Pfizer is stopping another Phase III investigation, bringing its late-stage failures up to four for 2009 and five over the past year. This time the company is halting one of its trials studying sunitinib malate in advanced breast cancer but says that others evaluating different regimens will go on.
The discontinued study was looking at single-agent sunitinib versus single-agent capecitabine in patients who failed standard treatment. It was determined that treatment would not demonstrate a statistically significant improvement in the primary endpoint of progression-free survival.
The company is continuing to evaluate sunitinib as a single-agent and in combination with standard-of-care chemotherapy in specific patient populations with advanced breast cancer through three additional Phase III and two Phase II trials. Pfizer reports that it is also pursuing Phase III studies into the role of sunitinib in other solid tumors including advanced non-small-cell lung cancer, advanced colorectal cancer, advanced hepatocellular carcinoma, and advanced hormone-refractory prostate cancer.
Sunitinib, known as Sutent, is currently approved for both gastrointestinal stromal tumor after disease progression on or intolerance to imatinib mesylate. It is also sanction as a therapy for patients with advanced/metastatic renal cell carcinoma. The drug is an oral multikinase inhibitor and works by blocking molecular targets implicated in the growth, proliferation, and spread of cancer.
Pfizer’s late-stage programs have been looking bleak. On February 24, Pfizer called off Phase III studies of esreboxetine for fibromyalgia and PD 332,334 for generalized anxiety disorder, stating that neither would be better than currently approved treatments. Earlier that month, the company also nixed trials of axitinib in pancreatic cancer, because it did not improve survival. Last year, Pfizer ended development of its obesity therapy, citing the need for a slew of trials with no guarantee of approval.