Safety of irreversible electroporation treatment for metastatic disease in humans Silk Mikhail; Wimmer, Thomas; Getrajdman, George; Durack, Jeremy; Sofocleous, Constantinos T.; Solomon, Stephen B. Interventional Radiology & Image Guided Therapies Memorial Sloan Kettering Cancer Center. New York, NY

Agenda Background on Ablation Devices Physics (RFA, MWA, IRE) Pre-Clinical Data Clinical Applications

300GHZ 3HZ Thermal ablation uses Electromagnetic Spectrum 300 MHz RFARFA MWA Thermal ablation uses the EM frequencies of 3 Hz and 300 GHz.

Irreversible Electroporation Electroporation –Electric pulses create tiny holes in the cell –Temporary as long as the energy is low 360 V/cm –Chemotherapy and Genetic therapy delivery “Irreversible” –Higher energy 680 V/cm 1 Create permanent holes in the cell Cell loses essential molecules and internal signals tell the cell to die

Electroporation Reversible electroporation is used to allow genes and drugs to enter cells ( V/cm) Direct current pulse leads to elevation of transmembrane potentials creating permanent cell membrane pores: ~1,500 V/cm Strong electric fields applied across a cell can cause: Irreversible permeabilization of the cell membrane: “IRE”

How IRE kills cells

Advantages of IRE IRE is non-thermal –Little to no scar tissue formation –Structural Protein Sparing Nerves and bile ducts in the area of ablation have the potential to heal after treatment –No heat sink effect Compared to thermal techniques where blood flow dissipates heat. Electric pulses are not effected by blow flow.

Patient Demographics Table 1. Patient Demographics VariableData Total number of patients included29 Age range:42y-81y Sex: Male16 Female13 Treated tumor lesions43 Table 2. Tumor characteristics VariableData Total Tumors43 Tumor Size2.3cm <1 cm cm cm12 >3 cm12 Tumor location Liver29 Soft Tissue12 Lung1 Tumor type (%) Metastatic Colorectal26 Metastatic Pancreatic6 Metastatic Endometrial3 Metastatic Prostatic3 Metastatic Leiomyosarcoma2 Metastatic Hemangiopericytoma1 Metastatic Ovarian1 Metastatic Thyroid1

Multiple IRE electrodes to treat larger lesions minimum: 2 parallel electrodes spaced cm

NO Heat Sink Effect

Case close to bile duct and major vein Pre-TxTxPost-Tx 3 mo. f/u MRI

No tumor for +778 days

Perivascular/periductal Liver Metastases Perivascular/periductal Liver Metastases 28 patients/ 65 tumors: 1 arrhythmia; 1 PV thrombosis (3%) 6 months: 92% Complete Ablation Kingham P et al: IRE for Perivascular Hepatic Malignant Tumors. J Am Coll Surg 2012; 215(3):

Applicators Animal Lung IRE Post IRE: GGO 1 week 3 weeks LUNG close to bronchus

Tumor near airway Pre-Tx Tx Post-Tx 3 mo. PET scan

IRE as an Ablation Tool: Potential Advantages Non-Thermal: -Application in Locations non eligible for Thermal Ablation -Limit recurrences near vessels by avoiding the “heat sink” effect Cellular Kill Mechanism Avoids Damage to: - Extracellular Matrix. This may result in fewer complications: Near Bile Ducts, Intestines, Ureters, Bronchi, Vital structures.

51 year old with rectal cancer recurrence near rectum

NO tumor for +565 days

Transmural Necrosis; No Perforation at 14 days IRE Rectal Wall

Applications: IRE Where Thermal ablation is NOT feasible Pancreas: Locally advanced adenocarcinoma 100% success at 90 days. Martin RC e al J Am Coll Surg 2012; 215(3): Perivascular Liver Tumors. Kingham P et al: IRE for Perivascular Hepatic Malignant Tumors. J Am Coll Surg 2012; 215(3): Prostate: A potential Therapeutic Paradigm Shift. Ward JF Curr Opin Urol 2012; (2): Intracranial: Canine brain Surgery. Garcia PA Conf Proc IEEE Eng Med Biol Soc 2009: and Technol Cancer Res Treat 2011; 10(1): Blood Brain barrier Disruption: Rat Hjoui M et al. MRI study on reversible and irreversible electroporation induced blood brain barrier disruption. Plos One. 2012;7(8) Small Intenstine: Rat: Complete ablation but recovery of Epithelium in 3 weeks. Phillips MA. Br J Cancer 2012; 31; 106(3): 490-5

Enhancing Irreversible Electroporation A zone of Reversible electroporation Surrounds the Area of IRE A lethal agent can be targeted to the reversible zone: Electrochemotherapy Gene Electrotransfer Electrochemotherapy : A new technological approach in treatment of Liver Metastases. Edhemovic et al Technol Cancer Res Treat 2011 Oct; 10(5): Treatment Planning of Electroporation-Based medical Interventions: electrochemotherapy, gene electrotransfer and IRE Phys Med Biol 2012; 7;57(17) Model assumes 360 V/cm threshold for reversible and 680 V/cm threshold for irreversible Reversible Irreversible

Conclusion Unlike Thermal Ablation, IRE, can be performed in close proximity to bile ducts, major vessels, bladder, rectum, and nerves, with an acceptable safety profile. Longer term follow up is performed to determine efficacy. Further research will determine the potential of this new ablation technology