Personalized Therapies For Thyroid Cancer Patients Are Effective
In what researchers are calling a breakthrough, patients with thyroid cancer that is resistant to radioactive iodine therapy were found to respond well to sorafenib, a University of Pennsylvania School of Medicine researcher reported today at the annual meeting of the American Society of Clinical Oncology (ASCO). The phase II clinical trial data highlight an intensive effort at the Abramson Cancer Center to develop effective, personalized therapies for these patients, who have previously had few options for treatment.
“This is not a transition, this is a breakthrough for our patients,” says Marcia S. Brose, MD, PhD, assistant professor of hematology/oncology, who led the trial. “This is the first significant progress in 30 years, since doxorubicin was approved in 1974, which is toxic and produces responses in only five percent or patients.”
What is also unique to the program led by Brose is the intensive lab-based efforts underway to understand the molecular basis of the responses, so that future therapies can be tailored to each patient. “We have a full set of biospecimens on this group of patients, which together with the clinical data will allow us to answer many questions related to target therapy for these patients,” Brose says.
An interim analysis published recently in the Journal of Clinical Oncology reported on the first 30 patients enrolled in the trial and first showed that sorafenib is an effective agent at treating advanced disease. Twenty-three percent of those patients achieved an objective partial response to therapy, with another 54 percent achieving durable stabilization of their disease.
Updated results presented at ASCO reveal that the responses translate into a median overall survival of more than 140 weeks -- a three-fold improvement over doxorubicin. (Progression-free survival data for the entire study cohort and the differentiated thyroid cancer patients which make up a majority of the patients studied will be presented at the meeting). Brose will present compelling data showing that a major component of the sorafenib response is anti-angiogenic – inhibiting the growth of blood vessels needed to support tumor growth – consistent with the mechanism seen in other tumors. A total of 55 patients have enrolled in the trial so far, and Brose and her team continue to follow their progress and characterize their samples.
Based on these findings and data from Dr. Brose’s and other phase II trials, the National Comprehensive Cancer Network clinical guidelines now recommend use of sorafenib for patients with radioactive iodine-refractory thyroid cancer who are not able to enter clinical trials. About 10 percent of the 30,000 patients diagnosed with thyroid cancer each year ultimately progress to this advanced disease, with tumors appearing in the bones, lungs and other sites.
“What became clear is that there was an enormous unmet need out there,” Brose says. “I have had patients come from as far away as Hawaii, Uruguay and northern Ontario.”
Brose became interested in thyroid cancer when she realized that it shared some genetic changes with renal cancer and melanoma, malignancies in other Penn clinical trials she was involved in. “Once I started studying it, I realized that very few oncologists treated or understood the disease due to the lack of successful treatments. So once these patients failed radioactive-iodine, they really had no options,” she says. “No one wants to be sent home and told there is no treatment available.”
Brose hopes to launch additional clinical trials this year as part of her effort to have a trial for patients with every type and stage of thyroid cancer, including a phase II trial for patients whose cancers have progressed despite sorafenib treatment.
Genetic mutations and immunohistochemistry data uncovered in tumor tissue from each of the patients enrolled is helping guide new treatment approaches, allowing each patient to receive the most effective therapy for their cancer.
“If you have tissue from patients and know how they respond to treatment, you have the chance to predict where you should go next,” Brose says. “We are really setting the foundation for a new treatment paradigm for this disease –– a paradigm which didn’t exist three years ago.”