Colon Cancer Treatment May Be More Toxic Than Thought
The next step is to figure out what this means and how to keep moving forward, says Saltz. "We have to bear in mind that [Camptosar] is still a very important drug and a good drug in the treatment of colon cancer," he tells WebMD.
Previous studies, he says, have shown Camptosar improves survival. "Now we have new information that we have to digest and analyze, in terms of these early deaths. We have to learn how to improve on what we have without abandoning it. ... Why did we see more deaths on these follow-up studies than in the first study? Nobody knows," Saltz says.
Indeed, the researchers aren't sure what is causing the high toxicity rate, but they note that 12 of the 14 patients who died in the North Central Cancer Treatment Group trial had several severe side effects in common, including dehydration resulting from diarrhea, nausea, and vomiting, an abnormally low number of a certain type of white blood cells, and blood infections. In the Cancer and Leukemia Group B trial, many of the deaths were related to blood clotting abnormalities.
"Exactly why they died, we are not certain," says O'Connell, adding that the researchers are sending out a team to gather patient information at every place that experienced an early patient death. "When we do have [some answers,] we will very likely submit another letter to The New England Journal of Medicine."
Ivan Horak, MD, vice president for clinical oncology, research, and development at Pharmacia Corp., makers of Camptosar, tells WebMD that the company is working closely with the NCI, the FDA, and the two cancer cooperative groups to gather and understand the data. Once they have analyzed the data, they will provide the doctors and the public with their findings.
In the meantime, Horak says that Pharmacia is getting the word out. "I want to be very clear that safety of the patient is the priority number one for all of us [at Pharmacia], and we will do everything humanly possible to really protect them," he says. Pharmacia voluntarily contacted cancer physicians last week about this issue. Also, a cancer newsletter published an in-depth article on the situation, and the data were presented and discussed at a lecture during an important cancer meeting recently.
Horak advises patients and their doctors to keep their eyes and ears open. "I think we spell out in enormous detail on [the drug's] label that patients on Camptosar should be watched very closely and very carefully," he says. "The first 60 days are usually the critical days; that is really where all the unexpected events -- at least according to the letter -- occurred. So patients should be followed very closely."
Likewise, doctors should be very familiar with the drug, and patients should know what to expect from it. "At this moment," Horak says, "this is probably the best recommendation we can give."