Cancer Research Highlights
Phase III Lung and Pancreatic Cancer Trials Stopped
Two phase III clinical trials were suspended last week after it was determined that they were unlikely to meet their primary endpoints.
The ATTRACT-1 trial was testing the drug ASA404 in patients with previously untreated, advanced non-small cell lung cancer (NSCLC). ASA404, also called vadimezan, is a new type of angiogenesis inhibitor known as a vascular disrupting agent. The trial was halted after a planned interim analysis showed “that continuation of the trial would be futile, as there is little or no prospect of demonstrating a survival benefit,” the drug’s manufacturer, Antisoma, explained in a statement.
Termination of the trial comes approximately 2 months after encouraging results from a phase II trial of ASA404 as a first-line treatment for advanced NSCLC were reported at a lung cancer conference in San Francisco. In the phase II trial, the combination of ASA404 and chemotherapy nearly doubled median survival times compared with chemotherapy alone.
Also last week, GenVec announced the suspension of its phase III PACT trial, testing the drug TNFerade in patients with locally advanced pancreatic cancer. The trial was stopped after an interim data analysis showed that the trial “would not meet the goal of demonstrating persuasive evidence of clinical effectiveness that could form the basis for regulatory approval in the population chosen for study,” the company explained in a press statement.
TNFerade is a modified virus that carries the DNA for a protein known as tumor-necrosis factor. The drug is injected directly into tumors. In 2005, the company reported promising results from a phase I/II study of the drug in patients with pancreatic cancer. Late last year, the FDA granted TNFerade “orphan drug” status, which is used to promote the development of drugs for relatively rare diseases or conditions for which there are limited treatment options.
Use of Health Care Services May Contribute to Colorectal Cancer Disparities
Black Americans have a higher incidence of colorectal cancer and higher mortality from the disease than white Americans. A new study using data from the ongoing Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial (PLCO) suggested that use of health care services may play a larger role than biology in this disparity. The results were published online April 6 in the Journal of the National Cancer Institute.
Researchers led by Dr. Adeyinka Laiyemo from NCI’s Division of Cancer Prevention studied 57,561 non-Hispanic white and 3,011 non-Hispanic black PLCO participants who underwent sigmoidoscopy during baseline screening. According to PLCO protocol, patients with a colorectal polyp or mass detected during sigmoidoscopy would be referred to their regular physicians for diagnostic colonoscopy.
Although comparable numbers of black (25.5 percent) and white (23.9 percent) participants had an abnormal finding on their baseline screening tests, black participants were less likely than white participants to undergo a follow-up diagnostic colonoscopy (62.6 percent versus 72.4 percent, respectively). When analyzed by education level (a surrogate indicator for socioeconomic status) the difference was only statistically significant among participants with a high school education or less.
The researchers did not find a statistically significant difference in risk of colorectal cancer in blacks and whites at baseline screening. Overall, the results suggested “that the biology of colorectal cancer may not be materially different by race, at least in the early stages of carcinogenesis, but instead that health-care utilization differences among the races may play a more important role in the observed disparities in colorectal cancer,” stated the authors.
The study was not designed to identify factors responsible for lower use of health care by black participants, which may include procedural costs and cultural barriers, the authors concluded.
Complementary and Alternative Medicine Commonly Used by Pediatric Patients
Many pediatric cancer patients use complementary and alternative medicine (CAM), according to a systematic review published online March 22 in Pediatrics. The research team led by Dr. Felicity Bishop of the University of Southampton in the United Kingdom reviewed 28 studies that surveyed a total of 3,526 children from 14 countries between 1975 and 2005. Twenty-three of the studies were performed between 2000 and 2005, and 10 were performed in the United States.
The researchers found that 2 to 48 percent of surveyed children used herbal remedies (measured in 13 of the studies), 3 to 47 percent used dietary and nutritional interventions (measured in 13 of the studies), and 2 to 19 percent used megavitamins (measured in 7 of the studies). Other CAM modalities used included faith healing, mind-body therapies, and massage therapies.
Those surveyed cited various reasons for the child’s CAM use, including to help cure or fight the child’s cancer and to provide symptom relief (both from the cancer itself and from side effects of standard treatment). CAM use did not appear to be associated with the gender, age, ethnicity, or family income of the pediatric patients, indicating wide use across demographic groups.
Because some commonly used herbs and supplements can negatively interact with standard cancer treatments, the authors cautioned that “pediatric oncologists need to be aware that their patients (and their patients’ parents) will be seeking and integrating other therapeutic approaches while undergoing conventional treatments.”
Breast Cancer Study Tests Effects of Zoledronic Acid
Women with breast cancer who received the bone-preserving drug zoledronic acid (Zometa) along with chemotherapy were slightly less likely to have tumor cells detected in their bone marrow several months later than women who received chemotherapy alone. The results, published online in Lancet Oncology on April 1, are from a randomized phase II clinical trial.
The goal of the study was to see whether zoledronic acid, a type of bisphosphonate, could reduce the presence of disseminated tumor cells—or DTCs—in the bone marrow when given along with chemotherapy prior to surgery. The trial, led by Dr. Rebecca Aft of the Washington University School of Medicine in St. Louis, included 109 women with newly diagnosed stage II or stage III breast cancer who were randomly assigned to receive the combination therapy or chemotherapy alone.
After 3 months, 17 of 56 women treated with zoledronic acid had DTCs in their bone marrow compared with 25 of 53 patients who received chemotherapy only. This difference was not statistically significant, the researchers noted. At 12 months, the number of patients with detectable DTCs was essentially the same in both groups.
The study, which was funded by Novartis Pharmaceuticals and Pfizer Inc., also found that giving women zoledronic acid at the start of chemotherapy prevented a loss of bone density, measured 1 year later. This is consistent with other studies of bisphosphonates in breast cancer, the researchers noted.
“Zoledronic acid administered with chemotherapy resulted in a decreased proportion of patients with DTCs detected in the bone marrow at the time of surgery,” the researchers concluded. Results from this study and others suggest that zoledronic acid has anti-metastatic properties within the bone marrow and systemically, they noted.