The results of a combined analysis and separate analyses of four multicenter, randomized, parallel group studies that evaluated the effects of once-daily topical administration of becaplermin gel for the treatment of chronic, full thickness, lower extremity diabetic ulcers are presented. The four studies included a total of 922 patients with nonhealing lower extremity diabetic ulcers of at least 8 weeks' duration. Following initial complete sharp debridement of the ulcer, patients were randomized to receive a standardized regimen of good ulcer care alone, good ulcer care plus placebo gel, or good ulcer care plus becaplermin gel-30 microg/g, or good ulcer care plus becaplermin gel-100 microg/g, with various combinations of regimens used in the four studies. Safety was assessed by monitoring adverse events and by clinical laboratory evaluations. Meta-analytic statistical techniques were used in the combined analysis to establish homogeneity of treatment comparisons across studies. Based on an analysis of patients with baseline ulcer area common to all trials (</= 10 cm2), representing 95% of all patients, becaplermin gel-100 microg/g significantly increased (p = 0.007) the probability of complete healing compared with placebo gel. It was determined that for the median ulcer area of these patients, which was 1.5 cm2, the becaplermin gel-100 microg/g treatment group showed a 39% increase in complete healing compared with that of the placebo gel treatment group (50% vs. 36%, respectively, p = 0.007). Becaplermin gel-100 microg/g significantly decreased (p = 0.01) the time to complete healing compared with placebo gel, with the 35th percentile of time to complete healing being reduced by 30% (14.1 weeks vs. 20. 1 weeks, respectively). In patients with ulcers </= 5 cm2 at baseline (a more homogeneous group), becaplermin gel-100 microg/g also significantly increased the incidence of complete healing with a similar decrease in the time to healing. Adverse events reported during treatment or during a 3-month follow-up period were not unexpected for this patient population and were similar in nature and incidence across all treatment groups. We therefore conclude that treatment with becaplermin gel at a dose of 100 microg/g once daily, in conjunction with good ulcer care, is effective and well tolerated in patients with full thickness lower extremity diabetic ulcers.