Millennium Pharmaceuticals Inc. put the brakes on a Phase II study of Velcade in colorectal cancer patients.

The Cambridge, Mass.-based company said both arms of the study failed to meet prespecified efficacy criteria needed for continued accrual. The trial was examining the use of Velcade (bortezomib) either alone or in combination with Camptosar (irinotecan) in Camptostar-refractory patients with metastatic colorectal cancer.

But the company said it will not abandon the drug in colorectal cancer altogether.

"We're still looking at it in non-refractory colon cancer and different combinations," Kelly Lindenboom, Millennium's senior manager of corporate communications, told BioWorld Today. "We're certainly not closing the door on colon cancer altogether. But in terms of this combination and setting, we will not pursue it any further."

She declined to specify the missed endpoints, though the year-old study's primary endpoint evaluated tumor response. Secondary endpoints included time to disease progression and survival.

Patients in the study who experienced a clinical benefit may continue to receive treatment with the proteasome inhibitor. Additional investigator-sponsored studies, as well as trials sponsored by the National Cancer Institute in Bethesda, Md., examining Velcade's use in combination with other agents for non-refractory colorectal cancer are ongoing or planned, as well.

Already approved for multiple myeloma, the injectable drug also is being studied in other oncology indications. Millennium said it is being studied in more than 50 ongoing or planned clinical trials in both hematologic and solid tumors, including Phase II programs for non-Hodgkin's lymphoma and non-small-cell lung cancer.

Velcade is partnered with Johnson & Johnson Pharmaceutical Research & Development LLC, a unit of New Brunswick, N.J.-based Johnson & Johnson. Millennium is responsible for its U.S. commercialization, while various Johnson & Johnson companies will distribute it elsewhere.

Leerink Swann & Co. in Boston predicts Velcade revenue from hematologic malignancies eventually could bring Millennium more than $300 million per year. The firm estimates Velcade's fourth-quarter revenue from 2003 to be $25.4 million.

Millennium's stock (NASDAQ:MLNM) dipped $1.16 Tuesday to close at $17.85.