A randomized, blinded, multicenter trial of a gentamicin vancomycin gel (DFA-02) in patients undergoing abdominal surgery

BACKGROUND

SI is a significant medical problem. DFA-02 is an investigational bioresorbable modified release gel consisting of both gentamicin (16.8 mg/mL) and vancomycin (18.8 mg/mL). A Phase 2a study, where the drug was applied during surgical incision closure, suggested safety and tolerability but was not designed to assess its efficacy.

STUDY DESIGN

In a Phase 2b randomized, blinded trial patients undergoing abdominal, primarily colorectal, surgery were randomized (4:1:1) to one of three study arms: DFA-02, matching placebo gel, or standard of care (SOC) involving irrigation of the wound with normal saline. The DFA-02 and placebo gel groups received up to 20 mL of study drug inserted above the fascia during wound closure, and were treated in a double-blind manner; the SOC group was treated in a single-blind manner. The primary endpoint was SSI (adjudicated centrally by a blinded committee) through postoperative day 30.

RESULTS

Overall, 445 subjects (intention-to-treat) were randomized at 35 centers with 425 subjects completing the study and being evaluable. There were 67 SSIs (15.8%): 64.2% superficial, 7.5% deep, and 28.4% organ space. The incidence of SSI was not statistically significantly different between the DFA-02 and the placebo gel/SOC arms combined, 42/287 = 14.6% vs 25/138 = 18.1% (p = 0.36), respectively. Rehospitalization within 30 days was also similar between study groups (DFA-02 28.6%, placebo gel 21.4%, SOC 27.3%).

CONCLUSION

In this multicenter, blinded, randomized trial with central adjudication, the gentamicin/vancomycin gel was not associated with a significant reduction in SSI.

SUMMARY

Patients undergoing abdominal surgery were randomized to one of three study arms: DFA-02 gel consisting of both gentamicin and vancomycin, matching placebo gel, or standard of care (SOC). Of 425 patients completing the study at 35 sites the gentamicin/vancomycin gel was not associated with a significant reduction in SSI.

A randomized, double-blind, placebo controlled safety, tolerability, and pharmacokinetic dose escalation study of a gentamicin vancomycin gel in patients undergoing colorectal surgery

BACKGROUND

Despite numerous interventions promulgated by the Surgical Care Improve Project (SCIP) and other organizations, surgical site infection (SSI) continues to be a significant medical problem. DFA-02 is a novel bioresorbable modified-release gel consisting of both gentamicin (16.8 mg/mL) and vancomycin (18.8 mg/mL) to be applied during surgical incision closure for the prevention of SSIs. The following double-blind phase 2a trial was designed to test the safety and tolerability of DFA-02.

METHODS

At six US sites, the study planned to randomize 40 subjects undergoing colorectal surgery (30 with DFA-02, and eight with placebo gel) in four ascending dose cohorts (10-, 20-, 30-, and 40-mL study drug per wound). Safety was ascertained and serum pharmacokinetics (PK) was determined.

RESULTS

Study enrollment was discontinued after the first three dose cohorts (10, 20, and 30 mL) as even very large incisions could not accommodate more than 20 mL of gel, leaving no scientific justification for the 40-mL cohort. DFA-02 was well tolerated and showed no evidence of local tissue reaction or impairment of wound healing. No serious AEs were deemed related to study drug. Systemic exposure to gentamicin and vancomycin remained well below levels considered to be at higher risk for oto- or nephrotoxicity. The maximal gentamicin and vancomycin levels observed were 2.36 and 0.684 μg/mL at 6 h, which were well below the prespecified stopping criteria of 12 and 20 μg/mL, respectively.

CONCLUSIONS

In this small phase 2a study, the study drug was well tolerated and appeared to be free of serious adverse effects. Consistent with these findings, the PK values were consistent with gradual release of the antibiotics from the gel in the surgical site.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT01496352.