95% CI, –38.1% to 14.3%).

Conclusion

Bezlotoxumab reduces rCDI vs placebo in participants receiving metronidazole and vancomycin, with a similar effect size in participants receiving fidaxomicin.

Genetic Association Reveals Protection against Recurrence of Clostridium difficile Infection with Bezlotoxumab Treatment

Clostridium difficile infection is associated with significant clinical morbidity and mortality; antibacterial treatments are effective, but recurrence of C. difficile infection is common. In this genome-wide association study, we explored whether host genetic variability affected treatment responses to bezlotoxumab, a human monoclonal antibody that binds C. difficile toxin B and is indicated for the prevention of recurrent C. difficile infection. Using data from the MODIFY I/II phase 3 clinical trials, we identified three genetic variants associated with reduced rates of C. difficile infection recurrence in bezlotoxumab-treated participants. The effects were most pronounced in participants at high risk of C. difficile infection recurrence. All three variants are located in the extended major histocompatibility complex on chromosome 6, suggesting the involvement of a host-driven immunological mechanism in the prevention of C. difficile infection recurrence.

Bezlotoxumab is a human monoclonal antibody against Clostridium difficile toxin B, indicated to prevent recurrence of C. difficile infection (rCDI) in high-risk adults receiving antibacterial treatment for CDI. An exploratory genome-wide association study investigated whether human genetic variation influences bezlotoxumab response. DNA from 704 participants who achieved initial clinical cure in the phase 3 MODIFY I/II trials was genotyped. Single nucleotide polymorphisms (SNPs) and human leukocyte antigen (HLA) imputation were performed using IMPUTE2 and HIBAG, respectively. A joint test of genotype and genotype-by-treatment interaction in a logistic regression model was used to screen genetic variants associated with response to bezlotoxumab. The SNP rs2516513 and the HLA alleles HLA-DRB1*07:01 and HLA-DQA1*02:01, located in the extended major histocompatibility complex on chromosome 6, were associated with the reduction of rCDI in bezlotoxumab-treated participants. Carriage of a minor allele (homozygous or heterozygous) at any of the identified loci was related to a larger difference in the proportion of participants experiencing rCDI versus placebo; the effect was most prominent in the subgroup at high baseline risk for rCDI. Genotypes associated with an improved bezlotoxumab response showed no association with rCDI in the placebo cohort. These data suggest that a host-driven, immunological mechanism may impact bezlotoxumab response. Trial registration numbers are as follows: NCT01241552 (MODIFY I) and NCT01513239 (MODIFY II).

IMPORTANCEClostridium difficile infection is associated with significant clinical morbidity and mortality; antibacterial treatments are effective, but recurrence of C. difficile infection is common. In this genome-wide association study, we explored whether host genetic variability affected treatment responses to bezlotoxumab, a human monoclonal antibody that binds C. difficile toxin B and is indicated for the prevention of recurrent C. difficile infection. Using data from the MODIFY I/II phase 3 clinical trials, we identified three genetic variants associated with reduced rates of C. difficile infection recurrence in bezlotoxumab-treated participants. The effects were most pronounced in participants at high risk of C. difficile infection recurrence. All three variants are located in the extended major histocompatibility complex on chromosome 6, suggesting the involvement of a host-driven immunological mechanism in the prevention of C. difficile infection recurrence.

Real-world Experience of Bezlotoxumab for Prevention of Clostridioides difficile Infection: A Retrospective Multicenter Cohort Study

Background

Bezlotoxumab is approved for prevention of recurrence of Clostridioides difficile infection (CDI) in adults receiving standard of care (SoC) therapy based on findings from MODIFY clinical trials. However, utilization practices and validation of trial results in the real world are limited.

Methods

Records of patients receiving bezlotoxumab between April 2017 and December 2018 across 34 infusion centers in the United States were retrospectively reviewed. Recurrent CDI (rCDI), defined as diarrhea lasting ≥2 days resulting in treatment, was assessed 90 days postbezlotoxumab.

Results

The study cohort included 200 patients (median age, 70 years; 66% female; median Charlson comorbidity index, 5), of whom 86% (n = 173) had prior CDI episodes and 79% (n = 158) had ≥2 risk factors for rCDI. SoC antibiotics included vancomycin (n = 137, 68%), fidaxomicin (n = 60, 30%), and metronidazole (n = 3, 2%). Median time from C. difficile stool test to bezlotoxumab and initiation of SoC to bezlotoxumab were 15 days and 11 days, respectively. Within 90 days, 31 of 195 patients (15.9%) experienced rCDI, which corresponds to a success rate of 84.1%. Patients with ≥2 CDI recurrences prebezlotoxumab had a higher risk of subsequent rCDI compared with those with 1 recurrence or primary CDI (hazard ratio, 2.77; 95% confidence interval, 1.14–6.76; P = .025).

Conclusions

This real-world multicenter study demonstrated successful prevention of rCDI with bezlotoxumab comparable to clinical trial results regardless of type of SoC and timing of infusion. Multiple prior CDI recurrences were associated with a higher risk of subsequent rCDI, supporting the use of bezlotoxumab earlier in the disease course.

Comparing the efficacy and safety of faecal microbiota transplantation with bezlotoxumab in reducing the risk of recurrent Clostridium difficile infections: a systematic review and Bayesian network meta-analysis of randomised controlled trials

OBJECTIVES

The risk of recurrent Clostridium difficile infections (RCDIs) is high when treated with standard antibiotics therapy (SAT) alone. It is suggested that the addition of faecal microbiota transplantation (FMT) or bezlotoxumab after SAT reduces the risk of RCDI. In the absence of head-to-head randomised controlled trials (RCTs), this review attempts to compare the efficacy and safety of bezlotoxumab with FMT in reducing the risk of RCDI in hospitalised patients.

DESIGN

A systematic review and Bayesian network meta-analysis.

DATA SOURCE

A comprehensive search from inception to 30 February 2019 was conducted in four databases (Medline/PubMed, Embase, Scopus, ClinicalTrials.gov).

ELIGIBILITY CRITERIA

RCTs reporting the resolution of diarrhoea associated with RCDI without relapse for at least 60 days after the end of treatments as the primary outcome.

DATA EXTRACTION AND SYNTHESIS

We extracted author, year of publication, study design and binomial data that represented the resolution of diarrhoea or adverse events of monoclonal antibodies and FMT infusion. Random-effects models were used for resolution rate of RCDI and adverse events. The Cochrane Risk of Bias tool was used to assess the quality of included RCTs.

RESULTS

Out of 1003 articles identified, seven RCTs involving 3043 patients contributed to the review. No difference was reported between single or multiple infusions of FMT and bezlotoxumab in resolving RCDI, (OR 1.53, 95% credible interval (CrI) 0.39 to 5.16) and (OR 2.86, 95% CrI 1.29 to 6.57), respectively. Patients treated with SAT alone or bezlotoxumab with SAT showed significantly lower rates of diarrhoea than FMT (OR 0, 95% CrI 0 to 0.09) and (OR 0, 95% CrI 0 to 0.19), respectively. There was no difference in terms of other adverse events.

CONCLUSIONS

This is the first network meta-analysis that has compared the recently Food and Drug Administration-approved monoclonal antibody bezlotoxumab with FMT for resolving RCDI. The quality of the included RCTs was variable. The findings of this study suggested no difference between single or multiple infusions of FMT and bezlotoxumab. However, FMT was associated with a higher rate of non-serious diarrhoea as opposed to SAT used alone or in combination with bezlotoxumab.

Cost-effectiveness of Bezlotoxumab Compared With Placebo for the Prevention of Recurrent Clostridium difficile Infection

Background

Clostridium difficile infection (CDI) is the most commonly recognized cause of recurrent diarrhea. Bezlotoxumab, administered concurrently with antibiotics directed against C. difficile (standard of care [SoC]), has been shown to reduce the recurrence of CDI, compared with SoC alone. This study aimed to assess the cost-effectiveness of bezlotoxumab administered concurrently with SoC, compared with SoC alone, in subgroups of patients at risk of recurrence of CDI.

Methods

A computer-based Markov health state transition model was designed to track the natural history of patients infected with CDI. A cohort of patients entered the model with either a mild/moderate or severe CDI episode, and were treated with SoC antibiotics together with either bezlotoxumab or placebo. The cohort was followed over a lifetime horizon, and costs and utilities for the various health states were used to estimate incremental cost-effectiveness ratios (ICERs). Both deterministic and probabilistic sensitivity analyses were used to test the robustness of the results.

Results

The cost-effectiveness model showed that, compared with placebo, bezlotoxumab was associated with 0.12 quality-adjusted life-years (QALYs) gained and was cost-effective in preventing CDI recurrences in the entire trial population, with an ICER of $19824/QALY gained. Compared with placebo, bezlotoxumab was also cost-effective in the subgroups of patients aged ≥65 years (ICER of $15298/QALY), immunocompromised patients (ICER of $12597/QALY), and patients with severe CDI (ICER of $21430/QALY).

Conclusions

Model-based results demonstrated that bezlotoxumab was cost-effective in the prevention of recurrent CDI compared with placebo, among patients receiving SoC antibiotics for treatment of CDI.

Population Pharmacokinetics and Pharmacodynamics of Bezlotoxumab in Adults with Primary and Recurrent Clostridium difficile Infection

The fully human monoclonal antibody bezlotoxumab is indicated for preventing the recurrence of Clostridioides difficile (formerly Clostridium difficile) infection (CDI) in adults who receive antibacterial treatment for CDI and who are at high risk for a CDI recurrence. The efficacy and safety of 10-mg/kg of body weight bezlotoxumab were demonstrated in two phase 3 trials: the MODIFY I (ClinicalTrials.gov registration number NCT01241552) and MODIFY II (ClinicalTrials.gov registration number NCT01513239) trials. Here, a population pharmacokinetic (popPK) analysis, performed using data from the MODIFY I and II trials (n = 1,515) and from three phase 1 trials (n = 72) to characterize bezlotoxumab pharmacokinetics (PK) in phase 3 clinical trial participants and in healthy subjects, is reported. A stepwise covariate search was conducted to identify factors influencing PK. Post hoc-estimated bezlotoxumab exposures from the popPK model were used to conduct an exposure-response analysis for CDI recurrence. Bezlotoxumab PK were described by a two-compartment model with linear elimination and allometric scaling for clearance and the volume of distribution by body weight. Although the final popPK model included gender, ethnicity (Japanese descent), race (black versus nonblack), and albumin level as significant covariates, the impact of these factors was not clinically meaningful, based on the totality of the PK and clinical experience. Exposure-response analysis of CDI recurrence demonstrated a similar low rate of CDI recurrence over the entire range of exposures achieved in the phase 3 trials, indicating that exposures were on the maximal response plateau of the exposure-response curve. Overall, the analyses confirmed the appropriateness of the 10-mg/kg dose across the phase 3 trial population with no dose adjustments necessary over a broad demographic background.

Doctor, my patient has CDI and should continue to receive antibiotics. The (unresolved) risk of recurrent CDI

Recurrence rate ranges from 12% to 40% of all cases of Clostridium difficile infection (CDI) and proposes an exceptional clinical challenge. Conventionally, treatment options of CDI have been limited to regimes of established antibiotics (eg, pulsed/tapered vancomycin) or "improvised" alternative antibiotics (eg. teicoplanin, tigecycline, nitazoxanide or rifaximin) occasionally even in combination, but faecal microbiota transplantation is emerging as a useful and quite safe alternative. In recent years, promising new strategies have emerged for effective prevention of recurrent CDI (rCDI) including new an-timicrobials (eg, fidaxomicin) and monoclonal antibodies (eg, bezlotoxumab). Despite promising progress in this area, difficulties remain for making the best use of these resources due to uncertainty over patient selection. This positioning review describes the current epidemiology of rCDI, its clinical impact and risk factors, some of the measures used for treating and preventing rCDI, and some of the emerging treatment options. It then describes some of the barriers that need to be overcome.

Bezlotoxumab for the prevention of Clostridium difficile infection: a review of current evidence and safety profile

Clostridium difficile infection (CDI) is a leading nosocomial disease estimated to cause nearly half a million cases in the United States annually. Recurrent CDI (rCDI) affects ~25% of patients after completion of standard of care therapy and is associated with substantial health care costs and a negative impact on patient's overall markers of quality of life. Bezlotoxumab is the first of its kind monoclonal antibody directed against C. difficile toxin B and indicated for prevention of rCDI in at-risk patients. For the present review, we assessed English-language studies evaluating the clinical efficacy, safety, and pharmacokinetics of bezlotoxumab in humans. Relevant studies were obtained through PubMed, Embase, Cochrane database library, Web of Science, and clinicaltrials.gov. Overall, bezlotoxumab demonstrated a 40% relative reduction rate (absolute rate reduction of ~10%) and a number needed to treat of 10 patients with a favorable safety profile. Special populations, including the elderly, immunocompromised, and patients with end-stage renal disease were evaluated in post hoc analyses with a similarly favorable reduction in rCDI. This review presents and interprets the most recent safety data and the clinical application of bezlotoxumab, highlighting specific high-risk patient populations.

New FDA approved antibacterial drugs: 2015-2017

Increasing bacterial resistance to antibiotics is a worldwide ongoing issue. Urgent need for new antibacterial agents has resulted in significant research efforts, with new molecules proposed for use in clinical practice. However, as highlighted by many groups this process does not have an optimal rhythm and efficacy, to fully combat highly adaptive germs, particularly in the intensive care units. This review focuses on the last three years of novel FDA approved antibacterial agents (2015-2017): ceftazidime/avibactam, obiltoxaximab, bezlotoxu-mab, delafloxacin, meropenem/vaborbactam, ozenoxacin. Ceftazidime/avibactam and meropenem/ vaborbactam are new players in the field of resistant bacteria treatment. Ceftazidime/avibactam is validated in selected patients with complicated urinary or intra-abdominal infections, hospital and ventilator-associated pneumonia. Meropenem/ vaborbactam gained approval for the cases of complicated urinary tract infections. Other potential indications are under investigation, widened and validated by future studies. Obiltoxaximab is a monoclonal antibody that can be used in the prevention and treatment of inhalational anthrax. Bezlotoxumab monoclonal antibody is an useful and specific tool for the management of recurrent Clostridium difficile infection. Delafloxacin is approved for patients with acute skin or skin structure infections. Despite recent progress, it is imperative to continue the development of new antibiotic drugs and new strategies to counteract resistance to antibiotics.

Actoxumab + bezlotoxumab combination: what promise for Clostridium difficile treatment?

INTRODUCTION

Clostridium difficile infection (CDI) is the most common healthcare-associated infection worldwide. As standard CDI antibiotic therapies can result in unacceptably high recurrence rates, novel therapeutic strategies for CDI are necessary. A recently emerged immunological therapy is a monoclonal antibody against C. difficile toxin B. Areas covered: In this review, the authors summarize the available pharmacological, preclinical, and clinical data for the CDI treatment based on anti-toxin A (actoxumab) and anti-toxin B (bezlotoxumab) human monoclonal antibodies (HuMabs), and discuss about the potentiality of a therapy that includes HuMab combined administration for CDI. Expert opinion: Although only bezlotoxumab is indicated to reduce recurrence of CDI, experimental studies using a combination of HuMabs actoxumab and bezlotoxumab have shown that bolstering the host immune response against both the C. difficile toxins may be effective in primary and secondary CDI prevention. Besides neutralizing both the key virulence factors, combination of two HuMabs could potentially offer an advantage for a yet to emerge C. difficile strain, which is a steady threat for patients at high risk of CDI. However, as actoxumab development was halted, passive immunotherapy with actoxumab/bezlotoxumab is actually impracticable. Future research will be needed to assess HuMab combination as a therapeutic strategy in clinical and microbiological cure of CDI.

Recent Progress for the Effective Prevention and Treatment of Recurrent Clostridium difficile Infection

Recurrence occurs in approximately 25% of all cases of Clostridium difficile infection (CDI) and poses a unique clinical challenge. Traditionally, treatment options of CDI have been limited to regimes of established antibiotics (eg, pulsed/tapered vancomycin) but faecal transplantation is emerging as a useful alternative. In recent years, promising new strategies have emerged for effective prevention of recurrent CDI (rCDI) including new antimicrobials (eg, fidaxomicin) and monoclonal antibodies (eg, bezlotoxumab). Despite promising progress in this area, obstacles remain for making the best use of these resources due to uncertainty over patient selection. This commentary describes the current epidemiology of rCDI, its clinical impact and risk factors, some of the measures used for treating and preventing rCDI, and some of the emerging treatment options. It then describes some of the obstacles that need to be overcome.

Bezlotoxumab: an emerging monoclonal antibody therapy for prevention of recurrent Clostridium difficile infection

Clostridium difficile infection (CDI) is the most common health care-acquired infection associated with high hospital expenditures. The incidence of subsequent recurrent CDI increases with prior episodes of CDI, 15%–35% risk after primary CDI to 35%–65% risk after the first recurrent episode. Recurrent CDI is one of the most challenging and a very difficult to treat infections. Standard guidelines provide recommendations on treatment of primary CDI. However, treatment choices for recurrent CDI are limited. Recent research studies have focused on the discovery of newer alternatives for prevention of recurrent CDI targeting prime virulence factors involved in C. difficile pathogenesis. Bezlotoxumab is a human monoclonal antibody directed against C. difficile toxin B. Multiple in vitro and in vivo animal studies have demonstrated direct binding of bezlotoxumab to C. difficile toxin B preventing intestinal epithelial damage and colitis. Furthermore, this monoclonal antibody mediates early reconstitution of gut microbiota preventing risk of recurrent CDI. Randomized placebo-controlled trials showed concomitant administration of a single intravenous dose of 10 mg/kg of bezlotoxumab, in patients on standard-of-care therapy for CDI, had no substantial effect on clinical cure rates but significantly reduced the incidence of recurrent CDI (~40%). It shows efficacy against multiple strains, including the epidemic BI/NAP1/027 strain. Bezlotoxumab is a US Food and Drug administration-approved, safe and well-tolerated drug with low risk of serious adverse events and drug–drug interactions. Bezlotoxumab has emerged as a novel dynamic adjunctive therapy for prevention of recurrent CDI. Further studies on real-world experience with bezlotoxumab and its impact in reducing rates of recurrent CDI are needed.

Bezlotoxumab for the prevention of Clostridium difficile recurrence

Clostridium difficile infection is a major economic and clinical burden, due to its high frequency of recurrence. Currently recommended treatments are not efficient for prevention and may contribute to the risk of recurrent infection. In recent years, research has focused on strategies to lessen this risk. Bezlotoxumab is a monoclonal antibody that prevents recurrences of C. difficile infection through the antagonism of toxin B. Areas covered: In this review, the authors discuss the burden of C. difficile infection and its recurrences, the mechanisms underlying the recurrences, and current C. difficile treatments. They subsequently analyze the strategic therapeutic rationale for bezlotoxumab use, as well as the supporting clinical evidence. Expert opinion: Bezlotoxumab is an attractive solution for reducing the unacceptable level of recurrence that occurs with the currently recommended C. difficile treatments and other alternative therapies under consideration. Even though bezlotoxumab has not been tested in large-scale trials exclusively in cases of already established recurrent C.difficile infection (rCDI), it has an advantage over current treatments in that it does not interfere with the patient's gut flora while directly neutralizing the key virulence factor. Although cost remains an important factor against its widespread use, simpler administration, fewer side-effects, and better social acceptability justify its consideration for treating rCDI.

Clostridium difficile infection in the elderly: an update on management

The burden of Clostridium difficile infection (CDI) is profound and growing. CDI now represents a common cause of health care–associated diarrhea, and is associated with significant morbidity, mortality, and health care costs. CDI disproportionally affects the elderly, possibly explained by the following risk factors: age-related impairment of the immune system, increasing antibiotic utilization, and frequent health care exposure. In the USA, recent epidemiological studies estimate that two out of every three health care–associated CDIs occur in patients 65 years or older. Additionally, the elderly are at higher risk for recurrent CDI. Existing therapeutic options include metronidazole, oral vancomycin, and fidaxomicin. Choice of agent depends on disease severity, history of recurrence, and, increasingly, the drug cost. Bezlotoxumab, a recently approved monoclonal antibody targeting C. difficile toxin B, offers an exciting advancement into immunologic therapies. Similarly, fecal microbiota transplantation is gaining popularity as an effective option mainly for recurrent CDI. The challenge of decreasing CDI burden in the elderly involves adopting preventative strategies, optimizing initial treatment, and decreasing the risk of recurrence. Expanded strategies are certainly needed to improve outcomes in this high-risk population. This review considers available data from prospective and retrospective studies as well as case reports to illustrate the merits and gaps in care related to the management of CDI in the elderly.

Bezlotoxumab: A Novel Agent for the Prevention of Recurrent Clostridium difficile Infection

During the past decade, the incidence and severity of Clostridium difficile infection (CDI) have significantly increased, leading to a rise in CDI-associated hospitalizations, health care costs, and mortality. Although treatment options exist for CDI, recurrence is frequent following treatment. Furthermore, patients with at least one CDI recurrence are at an increased risk of developing additional recurrences. A novel approach to the prevention of recurrent CDI is the use of monoclonal antibodies directed against the toxins responsible for CDI as an adjunct to antibiotic treatment. Bezlotoxumab, a human monoclonal antibody that binds and neutralizes C. difficile toxin B, is the first therapeutic agent to receive United States Food and Drug Administration approval for the prevention of CDI recurrence. Clinical studies have demonstrated superior efficacy of bezlotoxumab in adults receiving antibiotic therapy for CDI compared with antibiotic therapy alone for the prevention of CDI recurrence. Bezlotoxumab was well tolerated in clinical trials, with the most common adverse effects being nausea, vomiting, fatigue, pyrexia, headache, and diarrhea. The demonstrated efficacy, safety, and characteristics of bezlotoxumab present an advance in prevention of CDI recurrence.

Bezlotoxumab: Could This be the Answer for Clostridium difficile Recurrence?

OBJECTIVE

To review the pharmacology, pharmacokinetics, efficacy, safety, and place in therapy of bezlotoxumab (BEZ), a novel monoclonal antibody against Clostridium difficile toxin B.

DATA SOURCES

A PubMed search was conducted for data between 1946 and April 2017 using MeSH terms bezlotoxumab, MK-6072, or MDX-1388 alone and the terms Clostridium difficile combined with monoclonal antibody or antitoxin.

STUDY SELECTION AND DATA EXTRACTION

The literature search was limited to English-language studies that described clinical efficacy, safety, and pharmacokinetics in humans and animals. Abstracts featuring prepublished data were also evaluated for inclusion.

DATA SYNTHESIS

BEZ is indicated for adult patients receiving standard-of-care (SoC) antibiotics for C difficile infection (CDI) to prevent future recurrence. Two phase III trials-MODIFY I (n = 1452) and MODIFY II (n = 1203)-demonstrated a 40% relative reduction in recurrent CDI (rCDI) with BEZ compared with placebo (16.5% vs 26.6%, P < 0.0001). The most common adverse drug events associated with BEZ were mild to moderate infusion-related reactions (10.3%).

CONCLUSIONS

In patients treated with SoC antibiotics, BEZ is effective in decreasing rCDI. BEZ has no apparent effect on treatment of an initial CDI episode. In light of increasing rates of CDI, BEZ is a promising option for preventing recurrent episodes. The greatest benefit has been demonstrated in high-risk patients, though the targeted patient population is yet to be defined.