fizer has decided to discontinue a late-stage trial of its oncology treatment Sutent as a possible treatment for colon cancer.

The company has pulled the SUN 1122 Phase III that evaluated Sutent (sunitinib) plus FOLFIRI (irinotecan plus 5-fluorouracil and leucovorin) versus the latter the chemotherapy regimen alone for the first-line treatment of metastatic colorectal cancer. The decision was taken because the trial’s independent data monitoring committee that the Sutent/FOLFIRI combo “would be unable to demonstrate a statistically significant improvement in the primary endpoint of progression-free survival compared to FOLFIRI alone”, Pfizer said. No new safety issues were identified.

Mace Rothenberg at Pfizer’s Oncology Business Unit said that “we are disappointed with this result, but trial successes and failures are an integral part of cancer drug development and contribute to a growing body of knowledge on improving patient care”. He added that Pfizer “remains committed to developing new agents for colorectal and other GI cancers with ongoing clinical studies evaluating other agents in its pipeline”.

A month ago, the drug major pulled a Phase III study that evaluated Sutent plus paclitaxel versus Roche’s blockbuster Avastin (bevacizumab) plus paclitaxel for the first-line treatment of patients with advanced breast cancer. However just last week, Pfizer noted that a study involving154 patients with advanced pancreatic islet cell tumours was stopped early because the median progression-free survival seen with Sutent was 11.1 months compared with 5.5 months in the placebo group.

Sutent is approved to treat advanced renal cell carcinoma, and gastrointestinal stromal tumours for patients who can't tolerate Novartis’ Glivec/Gleevec (imatinib). Pfizer is also performing Phase III studies of the drug in advanced non-small cell lung, colorectal and prostate cancers, as well as in hepatocellular carcinoma.

EU probe into Wyeth merger extended
Meantime, the European Commission has extended its antitrust review into Pfizer's proposed $68 billion merger with Wyeth to July 20 from the orginal July 6 date. The extension is due to “commitments” offered by the companies which have not been specified by the Commission but are likely to involve possible divestments for competitive reasons.

Pfizer has previously stated that it may divest certain assets from its animal health unit.