Avastin May Stop Rectal Cancer Spread

Patients in Study Show No Signs of New Cancer Growth in Area of Original Tumor

From the WebMD Archives

April 15, 2008 (San Diego) -- Adding the cancer drug Avastin to standard treatment stopped cancer spread in 22 of 24 patients with rectal tumors, researchers report.

The patients were given Avastin, chemotherapy, and radiation prior to surgery to have their tumors removed. Three years later, all the patients were alive and 91% had no signs their disease was getting worse.

And none had new cancer growth in the area of the original tumor, says Rakesh Jain, PhD, the Andrew Werk Professor of Tumor Biology at Harvard Medical School.

"I know of no other therapy in this patient population where we can even get close to 100% tumor control. Although this needs to be confirmed in a randomized trial against a placebo group, these are very impressive numbers," he says.

Avastin was one of several drugs that took center stage during the annual meeting of the American Association for Cancer research this week. Other researchers report that a drug that starves tumors of their blood supply shows promise for the treatment of one of the deadliest forms of brain cancer.

Still other researchers have had early success turbo-charging the body's own immune system to fight prostate cancer.

Avastin Fights Rectal Cancer

Avastin is already approved to treat metastatic colorectal cancer, advanced lung cancer, and metastatic breast cancer.

Its cancer-fighting abilities have been attributed to its ability to prevent tumors from growing new blood vessels, thereby choking them to death.

The new research in rectal cancer patients suggests that it works in another remarkable way as well: It also repairs remaining blood vessels, Jain tells WebMD.

"Some of the blood vessels are pruned away immediately. But the vessels that remain become less abnormal. This creates a less hostile environment so radiation and chemotherapy can work better," he says.

The researchers monitored the repair of blood vessels using imaging scans and blood tests for biomarkers known to be involved in cancer growth, according to Jain.

Experimental Drug Shows Promise for Brain Cancer

In a second study, the experimental drug cediranib helped shrink tumors and prolong the lives of people with a relatively common but often fatal type of brain cancer called glioblastoma.

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"These patients have a very poor prognosis, with fewer than 5% alive five years after diagnosis. There's a significant need for new therapies," says Tracy Batchelor, MD, executive director of the Stephen E. and Catherine Pappas Center for Neuro-Oncology at the Massachusetts General Hospital Cancer Center in Boston.

The researchers gave the pill to 31 people who had failed to respond to radiation, chemotherapy, and surgery.

After six months, about 25% were alive without signs that their cancer had grown or spread. That might not seem like much, but with traditional treatment, only about 15% of the patients would fare this well, Batchelor tells WebMD.

On average, participants lived for 227 days; the average time to tumor regrowth was 117. In contrast, people with glioblastoma given traditional treatment typically live only 175 days, and the average time to progression is usually 63 days, he says.

In addition, cediranib was found to alleviate brain swelling, "a huge problem with the type of cancer that makes patients stay on steroids for long periods of time," Batchelor says.

Two of the 31 patients had to stop taking cediranib due to drug-related fatigue. Other common, but manageable, side effects included high blood pressure and diarrhea.

Batchelor says the pill works similarly to Avastin, blocking the growth of new blood vessels that feed tumors and normalizing remaining vessels.

He says a larger trial that will pit cediranib plus standard chemotherapy against chemotherapy alone is scheduled to start enrolling patients this summer.

Using the Body's Immune System to Fight Prostate Cancer

In many ways, cancer is a malfunction of the body's immune system. Tumor cells often grow and spread because the body doesn't recognize them as foreign.

Two other teams of researchers are taking unique approaches to manipulate the immune system to recognize cancer cells as alien invaders that need to be wiped out.

First, they remove the brakes on the immune system. That's accomplished with a drug called ipilimumab. It blocks CTLA-4, a molecule on immune system cells that inhibits the immune response.

Then, they jump-start the immune system to attack the cancer -- in one case with a vaccine called GVAX and in the other, with a compound called GM-CSF.

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Both approaches curbed tumor growth in men with prostate cancer that hadn't responded to hormone therapy.

"This is a strategy we should pursue with great vigor," says Louis Weiner, MD, director of the Lombardi Cancer Center at Georgetown University in Washington, D.C. He was not involved with the work.

"Utilizing the immune system to attack cancer will probably be remembered as one of the cardinal accomplishments of this era of research," Weiner tells WebMD.

WebMD Health News Reviewed by Louise Chang, MD on April 15, 2008

Sources

SOURCES:

American Association for Cancer Research annual meeting, San Diego, April 12-16, 2008.

Rakesh Jain, PhD, the Andrew Werk Professor of Tumor Biology, Harvard Medical School.

Tracy Batchelor, MD, executive director, Stephen E. and Catherine Pappas Center for Neuro-Oncology, Massachusetts General Hospital Cancer Center, Boston.

Lawrence Fong, MD, University of California, San Francisco.

Saskia J.A.M. Santegoets, PhD, Vrije Universiteit Medical Center, Netherlands.

Louis Weiner, MD, director, Lombardi Cancer Center, Georgetown University, Washington, D.C.

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