Clinical trial of PARP Inhibitors open to TNBC patients

From a news release from the Baylor College of Medicine:

HOUSTON -- (January 25, 2010) -- Breast cancer patients who have triple negative breast cancer, an aggressive form of the disease, that has spread to other parts of the body, are being asked to participate in a clinical study of a promising new treatment called PARP inhibitors.

Researchers from the Lester and Sue Smith Breast Center at Baylor College of Medicine will conduct the study at both the Baylor Clinic and the Harris County Hospital District's Ben Taub General Hospital.

“This is a very important study,” said Dr. Mothaffar Rimawi, assistant professor in the Smith Breast Center and the principal investigator of the study. “This type of cancer does not have many therapeutic options, other than standard chemotherapy, and is associated with a very poor chance of recovering when the disease has spread to other parts of the body.”

Early results promising

DNA repair is an important process to maintain healthy cells. Cancer cells use this process to repair their DNA as well. However, in cancer cells, this process can be defective and the cancer cells become more dependent on an enzyme called PARP to repair their DNA.

There are multiple signaling pathways in normal cells. PARP inhibitors work by blocking the DNA repair signaling pathway, causing the cancer cell to accumulate DNA defects and die.

Very promising results from an early stage PARP inhibitor study were announced at the American Society of Clinical Oncology’s annual meeting in May 2009.

“In this randomized trial, there was a significant advantage in terms of progression-free survival in patients taking chemotherapy plus PARP inhibitors versus patients taking chemotherapy alone,” said Rimawi. Progression-free survival indicates the length of time in which the patient lives without cancer growth following treatment.

Phase III

The current study, a Phase III study, will be part of a national, multi-center, randomized trial using the same structure as the previous study.

This study hopes to better define those promising results in a large group of patients, Rimawi said.

The study will evaluate response in patients taking chemotherapy alone versus patients taking a combination of chemotherapy and PARP inhibitors.

“Patients getting chemotherapy alone will be switched over to the PARP inhibitor if the chemotherapy is not working so everyone will have a chance at receiving the new drug,” said Rimawi.

Study criteria

Interested participants must:

• Be diagnosed with stage four, metastatic (cancer spreading to other body parts) triple negative breast cancer
• Be female over the age of 18
• Not be pregnant or breastfeeding
• Have no other diagnosis of cancer five years or more in the past, with the exclusion of non-melanoma skin cancer
• Have no prior treatment with PARP inhibitors or the following treatments: gemcitabine, carboplatin, cisplatin.

For more information on this study or to enroll, please contact BCM coordinator Claudette Foreman at 713-798-7315 or caforema@bcm.edu.