Dramatic outcomes in prostate cancer study | Arthritis Information
Just thought that this was too good to not post.
Mayo researchers: Dramatic outcomes in prostate cancer study
Two Mayo Clinic patients whose prostate cancer had been considered inoperable are now cancer free thanks in part to an experimental drug therapy that was used in combination with standardized hormone treatment and radiation therapy. The men were participating in a clinical trial of an immunotherapeutic agent called MDX-010 or ipilimumab. In these two cases, physicians say the approach initiated the death of a majority of cancer cells and caused the tumors to shrink dramatically, allowing surgery. In both cases, the aggressive tumors had grown well beyond the prostate into the abdominal areas. "The goal of the study was to see if we could modestly improve upon current treatments for advanced prostate cancer," says Eugene Kwon, M.D., Mayo Clinic urologist and leader of the clinical trial. "The candidates for this study were people who didn't have a lot of other options. However, we were startled to see responses that far exceeded any of our expectations."
The patients first received a type of hormone therapy called androgen ablation, which removes testosterone and usually causes some initial reduction in tumor size. Researchers then introduced a single dose of ipilimumab, an antibody, which builds on the anti-tumor action of the hormone and causes a much larger immune response, resulting in massive death of the tumor cells. Both men experienced consistent drops in their prostate specific antigen (PSA) counts over the following weeks until both were deemed eligible for surgery. Then, during surgery, came a greater surprise.
"The tumors had shrunk dramatically," says Michael Blute, M.D., Mayo urologist, co-investigator and surgeon, who operated on both men. "I had never seen anything like this before. I had a hard time finding the cancer. At one point the pathologist (who was working during surgery) asked if we were sending him samples from the same patient."
One patient underwent radiation therapy after surgery; both have resumed their regular lives. Further research is being planned to understand more about the mechanisms of the antibody and how best to use the approach in practice. The researchers, however, note the significance of their findings.
"This is one of the holy grails of prostate cancer research," says Dr. Kwon. "We've been looking for this for years."
[QUOTE=levlarry]...participating in a clinical trial of an immunotherapeutic agent called MDX-010 or ipilimumab. In these two cases, physicians say the approach initiated the death of a majority of cancer cells and caused the tumors to shrink dramatically, allowing surgery. In both cases, the aggressive tumors had grown well beyond the prostate into the abdominal areas.
The Prostate Cancer Outcomes Study (PCOS) was initiated in 1994 by researchers at the National Cancer Institute (NCI) to look at the impact that treatments for primary prostate cancer have on the quality of life of patients. PCOS is a collaboration with six cancer registries that are part of NCI's Surveillance, Epidemiology, and End Results (SEER) Program. (The SEER Program was established by NCI in 1973 to collect cancer data on a routine basis from designated population-based cancer registries in various areas of the country.)
PCOS is the first systematic evaluation of health-related quality-of-life issues for prostate cancer patients conducted in diverse health care settings and provides a model for similar large follow-up studies with other cancers. It is expected that better knowledge of the effects of treatment will help patients, families, and clinicians make more informed choices about treatment alternatives. PCOS will also provide some of the most detailed data collected to date on the patterns of
prostate cancer care.*
The results of PCOS will be published in various medical journals over the next few years. Those already published are listed at the end of this fact sheet.
Background
Prostate cancer is the single most common form of non-skin cancer in men in the United States. In the year 2003, an estimated 220,900 men will be diagnosed with prostate cancer, and some 28,900 will die of the disease. Prostate cancer exacts a particularly high toll on African-American men; mortality rates in African-American men are more than twice as high as rates in white men.
One of the problems facing prostate cancer patients is the uncertainty of many issues surrounding the management of the disease. It is not known, for instance, if the potential benefits of prostate cancer screening outweigh the risks, if surgery is better than radiation, or if treatment is better than no treatment in some cases.
Decisions about treatments are not easy to make. One problem is that it is difficult for a physician to predict whether a tumor will grow slowly with no health consequences to the patient, or will grow quickly and become life-threatening. Also, there are no randomized trials that compare the relative benefits of treating early stage patients with radiation therapy, radical prostatectomy (surgical removal of the entire prostate gland along with nearby tissues), or watchful waiting (following the patient closely and postponing aggressive therapy unless symptoms of the disease progress). About 80 percent of men diagnosed with prostate cancer have early stage disease.
In spite of all these uncertainties, it is known that certain treatments—radiation therapy, radical prostatectomy, or hormonal therapies—can have detrimental effects on urinary, bowel, and sexual functions. By collecting comprehensive data on the health outcomes of various treatments for prostate cancer, the PCOS will help patients, their families, and physicians make decisions about treatment options. Read full article
here.
This is a couple years old but explains how some cancers are allowed to grow. Some may find it interesting...................LEV
Doubling-Up on Cancer Drugs
When treating cancer, oncologists rarely depend on just one drug to destroy marauding tumor cells. Instead, they use what's often called a "cocktail therapy," administering a number of drugs, either together or sequentially, in the hopes that the combinations will somehow make each component more potent. Genentech's (DNA ) Avastin, for example, which cuts off the blood supply to tumors, is most effective when combined with other treatments.
Combination therapy may ultimately be the key to success for the emerging field of therapeutic cancer vaccines, designed to prod the body's immune system into attacking tumor cells. None of the 60 or so experimental vaccines currently in human trials have yet to prove unqualified efficacy at shrinking tumors, though there are signs that they can keep patients alive longer. But some scientists say an unusual new drug under development by Medarex (MEDX ) and Bristol-Myers Squibb (BMY ) may boost the tumor-killing ability of vaccines.
The Medarex drug, which goes by the unwieldy name of ipilimumab, doesn't attack cancer cells. Instead, it releases one of the brakes our bodies apply to the immune system so that disease-fighting drugs can do their job unimpeded. Ipilimumab may have little effect on a tumor on its own, says Alan Houghton, head of the tumor-immunology laboratory at Memorial Sloan-Kettering Cancer Center in New York, just as therapeutic vaccines have had little success in reducing the size of tumors. "Combine these two, and the immunological response goes to 100%," he says.
IMPORTANT INTERACTIONS Ipilimumab is currently in several clinical trials, alone and with other vaccines. The most closely watched is a small combination trial in the Netherlands with GVAX, an experimental prostate-cancer vaccine from Cell Genesys (CEGE ). Twelve patients have been treated so far, and in February the companies reported that five of the six patients who got the strongest dose saw their prostate specific antigen (PSA) level, a marker that can indicate the spread of prostate cancer, drop by more than 50%.
For four of those, the decline lasted for more than six months, and one patient experienced a decline for more than 12 months. That's considered a significant length of time for such sick patients. The combination also reduced the tumor size of one patient and reduced deadly bone metastases. GVAX has yet to prove such a strong anti-tumor reaction on its own.
The secret to the Medarex drug lies in a complex set of interactions in the immune system that's still not well understood. The immune system is designed to attack foreign invaders such as viruses and bacteria, sending out a barrage of so-called T-cells to destroy it through inflammation or some other reaction. But T-cells ignore the homegrown cancer cells, assuming that anything that arises inside the body must be benign.
ATTACKING TUMORS In recent years, scientists discovered that a part of the immune system called a dendritic cell, which marshals the T-cells to attack, can also send out a molecule called CTLA-4 that slows or stops those same T-cells. CTLA-4 protects the body from immune overreactions, but it also seems to be activated in the presence of mutant cancer cells—the dendritic cells want to protect those as well.
Ipilimumab is an antibody that blocks CTLA-4, removing the safety brake. It was discovered about seven years ago by James Allison, then at the University of California, Berkeley, and now head of the immunology department at Sloan-Kettering. Allison found that the antibody had the remarkable ability to completely knock out tumors in mice.
But the drug started attracting serious interest from the cancer community in 2003, after Glenn Dranoff at Dana-Farber Cancer Center in Boston gave the drug to patients with late stage melanoma and ovarian cancers, who had already received therapeutic vaccines with little benefit. All five patients given the most potent vaccine showed widespread death of cancer cells, proof that the immune system was on the attack.
PROCESS OF ELIMINATION The problem with drug combinations, however, is that it can be difficult to discover which component is doing what, especially in some clinical trials. Cancer-vaccine skeptics suggest that patients who benefited from a vaccine plus ipilimumab may have done just as well on the Medarex drug alone. "It can be effective in about 15% of melanoma patients, and it also has some reactivity in kidney cancer, but there's no evidence that a vaccine adds anything to it," says Steven Rosenberg of the National Cancer Institute, who has tested patients using ipilimumab.
Medarex and Bristol-Myers, which signed on to co-develop the drug in 2005, hope to settle the question with three large, late-stage trials of the drug, one where it's tested on its own, one where it's combined with chemotherapy, and one with a cancer vaccine. Results will start rolling in later this year. The drug is also being tested with a number of other vaccines in Phase 2 trials. Oncologists hope that, if and when it wins market-approval, they will be able to start experimenting with any number of drug combinations to see what it will contribute.
"We have become increasingly aware of the multiplicity of control points in the immune system," says Dana-Farber's Dranoff. "We have to figure out the relative importance of each of those control points, so we can come up with the optimal treatment. This is a problem that will require careful testing in patients."
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