SEATTLE and LONDON—May 9, 2011—Calypso Medical Technologies, Inc., developer of GPS for the Body^® technology used for the precise tracking of cancerous tumors, today announced the results of two clinical studies demonstrating that real-time tumor tracking with the Calypso^® System during five-day stereotactic body radiotherapy (SBRT) for prostate cancer enabled clinicians to reduce treatment margins and minimize dosimetric impact of prostate motion. Data from one of the studies was presented today at the 30^th Anniversary Congress of the European Society for Therapeutic Radiology and Oncology (ESTRO) in London. Calypso is exhibiting during this conference at booth #330.

“Stereotactic body radiation therapy requires significantly fewer treatment sessions compared to conventional radiation therapy, making it an increasingly appealing option for a number of cancers, including prostate,” said Kenneth Russell, M.D., chief medical officer of Calypso Medical. “Results from these studies and others suggest that continuous tracking of the target during radiation delivery with Calypso’s real-time tracking technology can safeguard radiation delivery and spare surrounding healthy tissue.” 

Researchers in the study highlighted at ESTRO treated eight patients and used the Calypso System to track and manage motion of the prostate during radiation therapy. Patients received a dose of 10 Gy per treatment (a.k.a. fraction) for a total of 50 Gy. Study authors retrospectively analyzed the intrafraction prostate motion recorded by the Calypso System during treatment and demonstrated that it is feasible to decrease the margin (extra space added around the planned target volume) because they could adequately manage the intrafraction prostate motion with Calypso’s continuous targeting. The effect was sparing more of the anterior rectum’s exposure to radiation. Reducing the dose to the rectum may decrease toxicity or allow higher doses to be used to better fight the cancer.

“As stereotactic body radiotherapy involves higher radiation doses than conventional intensity-modulated radiation therapy, reducing treatment margins is an important step in limiting side effects,” said Ryan Foster, Ph.D., an investigator in the study and assistant professor of radiation oncology at the University of Texas Southwestern Medical Center in Dallas. “This study demonstrates that the dosimetric impact of intrafraction motion during prostate SBRT delivery is not clinically significant when a rectal balloon is combined with Calypso for assessment and monitoring of intrafraction motion. Real-time tumor tracking may be an important tool in reducing treatment margins during SBRT for prostate cancer.”

In another five-day prostate SBRT study using Calypso real-time tracking to guide radiation therapy, authors reported favorable quality-of-life and toxicity outcomes. The study results of this fifty-four patient Phase II trial were recently presented at the 52nd Annual Meeting of the American Society for Radiation Oncology (ASTRO) and published in the November 2010 edition of the International Journal of Radiation Oncology •Biology• Physics.

Study authors had also participated in an earlier multi-institutional study entitled, “Assessing the Impact of Margin Reduction (AIM),” with results published in Urology in 2010. The AIM study demonstrated that prostate tumor tracking utilizing the Calypso System during high-dose intensity-modulated radiotherapy (IMRT) allowed physicians to deliver a higher dose of radiation with smaller PTV margins while reducing bowel, urinary, and sexual treatment related side effects. The recent prostate SBRT studies show that decreasing treatment margins by utilizing the Calypso System may yield similar results for five-day, higher dose therapy.

The Calypso System uses GPS for the Body technology to safely guide radiation delivery during prostate cancer treatment. Beacon^® electromagnetic transponders, smaller than a grain of rice, are permanently placed in a patient’s prostate or prostatic bed. Each transponder emits a unique radio frequency signal to the Calypso System, which then determines the exact location and motion information about the tumor target. Because the tumor can be accurately tracked and monitored, precise targeted radiation can be delivered to the tumor while sparing surrounding healthy tissue and organs. This is critical because any movement by a patient, including internal movement of the tumor, may cause the radiation to miss its intended target and hit adjacent healthy tissue. Calypso’s real-time position information allows physicians to safely deliver the maximum cancer radiation treatments directly to the tumor. The Calypso System, cleared by the U.S. Food & Drug Administration (FDA) for use in radiation therapy for the prostate and post-operative prostatic bed, has been used to treat more than 10,000 people worldwide. A May 2010 study published in Urology reported that patients treated with the Calypso System experienced fewer prostate radiation side effects including rectal, urinary and sexual dysfunction than those undergoing conventional radiation therapy.

In addition to showcasing the Calypso System, the company is featuring their new Dynamic Edge^™ Gating product along with investigational information for use in pancreatic and lung cancers at their booth at ESTRO.

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ESTRO FINAL 05.09.11.pdf