Efficacy of 1.5% levofloxacin otic solution in treating acute otitis externa: A post hoc analysis of ENT103-3001, a multicenter randomized double-blind parallel-group placebo-controlled phase III study in otitis media with persistent otorrhea

Objective: In this post hoc analysis, we aimed to evaluate the efficacy of 1.5% levofloxacin (LVFX) otic solution for the treatment of acute otitis externa (AOE) in patients with nonintact tympanic membrane (NTM) accompanied by chronic suppurative and acute otitis media.

Methods: Digital endoscopic images of the tympanic membrane and cavity were evaluated. In addition, the full analysis set from the original ENT103-3001 study was analyzed to determine the efficacy of the 1.5% LVFX otic solution in treating patients with otitis media with persistent otorrhea. AOE was diagnosed by a study-specific blinded independent review committee (BIRC) in the present study, which reviewed the presence of inflammatory findings, such as edema, erosion, and/or erythema (redness), in the external ear canal on the digital endoscopic images acquired at screening. The improvement in the inflammatory findings in each diseased ear was evaluated by examining the digital endoscopic images acquired at the end of treatment (EOT; including study discontinuation) and follow-up (F/U) visits. Data regarding residual purulent otorrhea at EOT and F/U visits were assessed by the BIRC of the ENT103-3001 study. Similarly, otological symptoms at EOT were recorded in the patients' diaries, and the bacterial eradication rates were used from the ENT103-3001 study. Improvement was defined as the resolution of the inflammatory findings and purulent otorrhea.

Results: Among the 201 patients with otitis media, 161 patients had AOE (LVFX group, 82; placebo group, 79). The difference (95% confidence interval) between the groups at EOT was 27.3% (12.7, 40.3), and the proportion of patients showing improvement in all inflammatory findings in the external ear canal in the LVFX group (47.6%, 39/82) was significantly higher than that in the placebo group (20.3%, 16/79; Fisher's exact test, p < 0.001). Similarly, the bacterial eradication rate in the LVFX group (94.3%, 66/70) was also significantly higher than that in the placebo group (10.3%, 7/68; Fisher's exact test, p < 0.001).

Conclusion: The use of 1.5% LVFX otic solution resulted in a significantly higher rate of improvement in inflammatory findings in the external ear canal and bacterial eradication rate, indicating its efficacy. Thus, 1.5% LVFX otic solution may be an effective treatment for chronic suppurative otitis media and acute otitis media, as well as AOE with NTM.