Newsweek - National News, World News, Health, Technology, Entertainment and more... | Newsweek.com
SPONSORED BY
Full Post
Posted Monday, September 08, 2008 2:21 PM

Cancer: A Long List of Missed Opportunities

Sharon Begley

Mea culpa: Lab Notes was missing in action last week because I couldn’t tear myself away from interviewing oncologists for the story in this week’s magazine [] about the war on cancer. I wanted to chart the progress that has been made against the disease in the 37 years since Richard Nixon launched the war on cancer, and that meant talking to researchers and clinicians who have been in trenches for several decades. 

Their stories were heartbreaking, not only for the patients they lose but for the missed opportunities.

 

Advertisement

Gerold Bepler, chief of the division of thoracic oncology (that’s lung cancer) at H. Lee Moffitt Cancer Center, started his Ph.D. thesis on Hodgkin’s lymphoma in 1980 and then turned to lung cancer as a post-doctoral fellow. He recalled that the big breakthroughs in lung-cancer chemotherapy 25 years ago let patients with small-cell lung cancer survive a year instead of six-to-eight weeks, as had been the case before cisplatinin and other drugs were developed. “With non-small-cell lung cancer,” he recalls, “the response rate was much lower, maybe 15 to 20 percent, and it had remarkable toxicity. You wondered, were you really helping people if you made them so sick for the little extra time that you kept them alive?”

 

“The next breakthroughs were anti-nausea drugs in the mid-1980s to early 1990s. Cisplatinin became much easier to give. I remember people throwing up for a week at a time, before these drugs, when they got chemo once every three weeks. Suddenly, with the anti-nausea drugs, chemo became tolerable,” Bepler told me.

 

And what counts as progress against lung cancer? In the 1990s, 14 to 15 percent of patients lived at least five years. Today, Bepler said, 16 to 17 percent do. “It’s a very small number, and we are far, far, far from being able to cure this disease.”

Why is it so tough to treat? “Lung cells have developed mechanisms to cope with genotoxic stress,” Bepler told me. That means that the chemo drugs that act by damaging DNA, so that malignant cells cannot replicate, eventually stop working: the cancer cells turn on DNA-repair mechanisms or other pathways that render the chemo agents useless.

 

Like so many of the scientists I interviewed, Bepler points to many missed opportunities over the 37 years of the war on cancer. In his case, he proposed a study in the mid-1990s in which researchers would have taken samples of lung cancers, analyzed and stored them, and then determined which molecular profiles predicted response to which existing or future chemo drugs. “I struggled to get NCI [National Cancer Institute] approval,” Bepler said. “What gets funded depends on what people think at the time is hot, or in. I’ve served on NCI study sections [those are the panels of, usually, outside scientists who review grant proposals and score them, determining which get funded] so I can see it from both perspectives. When you start reading the applications, you are automatically drawn to the ones perceived to be interesting,” sometimes losing sight of the fact that the goal here is to treat cancer and not (only) discover cool things about the molecular biology of cancer. “In my case, people thought the idea couldn’t be implemented in patients because they didn’t think patients would be willing to have repeated biopsies,” which is what would have been required to match their tumor to a particular chemo drugs.

 

Yet that is what the current era of personalized cancer therapy is about. Bepler isn’t the only researcher who wanted to go down that path more than a decade ago. If he and others had been funded, who knows how much further we would be in the fight against lung cancer?
You must be a registered user to comment.  Click here to register.  Already a user?  Click here to login.

Member Comments

Posted By: Gregory D. Pawelski (October 26, 2008 at 10:16 PM)

Personalized Cancer Medicine Is Here, NOW!

As we enter the era of "personalized" medicine, it is time to take a fresh look at how we evaluate treatments for cancer patients. More emphasis is needed matching treatment to the patient. Patients would certainly have a better chance of success had their cancer been chemo-sensitive rather than chemo-resistant, where it is more apparent that chemotherapy improves the survival of patients, and where identifying the most effective chemotherapy would be more likely to improve survival.

Findings presented at the 41st Annual Meeting of the European Society for Clinical Investigation in Uppsala, Sweden and the Annual Meeting of the American Assoication for Cancer Research (AACR) in San Diego, CA concluded that "functional profiling" with cell-based assays is relevant for the study of both "conventional" and "targeted" anti-neoplastic drug agents (anti-tumor and anti-angiogenic activity) in primary cultures of "fresh" human tumors.

Cell-based Assays with "cell-death" endpoints can show disease-specific drug activity, are useful clinical and research tools for "conventional" and "targeted" drugs, and provide unique information complementary to that provided by "molecular" tests. There have been more than 25 peer-reviewed publications showing significant correlations between cell-death assay results and patient response and survival.

Many patients are treated not only with a "targeted" therapy drug like Tarceva, Avastin, or Iressa, but with a combination of chemotherapy drugs. Therefore, existing DNA or RNA sequences or expression of individual proteins often examine only one compenent of a much larger, interactive process. The oncologist might need to administer several chemotherapy drugs at varying doses because tumor cells express survival factors with a wide degree of individual cell variability.

There is a tactic of using biopsied cells to predict which cancer treatments will work best for the patient, by taking pieces of live "fresh" tumor tissue, applying different chemotherapy treatments to it, and examining the results to see which drug or combination of drugs does the best job killing the tumor cells. A cell-based assay test with "functional profiling," using a cell-death endpoint, can help see what treatments will not have the best opportunity of being successful (resistant) and identify drugs that have the best opportunity of being successful (sensitive).

Funtional profiling measures the response of the tumor cells to drug exposure. Following this exposure, they measure both cell metabolism and cell morphology. The integrated effect of the drugs on the whole cell, resulting in a cellular response to the drug, measuring the interaction of the entire genome. No matter which genes are being affected, functional profiling is measuring them through the surrogate of measuring if the cell is alive or dead.

For example, the epidermal growth factor receptor (EGFR) is a protein on the surface of a cell. EGFR-inhibiting drugs certainly do target specific genes, but even knowing what genes the drugs target doesn't tell you the whole story. Both Iressa and Tarceva target EGFR protein-tyrosine kinases. But all the EGFR mutation or amplificaton studies can tell us is whether or not the cells are potentially susceptible to this mechanism of attack. They don't tell you if Iressa is better or worse than Tarceva or other drugs which may target this. There are differences. The drugs have to get inside the cells in order to target anything. So, in different tumors, either Iressa or Tarceva might get in better or worse than the other. And the drugs may also be inactivated at different rates, also contributing to sensitivity versus resistance.

As an example of this testing, researchers have tested how well a pancreatic cancer patient can be treated successfully with a combination of drugs commonly used to fight lung, pancreatic, breast, and colorectal cancers. The pre-test can report prospectively to a physician specifically which chemotherapy agent would benefit a cancer patient. Drug sensitivity profiles differ significantly among cancer patients even when diagnosed with the same cancer.

The funtional profiling technique makes the statistically significant association between prospectively reported test results and patient survival. It can correlate test results that are obtained in the lab and reported to physicians prior to patient treatment, with significantly longer or shorter overall patient survival depending upon whether the drug was found to be effective or ineffective at killing the patient's tumor cells in the laboratory.

This could help solve the problem of knowing which patients can tolerate costly new treatments and their harmful side effects. These "smart" drugs are a really exciting element of cancer medicine, but do not work for everyone, and a pre-test to determine the efficacy of these drugs in a patient could be the first crucial step in personalizing treatment to the individual.

Literature Citation:

Functional profiling with cell culture-based assays for kinase and anti-angiogenic agents Eur J Clin Invest 37 (suppl. 1):60, 2007

Functional Profiling of Human Tumors in Primary Culture: A Platform for Drug Discovery and Therapy Selection (AACR: Apr 2008-AB-1546)


Posted By: Pat from Hendersonville (September 9, 2008 at 10:53 PM)

I've spent 35 years of my career in cancer care, beginning at St. Jude Children's Research Hospital in the early days of clinical research into childhood cancers.  The successful treatment of childhood cancers should be a model for future efforts in adults.  The reason that we've not been successful in adult cancers is two-fold.  The first is that less than 5 percent of adults are on clinical trials; the second is that clinical trials have been trial and error rather than targeted.  A greater emphasis on basic science research so that de novo trials can be developed rather than just adding new drugs to existing drug regimens is critical.  


Posted By: Pat from Hendersonville (September 9, 2008 at 10:52 PM)

I've spent 35 years of my career in cancer care, beginning at St. Jude Children's Research Hospital in the early days of clinical research into childhood cancers.  The successful treatment of childhood cancers should be a model for future efforts in adults.  The reason that we've not been successful in adult cancers is two-fold.  The first is that less than 5 percent of adults are on clinical trials; the second is that clinical trials have been trial and error rather than targeted.  A greater emphasis on basic science research so that de novo trials can be developed rather than just adding new drugs to existing drug regimens is critical.