Guilford Pharmaceuticals Inc. said yesterday that it has formally submitted additional data to the Food and Drug Administration to support expanded use of its only marketed product, the brain cancer treatment Gliadel.

The Baltimore company hopes the data - which appears to show improved long-term survival for certain patients who get Gliadel - prompts the FDA to reverse its earlier decision to reject expanded marketing of the chemotherapy-packed wafer. Gliadel is implanted in the cavity left when a brain tumor is surgically removed.

It currently is approved for use only during second surgeries, necessitated when a particularly aggressive kind of tumor - malignant glioma - grows back. Guilford's earlier attempt to get the wafer approved for use during initial brain-tumor surgeries for malignant glioma was rejected by the FDA in March.

But there is reason for investors to be guardedly optimistic that the FDA might change its mind, said Brian D. Rye, an analyst with Raymond James & Associates.

"The FDA is at least interested enough to take a closer look," Rye said, referring to the fact that the FDA reviewed the data informally before suggesting Guilford formally submit it in the form of an amendment. "I'm certainly hopeful that the follow-up data is convincing."

The data, which Guilford previously publicized, appears to show that Gliadel reduces the risk of dying by 27 percent over three to four years when it's given to patients during initial surgery. Guilford came up with the data by doing long-term follow-up analysis of patients involved in a Phase III trial that was concluded in June 2000.

About 228 of the 240 patients who enrolled in the trial from December 1997 to June 1999 had died by last August. One patient couldn't be located. Of the 11 patients known to be alive, nine had received a Gliadel wafer. Two had gotten a placebo.

"We believe these new data provide evidence of a long-term survival benefit ... ." Guilford Chief Executive Officer Craig R. Smith said in a statement. "We're very encouraged by these new data and look forward to continuing to work with FDA to facilitate their review."

Such a review could take up to six months, though Rye said he's hopeful the agency - already familiar with Gliadel from previous submissions - will complete its review quickly.

Shares of Guilford lost 33 cents yesterday to close at $4.68 on the Nasdaq stock market.