Cambridge-based Millennium said Monday the decision would enable patients being treated with another drug in the trial to switch over to Velcade.
Millenium said it would share data from the study at a medical conference during the first half of next year, after originally planning to release the information in 2005.
Millennium said patients suffering from multiple myeloma, a cancer of the blood, who received Velcade showed a "statistically significant improvement" compared to those receiving high-dose dexamethasone. The decision allows dexamethasone patients in the trial to switch over to Velcade.
Millennium is developing the drug with Johnson & Johnson Pharmaceutical Research & Development L.L.C.
Federal regulators gave Velcade an expedited approval last May based on a smaller trial.