CHICAGO – Researchers reported notable advances in the war on cancer over the weekend, including treatments for lung, ovarian and skin cancers, but they cautioned that the disease continues to throw up daunting obstacles of cost and complexity.
New data presented at a major cancer conference provided both practice-changing information on the use of current treatments and powerful evidence of the potential for so-called targeted therapies, which attack cancer via genetic targets and other vulnerabilities.
The latest advances, however, typically involve expensive drugs that will require difficult choices by doctors, patients and insurers amid growing concern over health-care costs.
They also underscore the growing realization that cancer is not a single disease or even a single disease within each location in the body—say, breast, brain or lung. The more scientists know about genes, proteins and pathways that drive cancer, the more complex a disease it becomes.
"Cancer is like cable television," says George Sledge, a breast-cancer expert at Indiana University and newly elected president of the American Society of Clinical Oncology, which hosted the cancer meeting. "Thirty years ago you had three channels. Now you have 500."
The challenge for cancer researchers increasingly is to match the right drug with the right channel.
Sometimes that means going after a tumor directly, aided by genetic anomalies that make a tumor resistant to treatment in one patient but sensitive to it in another.
In one tantalizing example at the meeting, researchers said a drug being developed by Pfizer Inc., called crizotinib, caused tumors to shrink or stabilize in 90 percent of 82 lung-cancer patients specially recruited for the study because they had an alteration in a gene known as ALK.
Tumors shrank more than 30 percent in 57 percent of the patients. While there wasn't a control arm in the study, researchers said the participants had undergone several previous treatments. Normally just 10 percent of such patients not screened for this genetic anomaly would have been expected to register a response to the treatment.
Lung cancer is the most common cause of cancer death among men and women, but only a 4 percent of the 220,000 Americans diagnosed with the disease each year have the genetic anomaly—or roughly 10,000 patients.
That significantly reduces the size of the potential lung-cancer market for the study, but it is larger than many other cancers.
Pfizer has already begun a larger study of the drug focusing on those patients to determine whether the drug will help prolong survival.
In another study, Roche Holding AG's drug Avastin, which works by starving tumors of their blood supply, extended the time women with ovarian cancer survived without progression of their disease by four months, to 14 months, when continued for up to two years after a regimen that included Avastin and chemotherapy together.
Ovarian is a particularly deadly cancer for women. Roche said the results were among the first to show a benefit for long-term use of Avastin.
But Avastin in the U.S. costs up to $56,000 a year, and such findings are certain to raise the question whether the benefit is worth the price.
"We have to think about the cost of therapy in the same way we think about long-term side effects," said Jennifer Obel, an oncologist at North Shore University Health System in Illinois.
The latest findings underscore the growing realization that cancer is not a single disease or even a single disease within each location in the body—say, breast, brain or lung.
The more scientists know about genes, proteins and pathways that drive cancer, the more complex a disease it becomes.
Another advance came in a study of a drug called ipilimumab, being developed by Bristol-Myers Squibb Co., that works not by attacking the tumor but by activating the body's immune system to go after the cancer.
In a study of 676 patients with an advanced stage of the deadly skin cancer melanoma, patients taking the medicine lived an average of 10 months compared with 6.5 months for those taking a cancer vaccine called gp100.
The findings reflect growing interest in a variety of approaches to marshal the body's immune system in the fight against cancer.
Bristol-Myers expects to file for marketing approval with the Food and Drug Administration later this year and is studying the medicine in other cancers.
But such advances have been offset by setbacks described in research at the meeting and in other recent findings that illustrate cancer's complexity.
A study of Eli Lilly & Co'.s Erbitux is one example. Two years ago, researchers found that Erbitux improved survival in patients with colon cancer that had spread or metastasized, as long as they had a normal copy of a gene called KRAS.
The expectation was that the drug would also have a benefit earlier in the disease process, for patients with the same normal KRAS gene whose cancer hadn't yet spread.
But a 1,760-patient study found no survival advantage for patients given Erbitux plus chemotherapy, compared with those given chemotherapy alone. "Maybe early-stage colon cancer is a different disease than late-stage disease," Dr. Obel observed.
In another case, Pfizer's Sutent, a significant advance in the treatment of kidney cancer when it came out in 2006, failed in studies presented at the meeting to improve a measure of survival in breast cancer patients. The company continues to study the medicine in other tumors, including those in the lung and prostate.
The hope was that each of these targeted treatments, which block markers present in a variety of tumor types, would prove successful against more types of cancers.
Roche executives were pleased with newly demonstrated benefits of Avastin in ovarian cancer.
The drug is already approved in certain patients with breast, colorectal, kidney, brain and lung cancer. Nevertheless, in previous studies, Avastin didn't improve outcomes in early-stage colon cancer nor in prostate cancer.
The advances "bring hope, but they also remind us that we need to remain humble in this fight against cancer," said Pascal Soriot, chief operating officer of Roche Group's pharmaceutical business. "It's going to take time and a lot of money before we get a cure."
A decade ago, a drug called Gleevec from Novartis SA electrified the cancer world with its ability to all but cure a deadly form of leukemia thanks to its effect on an aberrant gene known as the Philadelphia chromosome.
It helped transform cancer research into a hunt for genes and other biomarkers that might direct drug development and guide doctors in selecting treatments for their patients.
At the meeting, study data showed that two second-generation drugs—Sprycel from Bristol-Myers Squibb and Tasigna, also from Novartis—outperformed Gleevec in certain measures of treating chronic myelogenous leukemia.
Assuming the drugs, now approved for patients who fail on Gleevec, gain approval for first-line treatment, physicians and patients will have alternatives to one of cancer's iconic drugs.
Gleevec "was such a revolutionary step," says Robert Mayer, vice president for academic affairs at Dana-Farber Cancer Institute, Boston. "It is encouraging that we can find ways to improve the product."
Meantime, the hunt for other strategies for matching drugs to targets continues in earnest.
Among them: Researchers are beginning to use the ability to unravel the genetic sequence of tumors to determine which pathways are active no matter where they're located in the body.
Then they plan to match the patients with already approved drugs, no matter what type of cancer they're on the market for.