OncoSil™ is a single-use brachytherapy device comprising phosphorous-32 (32P) Microparticles suspended in a specially formulated Diluent. The OncoSil™ suspension, containing a pre-determined activity of radiation, is injected directly into the tumour to deliver an absorbed dose of 100 Gy in 81 days. The Microparticles remain in the tumour permanently.
OncoSil™ has received breakthrough device designation in the European Union, United Kingdom and the United States for the treatment of unresectable locally advanced pancreatic cancer in combination with chemotherapy.1,2
OncoSil™ is intended for intratumoural implantation into a pancreatic tumour via injection under endoscopic ultrasound guidance.
OncoSil™ is indicated for the treatment of patients with locally advanced unresectable pancreatic cancer, in combination with gemcitabine-based chemotherapy.
The OncoSil™ System is supplied sterile and is intended for single-patient, single-use.
OncoSil™ is currently approved for this indication in the European Union, the United Kingdom, Singapore, Malaysia and New Zealand.
The OncoSil™ System is for use within a licensed treatment facility. The OncoSil™ suspension is prepared by a radiopharmacist or by nuclear medicine personnel (ie an Authorised Dispenser). OncoSil™ implantation is performed by an endoscopist and a nuclear medicine physician or radiation oncologist (ie an Authorised User).
Both the Authorised User and Authorised Dispenser will have completed a training program provided by OncoSil Medical.
For OncoSil™ implantation, the tumour is accessed by ultrasound guided endoscopy. An overview of the preparation, delivery and implantation of OncoSil™ is provided below.
OncoSil™ Authorised Dispenser – radiopharmacist, nuclear medicine personnel.
The OncoSil™ System consists of OncoSil Microparticles and OncoSil Diluent. OncoSil Microparticles are suspended in the specially formulated Diluent for implantation. The dose is tailored for the tumour of each patient to receive 100 Gy of radiation from an activity calculated using the tumour volume. The volume implanted is equivalent to 8% of the tumour volume.
This dose is prepared within the Nuclear Medicine Department of the treatment facility or within a licensed radiopharmacy. Only appropriately licensed personnel, who have been trained in the preparation of OncoSil™ doses may prepare the product for implantation.
OncoSil™ is delivered by a suitably qualified endoscopist via ultrasound-guided endoscopy. An echoendoscope is guided into the upper intestine. An FNA needle is then loaded through the biopsy channel of the echoendoscope and slowly guided through the gastric wall or duodenal wall into the target pancreatic tumour.
OncoSil™ Authorised User – nuclear medicine physician, radiation oncologist.
Once the needle is positioned satisfactorily within the tumour, the syringe containing the prepared dose of OncoSil™ suspension is attached to the needle via a Luer tap. The required amount of OncoSil™ suspension is injected directly into the tumour by the Authorised User (i.e. an OncoSil Medical-trained nuclear medicine physician or radiation oncologist) by slowly depressing the plunger. Once the dose of OncoSil™ has been implanted into the tumour, the process of removing the needle assembly and scope takes place. Microparticle localisation is confirmed by SPECT-CT Bremsstrahlung imaging.
The radiation dose is equivalent to 100 Gy at implantation. With a phosphorous-32 half-life of ~2 weeks, 98% of the radiation is delivered within 81 days.† The Microparticles then remain in the tumour permanently.
†32P physical half-life: 14.27 days.
After the procedure, the patient is carefully monitored through observation and recording of vital signs, as clinically indicated.
Once the OncoSil™ device is implanted, the patient poses a very small radiation risk to staff and other contacts. Some general precautions should be observed, and local regulations may over-ride these general guidelines.
OncoSil™ implantation is an outpatient procedure although, depending on the patient’s condition and the clinician’s assessment, some patients may require admission overnight. Discharged patients are provided with information including safety practices that are to be followed post-implantation with OncoSil™.
In clinical studies, the following adverse events were considered to have a probable or definite causal relationship with OncoSil™:
Abdominal pain and discomfort
Abnormal liver function tests
If any signs of damage or ineffective sterile barrier integrity are observed for the OncoSil™ System, DO NOT USE the system and contact OncoSil Medical. Signs of damage and/or ineffective sterile barrier integrity may include, for example, broken vial, cracked vial, broken ring pull, non-intact tamper evident seals, missing vial caps etc.
OncoSil™ System is supplied sterile. There is no data to support the sterility or functionality of OncoSil™ past its expiration date.
OncoSil™ is contraindicated in patients who have a known history of hypersensitivity to silicon or phosphorous.
OncoSil™ is contraindicated where endoscopic ultrasound (EUS) directed implantation is considered hazardous (refer to Precautions).
Implantation of OncoSil™ should not occur in the following special situations:
Presence of multiple collateral vessels surrounding or adjacent to the target tumour
Presence (or significant risk) of varices near the target tumour
Caution is advised where previous EUS (eg diagnostic EUS-FNA) was considered technically too difficult.
Caution is strongly advised in the setting of recent, clinically significant pancreatitis. Implantation is not recommended.
Chemotherapy should not be administered within 48 hours either side of the OncoSil™ implantation.
OncoSil™ has not been studied in patients who have previously received radiotherapy to the target organ.
Since the combination of standard radiotherapy and OncoSil™ has not been investigated, additional radiotherapy is not recommended following OncoSil™ treatment.
Antibiotic prophylaxis to cover the OncoSil™ implantation procedure is advised. The selection and duration of antimicrobial regimen is based on local guidelines and practice.
Pain relief may be required to treat abdominal pain experienced immediately following implantation of OncoSil™.
Gastro-protection (eg with a proton-pump inhibitor or similar therapy), starting just prior to or at the time of implantation, and continued for up to 6 months post-implantation is considered reasonable.
The safety of OncoSil™ has not been established in patients who are pregnant or who, within twelve months of implantation, become pregnant.
The safety of OncoSil™ has not been established for future children of patients who are pregnant at the time of implantation or who, within twelve months of implantation, become pregnant.
The safety of OncoSil™ has not been established for children being breastfed by patients at the time of implantation or subsequent to implantation.
The safety of OncoSil™ has not been established in patients who are <18 years of age and is therefore not indicated for use in this population group.
Due to limited clinical experience, caution is advised when treating tumours with volumes in excess of 50cc with OncoSil™. A risk-benefit assessment by the implanting physician is strongly advised.
Radiation safety is an important consideration when using OncoSil™ System. From the receipt of the radioactive material, through preparation of the patient dose, implantation into the patient and release of the patient from the treatment facility there are many radiation safety practices that must be in place. These practices and procedures apply to the staff at the treatment facility, the patient and the patient’s family. The management of risks from ionising radiation requires actions based on the fundamental principles of radiation protection and safety and should be conducted in accordance with best practice in radiological protection.
OncoSil Medical provides a radiation safety guidance document as part of the treatment facility set-up procedure. This document covers many aspects of radiation safety management for implantation treatment facility personnel, patients and patients’ families. This document should be the first point of reference for all aspects of radiation safety associated with the use of OncoSil™ device. Patients are provided with a take-home brochure following their implantation procedure which contains guidance on radiation safety practices that should be adopted following their implantation.
OncoSil Medical radiation safety personnel are available to answer questions in relation to any material in the radiation safety guidance or the patient take-home brochure. Please contact your OncoSil Medical representative for more information on accessing these support services in your area.
REFERENCES: 1. US Food and Drug Administration (FDA) Breakthrough Device Designation. March 2020. 2. The British Standards Institute (BSI) designated the device as a breakthrough product under MEDDEV. April 2020. 3. OncoSil™ System instructions for use EMEA.
OncoSil™ in pancreatic cancer
OncoSil™ has been studied in two clinical trials in unresectable locally advanced pancreatic cancer