Regimen that includes twice-daily dose of cancer-activated pill is easier for patients
A chemotherapy regimen that combines twice-daily doses of a tumor-activated pill, capecitabine, with an intravenous infusion of another drug, irinotecan, every three weeks, appears to be as effective as standard intravenous therapy in treating metastatic colorectal cancer. The treatment also produces fewer side effects and is more convenient for patients, a national Phase II clinical study concludes.
"This treatment is more patient-friendly than the standard chemotherapy regimen used in many U.S. hospitals. Patients receive the same benefit without the discomfort and inconvenience of lengthy IV infusions. Also, they do not need to be admitted to the hospital during treatment," says Yehuda Z. Patt, M.D., chief of gastrointestinal oncology at the University of Maryland Greenebaum Cancer Center, professor of medicine at the University of Maryland School of Medicine and the principal investigator. I believe that it will eventually replace the IV treatment."
The standard therapy for metastatic colorectal cancer, or cancer that has spread to other organs, is 5-FU/LV (or 5-fluorouracil, plus leucovorin), which is given intravenously. It is often combined with another chemotherapy drug, irinotecan or oxaliplatin.
The results of the national multi-center study, which evaluated the use of oral capecitabine (Xeloda), plus irinotecan (Camposar), as a first-line treatment for metastatic colorectal cancer, were presented at the 2004 Gastrointestinal Cancers Symposium, held January 22-24, 2004, in San Francisco. The meeting is sponsored by the American Society of Clinical Oncology, the American Gastroenterology Association, the Society of Surgical Oncology and the American Society for Therapeutic Radiation and Oncology.
Oncologists at the University of Maryland Greenebaum Cancer Center are already using this newer regimen for some colorectal cancer patients, Dr. Patt says.
Fifty-two patients, most of them with colorectal cancers that had spread to the liver, participated in the national clinical trial. The patients received twice-daily doses of capecitabine for 14 days, plus a 30- to 90-minute IV infusion of irinotecan on the first day of this three-week treatment cycle.
Forty-six percent of the patients responded with partial or complete shrinkage of their tumors, and another 25 percent showed no progression of their disease. Side effects were mild or moderate and included nausea and diarrhea. In some cases, the patients' tumors shrank sufficiently to be surgically removed.
"The goal is to eradicate the cancer, or at least decrease it to a degree that we can surgically remove it," Dr. Patt says. He notes that the response rate is comparable to the standard 48-hour infusion of 5-FU/LV through a central venous catheter using a portable pump, combined with irinotecan, every two weeks. The newer regimen is also less toxic than another combination therapy in which patients receive short infusions of 5-FU/LV and irinotecan every week, Dr. Patt says.
Capecitabine is absorbed by the body and converted into 5-FU by a series of reactions mediated by several enzymes, the last of which is more abundant in tumor cells, resulting in higher concentrations of 5-FU in the tumor cells. 5-FU inhibits the production of both DNA and protein by the cancer cells that are necessary for the cancer to grow. Irinotecan also interferes with the growth of cancer cells, and each of the drugs heightens the effectiveness of the other.
"Mimicking infusion with twice-daily oral administration, capecitabine can replace infused 5-FU in combination therapy," the researchers conclude. They say the combination of the capecitabine pill and irinotecan should be an effective, safe and more convenient first-line option.
The research was conducted at cancer centers throughout the country including the University of Texas M.D. Anderson Cancer Center in Houston, the Nevada Cancer Center in Las Vegas, the New Mexico Cancer Research and Treatment Center in Albuquerque and the Roswell Park Cancer Center in Buffalo. Dr. Patt oversaw the research at M.D. Anderson Cancer Center before joining the University of Maryland Greenebaum Cancer Center in late 2002.
Currently, Dr. Patt is conducting another Phase II clinical study at the Greenebaum Cancer Center to evaluate the effectiveness of using capecitabine (Xeloda) and oxaliplatin, another chemotherapy drug, to shrink tumors in the liver that have spread from the colon before the patients undergo surgery. Patients will also receive this treatment after surgery.
The University of Maryland Greenebaum Cancer has a multidisciplinary approach, with teams of surgeons, radiation oncologists, medical oncologists and other specialists working together to tailor the best treatment plans for the patients.
According to the American Cancer Society, colorectal cancer is the second-leading cause of cancer-related deaths in the United States. An estimated 147,000 Americans will be diagnosed with the disease this year, and more than 56,000 will die from it.