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SAN DIEGO—The safety profile of delafloxacin, a novel fluoroquinolone, was comparable to vancomycin/aztreonam among study patients with acute bacterial skin and skin structure infections (ABSSSI), according to Sue K. Cammarata, MD, from Melinta Therapeutics, Lincolnshire, IL.

Dr. Cammarata and colleagues sought to compare the integrated safety outcomes between delafloxacin and vancomycin/aztreonam from two Phase 3 ABSSSI studies. The two global, multi-center, double-blind, randomized trial included adults with ABSSSI who were given oral or intravenous (IV) delafloxacin monotherapy every 12 hours or vancomycin 15mg/kg with aztreonam every 12 hours for 5 to 14 days. The pooled safety findings included all reported adverse events from baseline to 30 days post-final dose of the study drug; specific lab tests were also obtained from baseline through Days 21 to 28. 

A total of 1,492 patients (average age: 49 years) with ABSSSI received at least 1 dose of treatment. At baseline, nearly half (42%) of patients were obese, 11% had diabetes, and 16% had renal impairment. 

The researchers found that rates of any adverse event reported were similar between the two treatment groups: 45.1% for delafloxacin and 47.7% for vancomycin/aztreonam. 

“The most common adverse events [AEs] were gastrointestinal, seen in 17% and 13% of delafloxacin [DLX] and vancomycin/aztreonam [VAN/AZ] patients, respectively,” stated Dr. Cammarata. Fewer patients discontinued treatment due to related adverse events in the delafloxacin group vs. the vancomycin/aztreonam group (0.8% vs. 2.4%, respectively). There was a lower percentage of treatment-related adverse events (22.1% vs. 26.1%) and moderate to severe adverse events (18.3% vs. 20.2%) among patients treated with delafloxacin vs. vancomycin/aztreonam. 

During any point in the study, ALT >5XULN levels were seen in 1.1% and 1.7% of patients in the delafloxacin and vancomycin/aztreonam groups, respectively. Deaths were reported in 0.1% of the delafloxacin group and 0.4% of the vancomycin/aztreonam group but none were considered to be due to treatment. 

The incidence of fluoroquinolone-associated adverse events was not higher in the delafloxacin group vs. the vancomycin/aztreonam group, the authors noted. Moreover, there were no reports of tendon rupture or patients exhibiting symptoms consistent with fluoroquinolone-associated disability, the authors reported.

Based on the safety analysis, study authors were able to conclude that the safety profile of delafloxacin was comparable to vancomycin/aztreonam among patient with ABSSSI. The delafloxacin group exhibited “slightly lower incidence of treatment related AEs [TEAEs]” but the incidence of serious TEAEs were the same in both groups. 

Overall, the AE incidence between the treatment arms were similar “regardless of age, gender, renal impairment, diabetic status or hepatitis medical history.” 

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Cammarata, SK. Comparison of Safety Profile of Delafloxacin (DLX) versus Vancomycin/Aztreonam (VAN/AZ) in theTreatment of Patients (Pts) with Acute Bacterial Skin and Skin Structure Infections (ABSSSI): Integrated Safety Findings from Two Phase III Studies. Poster presented at IDWeek; October 4–8, 2017; San Diego, CA.