Electronic brachytherapy promises to take radiotherapy out of the clinic

February 20, 2006

Traditional forms of radiation therapy have a formidable new competitor. A nonradioactive form of brachytherapy, cleared late last year by the FDA and being readied for preliminary roll out, dramatically reduces the length of treatment for early-stage beast cancer following lumpectomy and promises to bring radiation therapy to physician offices and imaging centers.

Traditional forms of radiation therapy have a formidable new competitor. A nonradioactive form of brachytherapy, cleared late last year by the FDA and being readied for preliminary roll out, dramatically reduces the length of treatment for early-stage beast cancer following lumpectomy and promises to bring radiation therapy to physician offices and imaging centers.

The Axxent Electronic Brachytherapy system, developed by Xoft of Fremont, CA, is built around an implantable x-ray tube. Smaller than a single tine on a dinner fork, this tube can fire x-rays charged with up to 50,000 volts, thus taking the place of iridium isotopes (Ir-192). The body's attenuation of the x-rays and a lead apron draped across the patient are all that's needed to protect staff, obviating the kind of heavily shielded rooms typically built into oncology centers.

Driving the acceptance of the device is its potential to bring radiation therapy out of the clinic to physician group practices.

"The majority of radiation oncologists have their offices in residential settings, where they might see patients in between treatments done at a hospital," Klein said. "With Axxent, they could treat them in their offices in a standard examination room."

Axxent might even be used in imaging centers, he said, reflecting a trend in radiology toward combining imaging and minimally invasive therapy.

Treatment sessions last about a half-hour, including the five minutes during which the beam is on. Sessions are spread over five days, twice a day, a welcome alternative to the seven-week regimen prescribed when implanting radioactive seeds.

"We will be taking brachytherapy to a new level," said Michael Klein, Xoft CEO and president.

Early clinical tests were conducted at the Center for Advanced Targeted Radiation Therapies at the Swedish Cancer Institute in Seattle and the Rush University Medical Center in Chicago. Eight to 10 more sites will join them by midyear. Each will also provide feedback that Xoft needs to refine the application and training procedures to support a nationwide product launch.

"The temptation is to try to roll out as many units as you can as quickly as you can. But we will roll them out at a measured pace, so that we can properly scale our infrastructure - our service, installation, applications personnel - to match the adoption profile that we want to have," Klein said.

Early adopters will also gather the clinical results that Xoft executives hope will persuade new buyers to invest in electronic brachytherapy, he said. A patient registry of the first 1300 cases will look specifically at patient outcomes. The registry will be sponsored by the American Society of Breast Surgeons and the American College of Radiation Oncology. Even before this registry is complete, Klein hopes to have a new reimbursement code in place for Axxent.

"Although it is brachytherapy, our technology is less expensive, and we believe a new code is warranted," Klein said. "A new code will also help as we develop new applications."

He cites as a model the changeover from conventional radiotherapy to intensity-modulated radiotherapy, which allowed highly precise 3D conformal therapy. This change in technology was accompanied by a new reimbursement code.

"We will ride a wave of new technology, so we would prefer a new code - but we won't exactly be disappointed if it doesn't happen," Klein said.

The current brachytherapy code allows $4500 for a disposable balloon and $7800 for 10 fractions of brachytherapy. If this code is applied, customers will reach breakeven for their investments very quickly.

The capital equipment part of Axxent runs about $150,000. Buyers will be offered a treatment planning system, a modified Brachyvision unit, from Varian Medical. Brachyvision costs another $85,000.

Low-cost disposables will provide a quick return on their investment, according to Klein. These run about $5000 per treatment. Conventional brachytherapy is reimbursed at more than double that amount.

Because this x-ray source can be turned on and off at will, and because the body naturally attenuates virtually all of the radiation, treatments can be delivered in any clinical setting, rather than the specialized environments of oncology clinics.

The technology could theoretically be placed in any of the 9000 breast imaging centers in the U.S., according to Klein, a possibility that has drawn Xoft into talks about strategic alliances with imaging and surgical vendors.

"If you listen to the vendors of mammography equipment talk about their vision, they are trying to parallel the needs of the imaging centers with therapy, as these centers move from imaging to an increased focus on biopsy and, ultimately, treatment," he said.

Xoft will insist, however, that treatments are planned and administered under the direction of a radiation oncologist.

"While we are not concerned with who actually pays the money to buy the equipment and where treatment occurs, we are firm about the need for the technology to stay within the realm of radiation oncology, from the perspective of who is doing the treatment," he said.

Axxent has the potential to make isotope-based brachytherapy for breast cancer - and perhaps other oncological applications - obsolete, Klein said. As a precedent, he points out the effect linear accelerators had on cobalt radiation therapy, once widely practiced in the U.S., and today all but nonexistent.

Axxent could go beyond even that, cutting into demand for linear accelerators. The operators of this equipment, however, are not likely to balk at the introduction of Axxent. Many sites will welcome the opportunity to transfer some of their backlog of patients to electronic brachytherapy, Klein said.

"If these centers could find a way to move 20% to 25% of their patients out of shielded rooms, they could take on that many more patients," he said.

Studies of patients indicate that many women considering lumpectomy opt out of breast-sparing surgery with radiation therapy due to time, distance, or difficulty accessing radiation therapy centers. Of the 2000 sites performing radiation therapy, only about 650 perform brachytherapy, and not all of these handle breast cancer, he said.

"The beauty of this technology is that women can go virtually anywhere to get it done," Klein said.

The company has raised $30 million in preparation for dramatically scaling up the business. Xoft began hiring a sales force in fall 2005, recruiting experienced staff for key positions. They will focus initially on treatments for early-stage breast cancer, but this could soon change. By midyear, the company expects to submit an FDA application to market Axxent for the treatment of endometrial cancer.

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