Interim Results of Trials of Chemotherapy Plus Electric Pulses

Genetronics Biomedical Ltd announced interim dataand results of phase II clinical trials evaluating the company’s electroporation therapy (EPT) system, which combines an intratumoral injection of a chemotherapeutic agent with a pulsed electric field, in squamous cell carcinoma of the head and neck. Data from the trials, which were conducted in the United States and Canada, were presented at the 35th annual meeting of the American Society of Clinical Oncology (ASCO). Genetronics also announced preliminary data and results from a similar study conducted in Europe.

Trial Protocols

A total of 33 patients with advanced head and neck cancer who had not responded to conventional therapy with radiation, chemotherapy, surgery, or a combination of these modalities were enrolled in two multicenter phase II trials conducted at 17 sites in the United States and Canada. One of the trials was a crossover, controlled study; the other was an open-label trial. Twelve additional patients were treated in a similar, open-label trial conducted in Europe.

In each case, the patients’ lesions were treated with bleomycin (Blenoxane) and the EPT system. This treatment increases the permeability of the cell membranes, resulting in significantly enhanced intracellular delivery of the drug (bleomycin). In this interim analysis, clinical response was determined either by complete disappearance of the tumor or by a reduction in its size (at least 50%).

Results of the Phase II American Studies

Table 1 summarizes the results of all five studies. The two phase II protocols involved a total of 42 tumors treated with bleomycin and EPT. Tumors treated in the trial included squamous cell carcinoma of the face, oral cavity, pharynx, larynx, and sinus. The volume of tumors treated ranged from < 1 mm³ to > 132 mm³.

In the crossover, controlled, phase II study, patients initially received only bleomycin (the control group). Patients who did not respond to the drug alone were then treated with the complete system of drug and electric field. Of the 33 lesions in 23 patients treated only with drug, none demonstrated a clinical response. Subsequently, 15 of these patients, having 18 lesions, were treated with bleomycin and EPT, and 61% achieved a clinical response.

 In the open-label phase II study, all patients received full EPT as their initial treatment. Among the 18 patients (24 lesions) so treated, 67% achieved a clinical response. Overall, therefore, the two studies showed a clinical response rate of 64%.

Results of the European Study

The European study enrolled 12 patients who had a total of 19 tumors. A 64% clinical response was measured (12 tumors). In the earlier phase I/Il trial with eight patients, conducted at Rush-Presbyterian-St. Luke’s Hospital in Chicago, six (75%) of the eight tumors treated with full EPT demonstrated a clinical response, with five of the responding tumors disappearing completely.

“These interim results suggest that electroporation with intralesional bleomycin treatment is a promising means for the treatment of squamous cell carcinoma of the head and neck,” said Paul Goldfarb,MD, medical director at Genetronics. “Our EPT treatment for head and neck cancer potentially offers several significant advantages compared to conventional therapies.”

Because these are interim results, the absolute values, including percentage of tumors achieving clinical responses, are likely to change upon more complete analysis of data from the clinical trials.

The clinical trial sites in the United States and Canada are: Abbott Northwestern Hospital, Minneapolis; University of Arkansas Medical Center, Little Rock; University of Oklahoma Health Sciences, Oklahoma City; H. Lee Moffit Cancer Center, Tampa; Louisiana State University Medical Center, Shreveport; Rush-Presbyterian-St. Luke’s Medical Center, Chicago; University of Tennessee, Memphis; University of Kansas Medical Center, Kansas City; University of California at San Diego; Colorado Head and Neck, Denver; Toronto Hospital, Ontario; Jewish General Hospital, Montreal; Manitoba Cancer Foundation, Winnipeg; Victoria General Hospital, Halifax; and University of Calgary, Alberta.