The study evaluated bleomycin sulfate (BS) followed by electroporation (EP) treatment in patients with recurrent in-breast or chest-wall tumors. EP treatment following intralesional injection of BS has been studied in various cancers, and significantly increased destruction of cancer cells within the treatment field. The treatment has also been used as an intracellular delivery system for gene therapies and DNA vaccines.

Patients with histologically confirmed recurrent breast cancer following partial or complete mastectomy received BS intratumorally, 1 unit/cm³ tumor volume, followed by EP under general anesthesia. A CE-marked medical device (MedPulser^®) and a six-needle array applicator were used to electroporate each tumor. Safety evaluations and monitoring for local tumor recurrence were performed periodically up to 24 weeks.

Ten female patients with 11 tumors were enrolled. The mean age was 58.0 years (range 43.6–67.7). The mean tumor volume was 1.81 cm³(0.01–6.60), the mean BS dose was 1.80 U (range 0.50–5.08), and the mean number of EP applications was 11 (range 7–16). No treatment-related serious adverse event was observed. Nonserious adverse events were unremarkable during the 30-day follow-up period. At 24 weeks, the complete response rate was 75% (6/8) among patients with evaluations for treated lesions; two patients were inevaluable for tumor response.

Treatment with this drug-device combination was well tolerated in these patients, a majority of whom were free of local disease at 24 weeks. These results suggest a promising potential for BS/EP as a new treatment for controlling local disease in patients with recurrent breast cancer.