Loracarbef (LY163892) versus amoxicillin-clavulanate in the treatment of bacterial acute otitis media with effusion

Comparison of study designs for acute otitis media trials

BACKGROUND

A framework for evaluating the efficacy of antibiotics in development as well as those currently approved for acute otitis media (AOM) is needed.

OBJECTIVE

Review strengths and limitations of various antibiotic trial designs and their outcome measures.

METHODS

A review of 157 published trials involving 36,710 subjects for the treatment of AOM.

RESULTS

AOM trials have three designs: (1) clinical, clinical diagnosis and assessment of outcomes; (2) single tympanocentesis, microbiologic diagnosis (by middle ear fluid culture) and clinical assessment of outcomes; and (3) double tympanocentesis, microbiologic diagnosis and microbiologic outcome assessment. Identifiable strengths and limitations of each design are reviewed. Case definitions for entry of children in trials of AOM vary widely. The lack of stringent diagnostic criteria in a clinical design allows for inclusion of a significant proportion of children with a non-bacterial etiology (i.e., viral AOM or otitis media with effusion). Tympanocentesis increases diagnostic accuracy at study entry; however, the procedure is confounding because of its potentially therapeutic benefit and the procedure is not performed in a uniform manner. A second tympanocentesis allows a high sensitivity to detect microbiologic eradication, but it does not correlate with clinical outcomes in half of the cases. The timing of outcome assessment also varies widely among trials.

CONCLUSIONS

Improved clinical diagnosis criteria for AOM are needed to enhance specificity; emphasis on a bulging tympanic membrane has the best evidence base. Tympanocentesis within study designs has merits. At study entry it assures diagnostic accuracy but may alter outcomes and it is useful to document microbiologic outcomes but lacks specificity for clinical outcomes. For all designs, test of cure assessment 2-7 days after completion of therapy seems most appropriate.

Otitis media

Bacterial pathogens are isolated from middle ear fluid in up to 90% of children with acute otitis media (OM). Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis predominate. Acute OM can be classified as uncomplicated, persistent, recurrent or chronic. Patient age, symptom severity, prior treatment history and exposure through day-care attendance in children influences pathogen distribution, antimicrobial susceptibility and anticipated clinical and microbiological responses to empirical and pathogen-directed therapies. The natural history of acute OM without intervention is favourable. However, meta-analysis of clinical trials shows an improvement in symptom and middle ear effusion resolution with antimicrobials. Aminopenicillins, cephalosporins and macrolides are often selected as therapy for acute OM. The various agents have differing activity against acute OM pathogens, particularly organisms with resistance mechanisms and they differ in dosing schedule, side effects and compliance enhancing factors. Consideration should be given to pharmacokinetic and pharmacodynamic principles in antibiotic selection. Selection criteria include antibiotic activity against drug-resistant S. pneumoniae and efficacy against beta-lactamase-producing Gram-negative organisms. The necessary duration of treatment for acute OM varies according to multiple factors, including local preferences, but there is growing, compelling data to support short-course therapy. Tympanocentesis has been endorsed in various guidelines as a diagnostic and therapeutic procedure. Best-practice for management of acute OM continues to advocate antibiotic therapy with careful, accurate diagnosis and consideration of the major pathogens and their mechanisms of resistance.

Randomized clinical trial of soy formula with and without added fiber in antibiotic-induced diarrhea

OBJECTIVE

The objective of this study was to examine the effects of soy formulas with and without added soy fiber in children who developed diarrhea while receiving antibiotics.

DESIGN

In a masked, randomized parallel study, older infants and toddlers were fed commercial soy formulas with or without added soy fiber for 10 days on occurrence of diarrhea during the administration of antibiotics. Subjects were stratified by feeding (formula versus cow's milk). The primary variables were duration of diarrhea, stool characteristics, and intake. Secondary variables were weight and spit-up.

RESULTS

All 45 children who completed the 10-day study received >30% of their caloric intake from formula. Fiber intake from other foods did not differ between groups and averaged 0.5 g/day. Total median fiber intake of the group fed the formula with added fiber was 6.53 g/day. The mean duration of diarrhea was 25.1 +/- 5.2 hours for children fed the formula with added fiber and 51.6 +/- 10.7 hours for those fed the regular formula (P =.0013).

CONCLUSION

The duration of antibiotic-induced diarrhea in children fed the soy formula with added soy fiber was significantly reduced.

Evidence assessment of management of acute otitis media: I. The role of antibiotics in treatment of uncomplicated acute otitis media

CONTEXT

In 1995, >5 million episodes of acute otitis media (AOM) accounted for $3 billion in health care expenditures.

OBJECTIVES

To synthesize the literature on the natural history of AOM, the effectiveness of antibiotic treatment in uncomplicated AOM, and the relative effectiveness of specific antibiotic regimens.

DATA SOURCES

Seven electronic databases for articles published between 1966 and March 1999 and reference lists in proceedings, published articles, reports, and guidelines.

STUDY SELECTION

Two physicians independently assessed each article. Studies addressing AOM in children 4 weeks to 18 years old were included; those addressing children with immunodeficiencies or craniofacial abnormalities were excluded. Randomized, controlled trials (RCTs) were used to assess antibiotic effectiveness, and RCTs and cohort studies were used to assess the natural history of AOM. Among the 3491 citations identified, 80 (2.3%) met our inclusion criteria.

DATA EXTRACTION

Two physicians independently abstracted data and assessed the quality of studies using a validated scale for RCTs and 8 quality components for cohort studies.

DATA SYNTHESIS

Random-effects estimates of pooled absolute rate differences of outcomes were derived, and heterogeneity of both the rates and rate differences was assessed. Children with AOM not treated with antibiotics experienced a 1- to 7-day clinical failure rate of 19% (95% confidence interval: 0.10-0.28) and few suppurative complications. When patients were treated with amoxicillin, the 2- to 7-day clinical failure rate was reduced to 7%, a 12% (95% confidence interval: 0.04-0.20) reduction. Adverse effects, primarily gastrointestinal, were more common among children on cefixime than among those on ampicillin or amoxicillin. They were also more common among children on amoxicillin-clavulanate than among those on azithromycin.

CONCLUSIONS

The majority of uncomplicated cases of AOM resolve spontaneously without apparent suppurative complications. Ampicillin or amoxicillin confers a limited therapeutic benefit. There is no evidence to support any particular antibiotic regimens as more effective at relieving symptoms. Certain antibiotics are more likely than others to cause diarrhea and other adverse events.

Loracarbef versus clarithromycin in children with acute otitis media with effusion

Two multicenter, randomized, single-masked, parallel-group studies compared loracarbef and clarithromycin with regard to efficacy, tolerability, and patient acceptance. Three hundred thirty-four children aged 6 months to 3 years with acute otitis media with effusion received loracarbef (15 mg/kg) or clarithromycin (7.5 mg/kg) orally twice daily for 10 days. Patients were assessed for the presence of the diagnostic signs and symptoms of otitis media with effusion by physical examination and pneumatic otoscopy at 48 hours pretreatment, 3 to 5 days after initiation of treatment, 0 to 3 days after the final dose (posttreatment), and 14 to 21 days later (termination). Symptoms were assigned numeric values. Symptomatic response was assessed at the posttherapy and termination visits. Tolerability was determined by assessing adverse events, and a patient acceptance survey was completed by each patient's caregiver. The combined results of these 2 studies showed that the efficacy and tolerability of loracarbef were comparable to those of clarithromycin. Adverse events were reported by 46.4% of loracarbef patients and 41.0% of clarithromycin patients, with no statistically significant difference between groups. In the intent-to-treat analysis, 57.9% of loracarbef patients were cured at the termination of the study, compared with 55.7% of clarithromycin patients. Improvement was seen in 4.1% of loracarbef patients and 2.7% of clarithromycin patients. Results of the patient acceptance survey showed a clear preference for loracarbef over clarithromycin. Difficulties with administration of treatment were reported by 36.3% of clarithromycin caregivers, compared with 7.8% of loracarbef caregivers (P < 0.001). A desire to stop treatment was reported by 23.8% of clarithromycin caregivers, compared with 7.8% of loracarbef caregivers (P < 0.001). Taste and texture issues were most frequently cited as reasons for nonacceptance.

Comparison of cefprozil, cefpodoxime proxetil, loracarbef, cefixime, and ceftibuten

OBJECTIVE

To discuss the pharmacokinetics, spectrum of activity, clinical trials, and adverse effects of cefprozil, cefpodoxime proxetil, loracarbef, cefixime, and ceftibuten, an investigational cephalosporin.

DATA SOURCES

Literature was identified by a MEDLINE search from 1986 to January 1995.

STUDY SELECTION

Randomized, controlled studies were selected for evaluation; however, uncontrolled studies were included when data were limited for indications approved by the Food and Drug Administration.

DATA EXTRACTION

Data were evaluated with respect to in vitro activity, study design, clinical and microbiologic outcomes, and adverse drug reactions.

DATA SYNTHESIS

Cefprozil, cefpodoxime proxetil, loracarbef, cefixime, and cefributen are active in vitro against organisms frequently involved in community-acquired infections such as Streptococcus pneumoniae, Escherichia coli, beta-lactamase-positive or -negative Haemophilus influenzae, and Moraxella catarrhalis. Except for cefixime and ceflibuten, they all are active against methicillin-susceptible Staphylococcus aureus. Even though there were problems in study design (discussed within the text), clinical data demonstrate that these new oral beta-lactam compounds are as efficacious as conventional therapies for a variety of community-acquired infections.

CONCLUSIONS

Cefprozil, cefpodoxime, cefixime, loracarbef, and ceftibuten demonstrate in vitro activity against the major organisms that cause community-acquired infections. Clinical trials confirm that these agents are as effective as traditional therapies for the management of acute otitis media, pharyngitis/tonsillitis, sinusitis, bronchitis, pneumonia, urinary tract infections, and skin and skin-structure infections. In addition, cefixime and cefpodoxime are effective therapies for uncomplicated gonococcal infections. Selection of a specific agent will be influenced by susceptibility data and safety, as well as issues of compliance and cost.

Progression of tympanometry and acoustic reflectometry. Findings in children with acute otitis media

The presence of middle ear effusion (MEE) following acute otitis media (AOM) has been assessed by impedance tympanometry and acoustic reflectometry but has not been assessed serially from the time of presentation for AOM in the same group of patients. This descriptive study examined serial measurements by tympanometry and reflectometry in children with clinical AOM at the time of diagnosis, 3 to 5 days later, and at final follow-up 12 to 15 days after diagnosis. The study entry criteria were conservative in order to represent obvious cases of AOM and included 90 patients representing 107 ears. The objective was to describe the evolution of instrumental findings and to attempt to identify unique patient subpopulations with differing prognoses. We found that combined use of initial tympanometry and reflectometry, while yielding intriguing results, does not allow for identification of subpopulations with good or poor progression for MEE clearance at 2-week follow-up. It is our conclusion that initial tympanometry and reflectometry add to the cost of AOM diagnosis without clear benefit for the individual patient.

Comparative study of the safety and efficacy of clarithromycin and amoxicillin-clavulanate in the treatment of acute otitis media in children

The safety and efficacy of clarithromycin was compared with those of amoxicillin-potassium calvulanate for the treatment of acute otitis media in children. In a multicenter, randomized, investigator-blinded trial, 180 patients (6 months to 12 years of age) with acute otitis media were allocated to receive either clarithromycin, 15 mg/kg in two divided doses (n = 90), or amoxicillin-clavulanate, 40 mg/kg in three divided doses (n = 90), for 10 days. Middle ear samples were obtained by tympanocentesis from 175 of 180 patients. Pathogens were isolated from 137 samples (76%). Eighty-six patients in each treatment group were considered for efficacy analysis. Clinical cure or improvement was achieved within 4 days after treatment in 80 (93%) of 86 patients receiving clarithromycin and in 82 (95%) of 86 patients receiving amoxicillin-clavulanate. Recurrence of infection was observed between 5 and 35 days after treatment in 9 (11%) of 80 patients in the clarithromycin group and in 8 (10%) of 82 patients in the amoxicillin-clavulanate group. Middle ear effusion was found with similar frequency at the end of therapy and at follow-up visits in both treatment groups. Mild gastrointestinal signs and symptoms, the most common side effects, were noted in 20% and 52% of patients in the clarithromycin group and the amoxicillin-clavulanate group, respectively (p < 0.001). We conclude that clarithromycin is a safe and effective antimicrobial agent for the treatment of acute otitis media in children.

Loracarbef: a new orally administered carbacephem antibiotic

OBJECTIVE

To discuss the in vitro activity, pharmacokinetics, clinical efficacy, adverse effects, and relative merits of loracarbef, a new orally administered carbacephem antibiotic.

DATA SOURCES

Pertinent literature was identified by a review of selected journals and a MEDLINE search. Additional information was provided by the manufacturer of loracarbef.

STUDY SELECTION

All studies that have evaluated the clinical efficacy of loracarbef were included. In vitro studies were included if they used similar methodologies. Additional information was incorporated regarding the chemistry, pharmacokinetics, and adverse effects of loracarbef.

DATA SYNTHESIS

Loracarbef has antibacterial activity against most community-acquired respiratory tract, skin and skin structure, and urinary tract pathogens. The drug is well absorbed after oral administration and plasma concentrations achieved in patients are greater than the in vitro minimum inhibitory concentrations for most of the above bacteria. Although the majority of the clinical studies with loracarbef have methodologic deficiencies, loracarbef therapy has demonstrated similar efficacy in the treatment of upper respiratory tract (except otitis media), lower respiratory tract, skin and skin-structure, and urinary tract infections compared with accepted antibiotics. Potential advantages of the new carbacephem may be improved patient compliance with its less frequent dosing schedule (once or twice a day, depending on the infection), and a low incidence of adverse effects.

CONCLUSIONS

Preliminary data indicate that loracarbef may be an alternative agent for the treatment of a variety of community-acquired infections. Additional clinical experience and rigorously controlled comparative clinical trials are necessary to enable practitioners to fully define the therapeutic role of loracarbef.