New treatment regimen shows clinical benefit in advanced colon cancer

May 18, 2011, Georgetown University Medical Center

A new treatment regimen for patients with metastatic colon cancer appears to offer clinical benefit even when used after multiple other treatments have failed, say research physicians at Georgetown Lombardi Comprehensive Cancer Center, a part of Georgetown University Medical Center.

The research team found that combining a PARP inhibitor with chemotherapy () offers significant benefit in patients who had no further treatment options. However, the study is small, and does not include a comparison arm, so further investigation is needed, they add. The study will be presented in an oral session on Saturday, June 4th, at the 2011 annual meeting of the American Society of Clinical Oncology in Chicago.

PARP, short for "poly (ADP-ribose) polymerase" is a key part of a cell's apparatus, and is important for protecting our normal cells against DNA damage. However, become resistant to chemotherapy in part by increasing PARP expression and thus rapidly repairing intentionally caused by chemotherapy. PARP inhibitors are designed to overcome a cancer cell's ability to repair the damaged DNA. (They are showing promise in both breast and , and are being studied in a variety of other cancer types).

In this clinical study, doctors administered a potent DNA-damaging chemotherapy, temozolomide, with a PARP inhibitor called ABT-888. The theory is that ABT-888 will diminish the ability of these cancer cells to fix the damage that was just inflicted by the temozolomide, pushing the cancer into a death spiral.

"This is a classic one-two punch: the chemotherapy damages the cancer cells and the PARP inhibitor prevents it from fixing itself, leaving the cell to die," says lead author, Michael Pishvaian, M.D., Ph.D., an assistant professor at Georgetown Lombardi.

This single-arm, phase II study enrolled 49 patients with metastatic disease who were not eligible for surgery and had exhausted all of the standard therapies currently used. Despite having advanced cancer, all study participants were still active at work or home. Researchers found the drug combination controlled cancer growth for nearly six months in 23 percent of the patients, with two patients having a significant reduction in their tumor burden (partial response).

Pishvaian explains, "The treatment was extremely well tolerated, so to have a period of six months with no tumor growth, but also no significant side effects was really meaningful for the patients."

In addition, researchers were able to collect samples of the patients' tumors for further molecular analysis. "By testing tissue samples and identifying their molecular fingerprints, perhaps we can identify which patient subgroups are most likely to respond to this new therapeutic combination," concludes Pishvaian.

Explore further: Heat helps cancer drugs battle cancer

Related Stories

Heat helps cancer drugs battle cancer

May 10, 2011
(PhysOrg.com) -- Localized hyperthermia has been used occasionally with cancer drugs for some time, but until now, the reason it helps has been a mystery. In a report in the Proceedings of the National Academy of Sciences, ...

Recommended for you

T-cells engineered to outsmart tumors induce clinical responses in relapsed Hodgkin lymphoma

January 16, 2018
WASHINGTON-(Jan. 16, 2018)-Tumors have come up with ingenious strategies that enable them to evade detection and destruction by the immune system. So, a research team that includes Children's National Health System clinician-researchers ...

Researchers identify new treatment target for melanoma

January 16, 2018
Researchers in the Perelman School of Medicine at the University of Pennsylvania have identified a new therapeutic target for the treatment of melanoma. For decades, research has associated female sex and a history of previous ...

More evidence of link between severe gum disease and cancer risk

January 16, 2018
Data collected during a long-term health study provides additional evidence for a link between increased risk of cancer in individuals with advanced gum disease, according to a new collaborative study led by epidemiologists ...

Researchers develop a remote-controlled cancer immunotherapy system

January 15, 2018
A team of researchers has developed an ultrasound-based system that can non-invasively and remotely control genetic processes in live immune T cells so that they recognize and kill cancer cells.

Dietary fat, changes in fat metabolism may promote prostate cancer metastasis

January 15, 2018
Prostate tumors tend to be what scientists call "indolent" - so slow-growing and self-contained that many affected men die with prostate cancer, not of it. But for the percentage of men whose prostate tumors metastasize, ...

Pancreatic tumors may require a one-two-three punch

January 15, 2018
One of the many difficult things about pancreatic cancer is that tumors are resistant to most treatments because of their unique density and cell composition. However, in a new Wilmot Cancer Institute study, scientists discovered ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.