CHICAGO — Diabetic neuropathic foot ulcers treated with becaplermin were 30% more likely to heal during a 20-week study than ulcers not treated with the drug, David J. Margolis, M.D., said at the annual meeting of the Wound Healing Society.
The need for effective treatment is great, Dr. Margolis noted. Approximately 12% of diabetic patients develop foot ulcers; 80,000 amputations per year are attributed to diabetes.
In a retrospective cohort study of 25,098 patients, 10% were treated with becaplermin (Regranex), a topical recombinant human platelet-derived growth factor (rhPDGF).
The relative risk that the becaplermin-treated ulcers would heal after 20 weeks was 1.33 compared with standard care, and the relative risk of amputation was 0.86, similar to results from previous clinical trials, said Dr. Margolis, of the University of Pennsylvania. He and his colleagues estimated treatment effectiveness, rather than efficacy, by using propensity scores to control for selection bias.
Propensity studies involve additional probability and attempt to pin down which demographic factors contribute to results in a real-world setting. “We are trying to model why people received therapy,” Dr. Margolis said. The cases were drawn from a database of patients treated between 1998 and 2004 at a wound care center affiliated with Curative Health Services. “Some people had only 2 weeks of treatment, and others had 20 weeks,” Dr. Margolis noted. The mean length of treatment was 14 weeks.
Overall, 13% of the patients were treated with rhPDGF, and in general, these patients were more likely to be younger and male, and to have older wounds, than patients who were not treated with rhPDGF, he noted.
When asked how the Food and Drug Administration regards propensity studies, Dr. Margolis admitted that data of this type are not likely to prompt a change in drug labeling, for example. However, the FDA recognizes that the large sample size used in propensity score studies can provide useful information, he added.
The study was supported in part by funding from Ethicon Inc., which produces becaplermin (Regranex).