| |
Colorectal Cancer
|
|
| |
|
|
| |
|
|
|
|
|
my personal edition > colorectal cancer > news
E-Mail this DGDispatch to a colleague
DGDispatch
Molecular Advances Driving New Approaches in Colorectal Cancer Treatment: Presented at ONS
By Bonnie Darves
PHOENIX, AZ -- November 18, 2005 -- The past 3 years have seen dramatic changes in the treatment of both early-stage and advanced colorectal cancer (CRC), and more are on the horizon as molecular advances push novel agents, combination therapies, and increasing knowledge about the genetic markers that might influence a patient's response to treatment.
These rapidly occurring developments, in concert with promising trials now underway, are giving oncology nurses many more treatment options to discuss with their patients -- even those with metastatic disease, said Paula Muehlbauer, RN, MSN, OCN, clinical nurse specialist, National Institutes of Health (NIH), Bethesda, Maryland.
In her presentation here on November 12th at the Oncology Nursing Society 6th Annual Institutes of Learning (ONS), Ms. Muehlbauer pointed to the monoclonal antibodies cetuximab and bevacizumab, the oral prodrug capecitabine, the platin analog oxaliplatin, and the antineoplastic agent irinotecan as agents that are conferring significantly improved prognosis even for patients with advanced disease.
These new agents and highly targeted therapies, which are being tried in a variety of combinations, have doubled survival rates in some patients with advanced CRC, she said.
Cetuximab
One of the hottest developments involves cetuximab in metastatic CRC, as either a single agent for patients refractory to 5-fluorouracil (5-FU)/oxaliplatin or irinotecan-based therapies or in combination.
In one recent study, cetuximab achieved a 12% objective response rate in heavily pretreated patients who had exhausted their treatment options, Ms. Muehlbauer noted. Approved by the US Food and Drug Administration in 2004, cetuximab is also being tested in combination with irinotecan in patients who cannot tolerate irinotecan.
"What researchers are focusing on with cetuximab is the fact that we know it works better with other [chemotherapy] drugs than by itself, even though it can be given by itself as a second line for patients who can't take irinotecan," she said.
She added that several recent and ongoing studies are looking at possible combinations that may increase the effectiveness of either cetuximab or standard drugs.
In a recent trial for which preliminary data is now available, researchers are studying the potential benefit of a first-line metastatic CRC regimen that combines cetuximab with 5-fluorouracil (5-FU), folinic acid, and oxaliplatin.
On the genetics front, researchers are learning more about the factors that influence CRC progression and survival in patients with CRC. Those patients who have low level of expression of the epidermal growth factor receptor (EGFR), cyclooxygenase 2 (COX-2), and interleukin 8 (IL-8) tend to survive much longer than do patients with high expression -- 13.2 versus 2.3 months, Ms. Muehlbauer explained.
"We know this about other cancers as well, that overexpression of these genes is a poor prognostic variable," she noted.
Bevacizumab
The other promising approach in metastatic CRC involves bevacizumab. Approved in 2004, it is now being used in combination with intravenous 5-FU as a first-line therapy, and has quickly become one standard of care for metastatic disease. In the randomized phase 2 Bowel Oncology with Cetuximab Antibody (Bond 2) trial now underway at the NIH, researchers are looking at the safety and efficacy of a combined bevacizumab/cetuximab regimen in patients who are refractory to irinotecan.
At this stage, bevacizumab appears to boost the efficacy of cetuximab and cetuximab/irinotecan in irinotecan-refractory CRC patients who are bevacizumab-naïve, Ms. Muehlbauer said. She added that there is no evidence to date that toxicities increase because of synergistic factors. "They appear to be what we expect to see with the individual agents," she said.
Another combination experimental regimen being studied in metastatic CRC is the use of the agent PTK787 with 5-FU, leucovorin, and oxaliplatin (FOLFOX-4), which delivered a median survival of 16.6 months.
On another note, Ms. Muehlbauer said there may soon be a return to higher incidences of CRC, based on researchers' recent data on where the disease is showing up. "We're expecting a higher incidence of CRC in industrialized countries, primarily in immigrant communities," she said, a trend some are attributing to an increase in meat consumption and a decrease in exercise among certain ethnic groups.
The session was sponsored by the Targeted and Biological Therapies Special Interest Group.
[Presentation title: A Targeted Approach to Colorectal Cancer Management.]
All contents Copyright (c) 1995-2009 Doctor's Guide Publishing Limited. All rights reserved.
|
