The present study demonstrates that a 5 day treatment regimen with 0.5% levofloxacin ophthalmic solution significantly hastens both microbial and clinical cure in patients with bacterial conjunctivitis. At all study visits, microbial eradication was achieved by almost twice as many patients treated with 0.5% levofloxacin as those receiving placebo (p <0.001). Similarly, clinical cure rates were significantly higher with 0.5% levofloxacin than with placebo at both the final visit (p = 0.020) and at end point (p = 0.026). In addition, patients treated with 0.5% levofloxacin achieved significantly faster resolution of most of the ocular signs and symptoms of bacterial conjunctivitis compared to patients who received placebo.
Although there were significantly more women in the 0.5% levofloxacin treatment group than in the placebo group (63.3% v
43.9% in the per protocol population, respectively), it is unlikely that this difference had any bearing on the results of the study. To our knowledge, sex differences in the incidence of bacterial conjunctivitis have not been reported. However, bacterial conjunctivitis is more common in children than adults and often occurs in epidemics.1
In the present study, 28% of enrolled patients were children 2–11 years of age. The microbial eradication rates for this patient subgroup were more than threefold higher in levofloxacin treated patients (88%) than in placebo treated patients (24%, p <0.001). Notably, 0.5% levofloxacin was much more effective than placebo in eradicating S pneumoniae
and H influenzae
, two of the most common causative organisms in children.14
Clinical cure rates among children were 88% for those treated with 0.5% levofloxacin and 53% for those receiving placebo.
In the United States, children who demonstrate symptoms of conjunctivitis are frequently required to abstain from day care or school because of the concern of disease transmission to other children. The same concerns may apply to adults as well, resulting in lost days of economic productivity. Thus, a 5 day treatment course with levofloxacin 0.5%, which was demonstrated in this study to significantly improve the rates of clinical cure and hasten the eradication of infectious organisms compared to placebo, may have benefits from both a public health and an economic standpoint. Although the pharmacoeconomic implications associated with treatment of bacterial conjunctivitis were beyond the scope of this study, this issue may be an important area for future research.
Earlier studies of older topical fluoroquinolones, such as ciprofloxacin, in the treatment of patients with bacterial conjunctivitis and blepharitis demonstrated eradication or reduction of pathogenic bacteria following a 7 day treatment period.15,16
The efficacy of the 5 day treatment regimen with 0.5% levofloxacin in the present study may also have implications for patient compliance and the development of antibiotic resistance. Premature discontinuation of antibiotic therapy or failure to adhere to the required frequency of administration may increase the risk of treatment failure and lead to prolonged exposure of organisms to subinhibitory concentrations of antibiotic. Thus, the use of an efficacious drug like 0.5% levofloxacin that allows for a shorter, 5 day treatment regimen may improve patient compliance and possibly reduce the risk for creating conditions that might favour selection for antibiotic resistant organisms.
Although S pneumoniae
, S aureus,
and H influenzae
are the most common aetiological pathogens in bacterial conjunctivitis, the disease can be caused by many different organisms.1
Thus, selection of a topical antibiotic with activity against a broad array of potential pathogens would be desirable in designing an empirical antimicrobial regimen for presumed bacterial conjunctivitis.
In the present study, 0.5% levofloxacin ophthalmic solution was effective in eradicating a broad spectrum of both Gram negative and Gram positive organisms.
The 5 day treatment regimen with 0.5% levofloxacin ophthalmic solution was well tolerated and demonstrated a safety profile that was similar to placebo; no statistically significant differences were detected between treatment groups in the overall incidence of adverse events and other safety variables. However, a subset analysis of the paediatric population demonstrated some significant differences favouring the administration of levofloxacin 0.5% over placebo. For example, no children (0%) in the 0.5% levofloxacin treatment group experienced a worsening of ocular symptoms, compared with 43% of those who received placebo (p = 0.001).
In parallel with the current study, a second phase III study of 0.5% levofloxacin treatment of bacterial conjunctivitis treatment was recently conducted.17
This study utilised an antibiotic dosing regimen identical to that employed in the current study, but instead of incorporating a placebo comparison group, an active treatment comparison group (0.3% ofloxacin ophthalmic solution) was used. The results from this study showed that a 5 day treatment regimen with 0.5% levofloxacin achieved microbial eradication rates that were statistically superior to those attained with 0.3% ofloxacin.17
Despite the higher concentration of active drug in 0.5% levofloxacin compared with 0.3% ofloxacin, no differences between treatment groups were observed in the incidence of treatment related adverse events.17
In summary, the present study demonstrates that a 5 day treatment regimen with 0.5% levofloxacin ophthalmic solution is safe and effective for the treatment of bacterial conjunctivitis in both children and adults. Results from this study support the current consensus view that despite the self limited nature of bacterial conjunctivitis, treatment of presumed bacterial conjunctivitis with topical antibiotics may provide both individual and public health benefits. Compared to placebo, levofloxacin 0.5% demonstrated higher rates of clinical cure and lower rates of symptomatic relapse in children, and faster rates of microbiological cure in both adults and children. A 5 day course of levofloxacin 0.5% for bacterial conjunctivitis may therefore be beneficial in reducing symptomatology and decreasing the potential risk of disease transmission through person to person spread.