By William Elliott, MD, FACP, and James Chan, PharmD, PhD

Dr. Elliott is Assistant Clinical Professor of Medicine, University of California, San Francisco.
Dr. Chan is Associate Clinical Professor, School of Pharmacy, University of California, San Francisco.

Drs. Elliott and Chan report no financial relationships relevant to this field of study.

The FDA has approved a new antimicrobial for the topical treatment of impetigo. Ozenoxacin is a nonfluorinated quinolone antimicrobial with bactericidal activity against Staphylococcus aureus and Streptococcus pyogenes, as well as activity against methicillin-resistant S. aureus.1,2 It is marketed as Xepi.

INDICATIONS

Ozenoxacin is indicated for the topical treatment of impetigo due to S. aureus and S. pyogenes in adult patients and pediatric patients ≥ 2 months of age.1

DOSAGE

Apply a thin layer topically to the affected area twice daily for five days.1 The affected area may be up to 100 cm2 or 2% of the total body surface area but not in excess of 100 cm2 in pediatric patients.1 The treated area may be covered with a sterile bandage or gauze dressing. Ozenoxacin is available as a 1% cream (10 g, 30 g, and 45 g tubes).

POTENTIAL ADVANTAGES

Ozenoxacin offers a new topical antimicrobial from a different pharmacologic class for impetigo.

POTENTIAL DISADVANTAGES

The drug is more effective than placebo; however, in the clinical trials, a significant percentage of subjects (44% and 63%) were considered clinical failures.1

COMMENTS

The approval of ozenoxacin was based on two Phase III studies.1,3 Subjects with impetigo affecting up to 100 cm2 and not exceeding 2% of body surface and ≤ 11 years of age were randomized to ozenoxacin or placebo. Both were applied twice daily for five days. Subjects with preexisting eczematous dermatitis or clinical evidence of secondary infections were excluded.

Overall clinical success was defined as no need for additional antimicrobial therapy on the baseline affected area and absence/reduction in clinical signs and symptoms at the end of therapy (days 6-7). This varied slightly between studies. Study 1 assessed the absence of exudate/pus, crusting, tissue warmth, and pain, as well as erythema/inflammation, tissue edema, and itching as less than mild. In Study 2, endpoints were absence of blistering, exudates/pus, crusting, and itching/pain, and mild or improved erythema/inflammation.

Clinical successes were 34.8% vs. 19.2% in Study 1 and 54.4% vs. 37.9% in Study 2. In the subjects with the most frequently identified bacteria (S. aureus and S. pyogenes), clinical successes were 38% vs. 16% and 40% vs. 10% in Study 1 and 57% vs. 33% and 79% vs. 40% in Study 2. There is negligible systemic absorption of ozenoxacin when up to 1 g was applied to up to 200 cm2 of surface area on intact or abrade skin.1

CLINICAL IMPLICATIONS

Impetigo is a common bacterial skin infection, particularly in children 2-5 years of age.4 The most common type is nonbullous (70%) caused by S. aureus or S. pyogenes. The less common (30%) bullous generally is caused by S. aureus. The Infectious Diseases Society of America recommends topical or oral therapy.5

Topical treatment includes either mupirocin or retapamulin twice daily for five days. Ozenoxacin may be another option and is at least as comparable to retapamulin.2 The cost for ozenoxacin was not available at this time.

REFERENCES

  1. Xepi Prescribing Information. Medimetriks Pharmaceutical, Inc., December 2017.
  2. López Y, Tato M, Espinal P, et al. In vitro activity of Ozenoxacin against quinolone-susceptible and quinolone-resistant gram-positive bacteria. Antimicrob Agents Chemother 2013;57:6389-6392.
  3. Gropper S, Albareda N, Chelius K, et al. Ozenoxacin 1% cream in the treatment of impetigo: A multicenter, randomized, placebo- and retapamulin-controlled clinical trial. Future Microbiol 2014;9:1013-1023.
  4. Hartman-Adams H, Banvard C, Juckett G. Impetigo: Diagnosis and treatment. Ann Fam Physician 2014;90:229-235.
  5. Stevens DL, Bisno AL, Chambers HF, et al. Practice guidelines for the diagnosis and management of skin and soft tissue infections: 2014 update by the Infectious Diseases Society of America. Clin Infect Dis 2014;59:e10-52.