SIR-SpheresTM microspheres offer hope to patients diagnosed with inoperable liver cancer. It is a localized radiation treatment that is currently active in the liver and therefore delivers high doses of radiation directly to the tumour site while sparing healthy liver tissue.
The microspheres are extremely small resin beads measuring about one third the diameter of a strand of hair and labelled with yttrium-90, a beta radiation emitter. The beads are injected via a transcatheter procedure into the hepatic artery, which supplies the liver with blood, and are carried directly to the tumour site. The beads then emit radiation to destroy the cancerous cells before the radioactive material decays completely within about four weeks.
“Radiation is commonly used to kill cancer cells, but the more targeted the treatment, the lower the risk of side effects,” explains CEO Nigel Lange. “With external beam radiation, you can only deliver so much radiation without collateral damage to the healthy liver. The radiation also has to pass through other organs on its way to the tumour, thus increasing the potential for concurrent damage. SIR-SpheresTM microspheres have been developed to deliver treatment directly to the site of the tumour and are extremely localized in their effect. We can deliver up to 40 times as much radiation to a much more localized area compared with external radiation beam machines.”
The delivery device was developed by Bruce Gray in Australia in the 1990s, and like all medical breakthroughs, it underwent an exhaustive and lengthy process of trials and studies before gaining approval for use in humans.
Clinical studies are still ongoing, and it is currently being offered to patients whose tumours have not responded to chemotherapy sufficiently to allow surgery, which is a curative option. For patients with inoperable liver tumours, SIR-SpheresTM microspheres offer the opportunity to extend a patient’s life and enhance their quality of life.
“The next two years will be very important for us as the results of the ongoing clinical studies become clear,” says Mr. Lange. “Positive results will open up new doors for us globally and will also allow us to treat patients at an earlier stage of their disease and hopefully have a better impact on their lives. Positive results will also lead to improved patient access and greater reimbursement for our technology.”
The level-one evidence of overall survival and a listing in oncology practice guide lines are the key to achieving this. Although Sirtex is not in direct ontact with patients, many of the stories of the patients it is trying to help do feed back. A number of patient testimonials are featured on the company’s website.
“Our clients are mostly the academic medical centers in Europe, where they have multi-disciplinary tumour boards to decide how to treat each patient,” says Mr. Lange. “There is a high degree of involvement. Radiation therapy is a very exacting discipline, and not every patient is a suitable candidate.”
Although liver cancer is the focus of Sirtex’s work at present, it is also active in renal cancer with the first in-human trials currently underway. “We are looking at other organs, as well,” adds Mr. Lange. “All solid tumours are potential targets for our device, SIR-SpheresTM microspheres. If we can control the flow and deposition of the microspheres, then we can ensure that the radiation goes only where it is intended.”
The battle against cancer is an important one as the number of people living with a cancer diagnosis is projected to rise steeply in the future. “What we do is enormously important and, despite the challenges, immensely satisfying,” says Mr. Lange. “We have a highly committed team with virtually no employee turnover. We started with just three people and now have a team of 56 – all working to make a difference to patients’ lives.”
