At the annual meeting of the American Society of Clinical Oncology (ASCO), Mayo investigators report that cancer in about two-thirds of 37 patients with aggressive differentiated thyroid cancer treated with the drug pazopanib either stopped growing, or quickly shrank.
The patient responses seen to date are promising, the researchers say, because all patients had fast-growing cancers that had spread to their lungs, with half involving lymph nodes and 39 percent also involving bones.
"The benefits were striking in many patients to a degree we have not previously seen in thyroid cancer in response to other therapies, including the standard treatment of radioiodine," says Keith Bible, M.D., Ph.D., a medical oncologist and researcher who led the multicenter clinical trial funded by the National Cancer Institute. Most of the patients treated were enrolled at the Mayo Clinic campuses in Minnesota and Florida.
Approximately one-third of patients achieved sustained and dramatic benefit from pazopanib, while another one-third experienced stabilization of their cancer or some tumor shrinkage. The remaining one-third of patients did not benefit from the drug. The agent was also well tolerated by the majority of patients, Dr. Bible adds.
What is not yet known, however, is the drug's effect on overall survival. "We need more time to establish that definitively," says Dr. Bible. "The trial has been going on for just over a year, and some of our patients are still maintaining a response, while others have not been in the study long enough for us to confirm duration of response." He notes that of the 37 original trial participants, two have died — one from cancer progression and another from other causes.
The National Cancer Institute estimated that 37,340 new cases of thyroid cancer would be diagnosed in 2008, with 1,590 deaths from the cancer. The cancer is much more common in women; it is the seventh most common cancer in women in the U.S. The occurrence of thyroid cancer has recently been rising.
Most thyroid cancers are of two major "differentiated" types — papillary thyroid cancer (the most common, accounting for 75 percent of cases) and follicular thyroid cancer (15 percent).
Fortunately, most patients with thyroid cancer respond well to surgery and to follow-up treatment with radioiodine; even if the cancer recurs and spreads, the disease progresses slowly in most patients, Dr. Bible says. "Many patients do well for a long time without the need of additional therapy," he says. However, about 5 percent of these patients experience rapidly progressing life-threatening disease that is insensitive to radioiodine and other treatment approaches. "Until only recently, we have not had any effective therapies for such patients."
Pazopanib is an experimental agent that is also being studied in advanced kidney, ovarian and other cancers. The drug, administered in pill form, targets proteins involved in angiogenesis, the growth of new blood vessels that has a critical role in the growth and spread of tumors. The proteins that pazopanib targets include vascular endothelial growth factor receptor (VEGFR), platelet-derived growth factor receptor (PDGFR), c-kit and Ret.
Mayo investigators are also leading clinical trials to test pazopanib in two other thyroid cancer subtypes -medullary, which does not respond to radioiodine, and anaplastic, the most aggressive subtype.
Dr. Bible says plans are also under way to test pazopanib in a larger, controlled and randomized clinical trial of patients with advanced differentiated thyroid cancer. Researchers want to more accurately assess benefits and risks.
About Mayo Clinic
Mayo Clinic is the first and largest integrated, not-for-profit group practice in the world. Doctors from every medical specialty work together to care for patients, joined by common systems and a philosophy of "the needs of the patient come first." More than 3,300 physicians, scientists and researchers and 46,000 allied health staff work at Mayo Clinic, which has sites in Rochester, Minn., Jacksonville, Fla., and Scottsdale/Phoenix, Ariz. Collectively, the three locations treat more than half a million people each year. To obtain the latest news releases from Mayo Clinic, go to www.mayoclinic.org/news. For information about research and education, visit www.mayo.edu. MayoClinic.com (www.mayoclinic.com) is available as a resource for your health stories.
VIDEO ALERT: Additional audio and video resources, including excerpts from an interview with Dr. Keith Bible describing the research, are available on the Mayo Clinic News Blog.
Karl Oestreich | EurekAlert!
Hot cars can hit deadly temperatures in as little as one hour
24.05.2018 | Arizona State University
3D images of cancer cells in the body: Medical physicists from Halle present new method
16.05.2018 | Martin-Luther-Universität Halle-Wittenberg
A research team led by physicists at the Technical University of Munich (TUM) has developed molecular nanoswitches that can be toggled between two structurally different states using an applied voltage. They can serve as the basis for a pioneering class of devices that could replace silicon-based components with organic molecules.
The development of new electronic technologies drives the incessant reduction of functional component sizes. In the context of an international collaborative...
At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.
At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...
There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?
At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...
So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics
Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...
The historic first detection of gravitational waves from colliding black holes far outside our galaxy opened a new window to understanding the universe. A...
02.05.2018 | Event News
13.04.2018 | Event News
12.04.2018 | Event News
24.05.2018 | Ecology, The Environment and Conservation
24.05.2018 | Medical Engineering
24.05.2018 | Physics and Astronomy