Besifloxacin

Risk Summary

There are no available human data for the use of besifloxacin during pregnancy to inform any drug-associated risks; however, systemic exposure to besifloxacin from ocular administration is low.

Oral administration of besifloxacin to pregnant rats during organogenesis or during the prenatal and postnatal period did not produce adverse embryofetal or offspring effects at clinically relevant systemic exposures [see Data].

Data

Animal Data

In an embryofetal development study in rats, the administration of besifloxacin at oral doses up to 1,000 mg/kg/day during organogenesis was not associated with visceral or skeletal malformations in rat fetuses, although this dose was associated with maternal toxicity (reduced body weight gain and food consumption) and maternal mortality. Increased post-implantation loss, decreased fetal body weights, and decreased fetal ossification were also observed. At this dose, the mean C_max in the rat dams was approximately 20 mcg/mL, approximately 46,500 times the mean plasma concentrations measured in humans at the recommended human ophthalmic dose (RHOD). The No Observed Adverse Effect Level (NOAEL) for this embryofetal development study was 100 mg/kg/day (C_max, 5 mcg/mL, approximately 11,600 times the mean plasma concentrations measured in humans at the RHOD).

In a prenatal and postnatal development study in rats, the NOAELs for both fetal/neonate and maternal toxicity were 100 mg/kg/day. At 1,000 mg/kg/day, pups weighed significantly less than controls and had a reduced neonatal survival rate. Attainment of developmental landmarks and sexual maturation was delayed, although surviving pups from this dose group that were reared to maturity did not demonstrate deficits in behavior, including activity, learning and memory, and their reproductive capacity appeared normal.

Risk Summary

There are no data on the presence of besifloxacin in human milk, the effects on the breastfed infant, or the effects on milk production. However, systemic exposure to besifloxacin following topical ocular administration is low, and it is not known whether measurable levels of besifloxacin would be present in maternal milk following topical ocular administration.

The developmental and health benefits of breastfeeding should be considered, along with the mother’s clinical need for besifloxacin, and any potential adverse effects on the breastfed infant from besifloxacin.

Long-term studies in animals to determine the carcinogenic potential of besifloxacin have not been performed.

No in vitro mutagenic activity of besifloxacin was observed in an Ames test (up to 3.33 mcg/plate) on bacterial tester strains Salmonella typhimurium TA98, TA100, TA1535, TA1537 and Escherichia coli WP2uvrA. However, it was mutagenic in S. typhimurium strain TA102 and E. coli strain WP2 (pKM101). Positive responses in these strains have been observed with other quinolones and are likely related to topoisomerase inhibition.

Besifloxacin induced chromosomal aberrations in CHO cells in vitro and it was positive in an in vivo mouse micronucleus assay at oral doses ≥1,500 mg/kg. Besifloxacin did not induce unscheduled DNA synthesis in hepatocytes cultured from rats given the test compound up to 2,000 mg/kg by the oral route. In a fertility and early embryonic development study in rats, besifloxacin did not impair the fertility of male or female rats at oral doses of up to 500 mg/kg/day. This dose is approximately 26,500 times higher than the mean plasma concentration measured in humans at the recommended human ophthalmic dose.

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in clinical practice.

The data described below reflect exposure to besifloxacin in approximately 1,000 patients between 1 and 98 years old with clinical signs and symptoms of bacterial conjunctivitis.

The most frequently reported ocular adverse reaction was conjunctival redness, reported in approximately 2% of patients.

Other adverse reactions reported in patients receiving besifloxacin occurring in approximately 1-2% of patients included: blurred vision, eye pain, eye irritation, eye pruritus and headache.