Research article

Chemotherapeutic treatment efficacy and sensitivity are increased by adjuvant alternating electric fields (TTFields)

Eilon D Kirson¹ , Rosa S Schneiderman¹ , Vladimír Dbalý² , František Tovaryš² , Josef Vymazal² , Aviran Itzhaki¹ , Daniel Mordechovich¹ , Zoya Gurvich¹ , Esther Shmueli¹ , Dorit Goldsher^3,4 , Yoram Wasserman¹ and Yoram Palti^1,4

¹NovoCure Ltd., MATAM Advanced Technology Centre, Haifa 31905, Israel

²Na Homolce Hospital, Roentgenova 2, Prague 5, 150 30, Czech Republic

³Rambam Medical Center, PO Box 9602, Haifa 31096, Israel

⁴B. Rappaport Faculty of Medicine, Technion – Israel Institute of Technology, Technion City, Haifa 32000, Israel

author email corresponding author email

BMC Medical Physics 2009, 9:1doi:10.1186/1756-6649-9-1

Published:	8 January 2009

Abstract

Background

The present study explores the efficacy and toxicity of combining a new, non-toxic, cancer treatment modality, termed Tumor Treating Fields (TTFields), with chemotherapeutic treatment in-vitro, in-vivo and in a pilot clinical trial.

Methods

Cell proliferation in culture was studied in human breast carcinoma (MDA-MB-231) and human glioma (U-118) cell lines, exposed to TTFields, paclitaxel, doxorubicin, cyclophosphamide and dacarbazine (DTIC) separately and in combinations. In addition, we studied the effects of combining chemotherapy with TTFields in an animal tumor model and in a pilot clinical trial in recurrent and newly diagnosed GBM patients.

Results

The efficacy of TTFields-chemotherapy combination in-vitro was found to be additive with a tendency towards synergism for all drugs and cell lines tested (combination index ≤ 1). The sensitivity to chemotherapeutic treatment was increased by 1–3 orders of magnitude by adjuvant TTFields therapy (dose reduction indexes 23 – 1316). Similar findings were seen in an animal tumor model. Finally, 20 GBM patients were treated with TTFields for a median duration of 1 year. No TTFields related systemic toxicity was observed in any of these patients, nor was an increase in Temozolomide toxicity seen in patients receiving combined treatment. In newly diagnosed GBM patients, combining TTFields with Temozolomide treatment led to a progression free survival of 155 weeks and overall survival of 39+ months.

Conclusion

These results indicate that combining chemotherapeutic cancer treatment with TTFields may increase chemotherapeutic efficacy and sensitivity without increasing treatment related toxicity.