Disappointing Progress Report on Iniparib Clinical Trials

Sanofi-aventis recently announced disappointing results from a Phase 3 clinical trial for patients with metastatic triple negative breast cancer using the investigational drug iniparib, which belongs to a class of drugs called PARP inhibitors. The drug was used in a randomized trial with patients receiving gemcitabine and carboplatin with or without iniparib. No improvement in overall survival or progression-free survival was found in patients taking iniparib as a first-line therapy (the initial, or first, therapy used in a person’s cancer treatment). Improvement was seen in patients receiving iniparib as a second- or third-line therapy.

Many patients were very hopeful after the positive Phase 2 results, so the Phase 3 results surprised some. It is important to remember the difference in the purpose and scope of the trials. Phase 2 trials involve fewer patients and aim to identify the appropriate dosage to ensure a drug is effective and safe. Phase 3 trials are much larger and are intended to confirm the effectiveness of a drug, as well as provide information for physician labeling.

Sanofi-aventis has indicated patients who are currently enrolled in Phase 2 or Phase 3 trials for metastatic breast cancer should not expect disruption of access to this drug, regardless of whether these patients are receiving it as a first-, second- or third-line treatment.

Patients who are currently enrolled in the Expanded Access Protocol (EAP) can continue to get iniparib if they are second- or third-line patients. A new consent form will be required to continue. However, the recommendation from sanofi-aventis, based on the analysis of the Phase 3 data, is that first-line patients discontinue treatment with iniparib. If patients and their physicians think iniparib should be continued based upon the individual’s potential risk and benefit, a new consent form will be required. The enrollment process for patients who are waiting to be enrolled in the EAP program has not changed for second-, third- and fourth-line patients. No new first-line patients will be accepted into the EAP.

Sanofi-aventis has no current plans to discontinue the EAP, but will be meeting with the U.S. Food and Drug Administration (FDA) to discuss the structure and length of the program. They will also continue to evaluate the Phase 3 results to gain a better understanding and to identify the patients who may potentially benefit from iniparib.

Sanofi-aventis is communicating with physicians who have enrolled patients on the trial, is seeking guidance from the FDA about sharing data with patient groups and has submitted an abstract for the American Society of Clinical Oncology (ASCO) meeting in June 2011 to report these findings.

Sanofi-aventis plans to continue its ongoing clinical trials with iniparib for breast, lung and ovarian cancers.

About the author

Susan G. Komen has written 343 articles for Susan G. Komen® | Blog

Nancy G. Brinker promised her dying sister, Susan G. Komen, she would do everything in her power to end breast cancer forever. In 1982, that promise became Susan G. Komen and launched the global breast cancer movement. Today, Komen is the world’s largest grassroots network of breast cancer survivors and activists fighting to save lives, empower people, ensure quality care for all and energize science to find the cures. Thanks to events like the Komen Race for the Cure®, we have invested more than $1.9 billion to fulfill our promise, becoming the largest source of nonprofit funds dedicated to the fight against breast cancer in the world.