Vancomycin, metronidazole, or tolevamer for Clostridium difficile infection: results from two multinational, randomized, controlled trials.

BACKGROUND: Clostridium difficile infection (CDI) is a common complication of antibiotic therapy that is treated with antibiotics, contributing to ongoing disruption of the colonic microbiota and CDI recurrence. Two multinational trials were conducted to compare the efficacy of tolevamer, a nonantibiotic, toxin-binding polymer, with vancomycin and metronidazole. METHODS: Patients with CDI were randomly assigned in a 2:1:1 ratio to oral tolevamer 9 g (loading dose) followed by 3 g every 8 hours for 14 days, vancomycin 125 mg every 6 hours for 10 days, or metronidazole 375 mg every 6 hours for 10 days. The primary endpoint was clinical success, defined as resolution of diarrhea and absence of severe abdominal discomfort for more than 2 consecutive days including day 10. RESULTS: In a pooled analysis, 563 patients received tolevamer, 289 received metronidazole, and 266 received vancomycin. Clinical success of tolevamer was inferior to both metronidazole and vancomycin (P < .001), and metronidazole was inferior to vancomycin (P = .02; 44.2% [n = 534], 72.7% [n = 278], and 81.1% [n = 259], respectively). Clinical success in patients with severe CDI who received metronidazole was 66.3% compared with vancomycin, which was 78.5%. (P = .059). A post-hoc multivariate analysis that excluded tolevamer found 3 factors that were strongly associated with clinical success: vancomycin treatment, treatment-naive status, and mild or moderate CDI severity. Adverse events were similar among the treatment groups. CONCLUSIONS: Tolevamer was inferior to antibiotic treatment of CDI, and metronidazole was inferior to vancomycin. Trial Registration. clinicaltrials.gov NCT00106509 and NCT00196794.

Distribution of Clostridium difficile strains from a North American, European and Australian trial of treatment for C. difficile infections: 2005-2007.

Clostridium difficile is a widely distributed pathogen with multiple strain types as determined by restriction endonuclease analysis (REA) and by PCR ribotyping, two well-characterized typing systems. In this study, REA typing was performed on 894C. difficile isolates from patients enrolled from 16 countries on three continents in two large, recently conducted clinical treatment trials of C. difficile infection. REA group BI (Ribotype 027) isolates were the most common strains identified and were widely distributed throughout North America, but restricted to three of thirteen countries in Europe. REA group J (Ribotype 001) isolates were the most common strains identified in Europe and non-specific REA groups (historically less frequent) were the most common strains identified in Australia. REA groups BI, J, G and CF correlated with specific PCR ribotypes whereas more than one ribotype was found within REA groups Y, BK, and K. International surveillance of C. difficile strains is important to document the changing epidemiology of this enteric pathogen that continues to cause healthcare facility outbreaks and sporadic infections in other settings.

A new formulation of tolevamer, a novel nonantibiotic polymer, is safe and well-tolerated in healthy volunteers: a randomized phase I trial.

AIMS: To evaluate the safety and tolerability of a new oral solution formulation of tolevamer potassium sodium, a nonantibiotic polymer that binds Clostridium difficile toxins A and B. METHODS: This phase 1 randomized, double-blind, placebo-controlled study evaluated four doses of tolevamer potassium sodium in 40 healthy volunteers using a sequential dose escalation paradigm and doses of 6, 9, 12 and 15 g day(-1) for 9 days. Within each 10 patient cohort, eight patients received active treatment and two matching placebo. Placebo subjects were pooled to provide eight per arm. All subjects received three times daily dosing on days 2-8 as well as a loading dose (a single dose equal to the total daily dose) either on day 1 or day 9. RESULTS: All 40 subjects completed the study per protocol. Treatment-emergent adverse events (TEAEs) were generally mild, transient, and resolved without sequelae. There were no serious AEs or deaths. There was no relationship detected between dose and the incidence of TEAEs, whether drug-related (all gastrointestinal disorders) or not. No clinically significant changes in laboratory parameters, including serum and urinary potassium concentrations, vital signs, and results of physical examination, were observed. A small but statistically significant reduction in 24 h urine potassium excretion was seen in the 15 g day(-1) dose group, and on day 10 in the 6 g day(-1) group. CONCLUSIONS: Tolevamer oral solution administered for 9 days at total daily doses up to 15 g, with loading doses of up to 15 g, was generally safe and well-tolerated in healthy volunteers.

The emerging infectious challenge of clostridium difficile-associated disease in Massachusetts hospitals: clinical and economic consequences.

OBJECTIVE: To estimate the clinical and economic burden of Clostridium difficile-associated disease (CDAD) in Massachusetts over 2 years. DESIGN: A retrospective analysis of Massachusetts hospital discharge data from 1999-2003 was conducted. Cases of CDAD in 2000 were identified using code 008.45 from the International Classification of Diseases, Ninth Revision, Clinical Modification; patients were excluded if they had a hospitalization in the prior year during which a diagnosis of CDAD was recorded. Hospitalizations for CDAD during 2001 and 2002 were examined. For primary case patients (ie, those for which CDAD was the principal diagnosis), all inpatient costs were deemed to be related, whereas for secondary case patients, all-patient refined diagnosis-related group assignment, case severity level, and length of stay (LOS) were used to calculate incremental costs attributable to CDAD. Costs were adjusted to the national level and reported in 2005 US dollars. RESULTS: The CDAD cohort consisted of 3,692 patients; 59% were women, and the mean age was 70 years. This group represented 1% of all patients hospitalized in Massachusetts in 2000 (96% of hospitals treated at least 1 case; range, 1-257 cases). Of patients who received a first hospital diagnosis of CDAD in 2000, a total of 28% were primary case patients; their mean LOS was 6.4 days, and the mean cost per stay was $10,212. For secondary case patients, the mean CDAD-related incremental LOS was 2.95 days, and the mean incremental cost per stay was $13,675 per patient. Of patients with CDAD who survived their index stay in 2000, a total of 455 (14%) had at least 1 readmission for CDAD within the subsequent 2 years (mean number of readmissions, 1.4 per patient; range, 1-7 readmissions), with a mean time to first readmission of 3 months. Over 2 years, a total of 55,380 inpatient-days and $51.2 million were consumed by CDAD management. CONCLUSION: CDAD is widespread in Massachusetts hospitals. Rehospitalization with CDAD, if it occurs, generally happens within a few months and happens multiple times for some patients. Based on this study's findings, a conservative estimate of the annual US cost for CDAD management is $3.2 billion dollars.

Tolevamer, a novel nonantibiotic polymer, compared with vancomycin in the treatment of mild to moderately severe Clostridium difficile-associated diarrhea.

BACKGROUND: Current antibiotic therapies for Clostridium difficile-associated diarrhea have limitations, including progression to severe disease, recurrent C. difficile-associated diarrhea, and selection for nosocomial pathogens. Tolevamer, a soluble, high-molecular weight, anionic polymer that binds C. difficile toxins A and B is a unique nonantibiotic treatment option. METHODS: In this 3-arm, multicenter, randomized, double-blind, active-controlled, parallel-design phase II study, patients with mild to moderately severe C. difficile-associated diarrhea were randomized to receive 3 g of tolevamer per day (n = 97), 6 g of tolevamer per day (n = 95), or 500 mg of vancomycin per day (n = 97). The primary efficacy parameter was time to resolution of diarrhea, defined as the first day of 2 consecutive days when the patient had hard or formed stools (any number) or < or = 2 stools of loose or watery consistency. RESULTS: In the per-protocol study population, resolution of diarrhea was achieved in 48 (67%) of 72 patients receiving 3 g of tolevamer per day (median time to resolution of diarrhea, 4.0 days; 95% confidence interval, 2.0-6.0 days), in 58 (83%) of 70 patients receiving 6 g of tolevamer per day (median time to resolution of diarrhea, 2.5 days; 95% confidence interval, 2.0-3.0 days), and in 73 (91%) of 80 patients receiving vancomycin (median time to resolution of diarrhea, 2.0 days; 95% confidence interval, 1.0-3.0 days). Tolevamer administered at a dosage of 6 g per day was found to be noninferior to vancomycin administered at a dosage of 500 mg per day with regard to time to resolution of diarrhea (P = .02) and was associated with a trend toward a lower recurrence rate. Tolevamer was well tolerated but was associated with an increased risk of hypokalemia. CONCLUSIONS: Tolevamer, a novel polystyrene binder of C. difficile toxins A and B, effectively treats mild to moderate C. difficile diarrhea and merits further clinical development.

Absorption of colesevelam hydrochloride in healthy volunteers.

OBJECTIVE: To assess whether colesevelam hydrochloride is absorbed in healthy volunteers. METHODS: A single-center, open-label, radiolabeled study was performed with 16 healthy volunteers. Subjects were administered non-radiolabeled colesevelam hydrochloride 1.9 g twice daily for 4 weeks, followed by a single dose of [14C]-colesevelam 2.4 g (480 pCi). These subjects continued to receive non-radioactive colesevelam 1.9 g twice daily for 4 days after administration of the radiolabeled dose. Blood, urine, and feces were collected immediately prior to administration of [14C]-colesevelam and at specified intervals after administration. The whole-blood equivalent concentration of colesevelam was calculated using data collected throughout the 96 hours following radiolabeled drug administration. The proportion of [14C]-colesevelam excreted through urine or feces was calculated based on the amount of radioactivity recovered up to 216 hours after the radiolabeled dose. RESULTS: The mean cumulative total recovery of [14C]-colesevelam in urine and feces was 0.05% and 74%, respectively. Excluding 2 subjects for whom cumulative recovery was <25%, the mean cumulative fecal recovery was 82%. The mean maximum whole-blood equivalent concentration of colesevelam was 0.165+/-0.10 microg equiv/g 72 hours after administration of [14C]-colesevelam, which was estimated to be 0.04% of the administered dose. All blood samples contained <4 times the number of background counts (dpm). CONCLUSIONS: The cumulative recovery data in urine and feces are consistent with the conclusion that colesevelam is not absorbed and is excreted entirely through the gastrointestinal system.