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 (temozolomide) 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 DNA repair apparatus, and is important for protecting our normal cells against DNA damage. However, cancer cells become resistant to chemotherapy in part by increasing PARP expression and thus rapidly repairing DNA damage 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 ovarian cancers, and are being studied in a variety of other cancer types).