The National Institutes of Health will sponsor human tests of an experimental Guilford Pharmaceuticals Inc. drug that was rejected last year by Amgen Inc. after it proved ineffective at reversing Parkinson's disease symptoms, the Baltimore-based company said yesterday.

The National Institute of Neurological Disorders and Stroke, a division of the NIH known as NINDS, will oversee testing of GPI 1485 in a pilot study to determine if it's promising enough to move into a final-stage clinical trial. Guilford will supply the drug and a placebo for the test.

Unlike Amgen's more ambitious trial, which sought evidence that the drug reversed Parkinson's motor symptoms, the institute plans to look for signs that the drug slows progression of the disease, said Dr. Bernard Ravina, clinical trial program director for NINDS. He said GPI 1485 is one of up to six drugs the institute plans to test in pilot studies seeking evidence that they could slow progression.

"Our feeling is that there is still some promise based on preclinical work," Ravina said, referring to animal studies of the drug. He said Amgen's studies also showed it appeared safe.

The studies are expected to start next year and last up to two years, including follow-up. Ravina expected 60 to 70 patients to be involved in the GPI 1485 pilot study at up to 42 sites in the United States and Canada. Guilford also has its own Phase II trial of the drug.

Amgen returned rights to the Parkinson's disease drug and an entire family of similar drugs to Guilford in September 2001.

Shares of Guilford rose 10 cents to $3.41 on the Nasdaq stock market yesterday.