New technologies for prostate cancer therapy make debut

By Larry Haimovitch

Medical Device Daily Contributing Writer

May 22, 2008

AUA annual meeting

ORLANDO — The frenetic pace of technological innovation in the field of medical devices is well-known by all stakeholders in this industry. That was certainly apparent at this year's gathering of the American Urological Association (AUA; Linthicum, Maryland) the largest worldwide meeting for this specialty, which concluded here this week.

As in past years' AUA sessions, significant attention at this meeting was devoted to the myriad diagnostic and treatment modalities for prostate cancer, by far the most common cancer in men. According to the American Cancer Society (Atlanta), about 186,000 new cases of prostate cancer will be diagnosed in the U.S. this year.

About one in six American men will receive a diagnosis of prostate cancer during his lifetime, usually after age 60. This cancer will cause an estimated 29,000 deaths this year in the U.S., making it the second-leading cause of cancer death in men, exceeded only by lung cancer.

Since this cancer generally progresses quite slowly, about 15% of men newly diagnosed opt for "watchful waiting." However, for those that decide to seek an intervention, there are a plethora of choices currently available, with more on the horizon.

Various forms of radiation, such as external beam radiation therapy (EBRT), intensity modulated radiation therapy (IMRT) and brachytherapy and the long-time and conservative "gold standard" — surgical excision of the prostate (radical prostatectomy, or RP) — have long formed the backbone for treatment. Radiation and RP each accounts for around 40% of the prostate cancer treatment market, with cryoablation accounting for another 5% or so.

However, newer technologies have in recent years begun to heavily impact the traditional modalities. For example, robotically-assisted RP, marketed aggressively and astutely by Intuitive Surgical (Sunnyvale, California) now accounts for at least half of the overall RP procedure market. In 2007, an estimated 45,000 to 50,000 robotic RP procedures were performed, surpassing the number of conventional RP surgeries for the first time.

Intuitive's booth at the AUA was consistently packed with urologists eager to learn more about the technology and how to incorporate it into their surgical practice.

Two new and intriguing technologies were displayed by their corporate sponsors for the first time at an AUA meeting. Accuray (also Sunnyvale), which several years ago pioneered the concept of highly-precise robotic radiosurgery for brain tumors and then broadened into other types of cancers, has in the past couple of years begun to market its technology for prostate cancer.

The company's CyberKnife, which has been installed in more than 130 sites worldwide, integrates modern imaging technology, intelligent robotics and high-dose radiation delivery, merged with complex algorithms to precisely target cancerous tumors.

The CyberKnife appears to well-suited to prostate cancer. Its advanced robotics allow it to track, detect and correct for unpredictable prostate movement during therapy, thus accurately destroying the cancer while surrounding nerves and healthy tissue are safely preserved.

Because of its sub-millimeter accuracy, CyberKnife radiation doses can be far higher than conventional radiation, with the upshot that it can accomplish tumor destruction in just five sessions vs. 40 sessions for EBRT or IMRT to.

Compared to its longstanding successes in other cancers, its impact on the prostate cancer market is still modest. In the company's fiscal 2007, ended last June 30, about 600 prostate cancers were treated with CyberKnife. Although Accuray has not disclosed its prostate cancer cases so far this fiscal year, this number could easily triple or quadruple. Conversely, in the last fiscal year, roughly 8,000 brain cancers were treated, with an additional 2,000 cases each for lung and spine cancer.

Clearly, in the technology-crowded prostate cancer treatment market, more clinical data will be required to validate the technology. Thus it is not surprising that the company is in the early stages of two key clinical trials.

The first trial will be treating early stage organ confined cancers and will compare the CyberKnife to HDR (high dose rate) temporary brachytherapy. It will treat a total of 330 patients, who will then be followed for five years. The principal investigator is Don Fuller, MD, a radiation oncologist who founded the CyberKnife Centers of San Diego (San Diego) and is a strong proponent of the technology.

A second trial will enroll an additional 330 patients and also do a five-year follow-up. The principal investigator is Robert Meier, MD, a radiation oncologist from the Swedish Cancer Institute (Seattle). He also has had considerable experience with the CyberKnife in treating prostate cancer. This trial will compare CyberKnife to a homogeneous dose distribution in early-stage organ confined cancers.

At an even earlier stage of development is irreversible electroporation (IRE) technology that is being developed by the interventional radiology company AngioDynamics (Queensbury, New York). It provided some IRE information at its booth.

IRE energy is delivered through needles and image guidance very similar to existing ablative technologies (such as radio frequency or cryothermia) but instead of heating or freezing to kill the targeted tissue, it uses electrical fields to cause cell death. The powerful electrical field, which passes through an electrode array, causes permanent nanoscale defects or pores in the cell membranes. The permanently impaired cells are then removed through the body's natural immune system.

As compared to other ablation methods, it is highly selective and does not damage adjacent critical structures such as ducts and blood vessels

The technology was developed at the University of California, Berkeley and then licensed to a private company called Oncobionic. In October 2006, AngioDynamics signed an agreement to acquire Oncobionic, making an initial investment of $5 million and a commitment to pay an additional $20 million within two years, subject to successful human use of IRE.

Last month, AngioDynamics reported that the first human clinical cases, treating prostate cancer, had been performed and that it was moving forward with its plans to complete the acquisition of Oncobionic. As per the agreement, an additional $10 million was paid, with two more payments of $5 million each scheduled within the next 18 months (Medical Device Daily, April 25, 2008).

IRE has broad application within the field of cancer, but given the large number of cases occurring per year, the company has opted to begin with this area. Although six human cases have been performed to date, taking advantage of a 510(k) approval received in November 2006 for soft tissue ablation, AngioDynamics now will proceed with a prostate-specific clinical trial, first treating animals and then moving into human trials.

Although a full-scale market launch may be a few years away, this technology, in the words of Gary Onik, MD, the president of Oncobionic, shows " ... promise to become the next generation of ablation technology."

2009 American Urological Association Annual Meeting

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