Human Genome Sciences Inc. said yesterday that it had entered advanced human tests with a drug that could prevent one of the worst complications of cancer treatment, the severe mouth and intestinal sores that force many people to interrupt chemotherapy.

The Rockville company said the injectable drug, which would eventually be sold under the trade name Repifermin, had proven safe in tests of healthy volunteers. The new tests, in patients undergoing a particularly aggressive cancer regimen, are aimed at determining whether the drug works in people.

The compound is one of the more intriguing under study in the biotechnology industry, mainly because animal tests have suggested it is an exceedingly potent wound-healing factor. Separate tests of the drug are underway as a topical treatment for skin wounds.

The new research calls for injecting the drug and allowing it to circulate throughout the body to determine whether it can reduce the open, bleeding mouth and intestinal sores known as mucositis. Animal research suggests the strategy makes sense because only those cells near the site of wounds are sensitive to the drug's effects.

William Haseltine, chairman and chief executive of Human Genome Sciences, said yesterday the animal research on the drug had been "nothing short of phenomenal." Portions of the upper intestine, colon and bladder that had been completely stripped of their lining were restored to "full integrity" within two or three days, he said.

Repifermin is a genetically engineered version of a growth factor, Keratinocyte Growth Factor-2, normally found at low levels in the body. Cells near certain types of wounds appear to undergo biochemical changes that make them extremely sensitive to the growth factor. Human Genome Sciences is working on the theory that more of a good thing will be a better thing, spurring faster healing.

There is, however, a theoretical risk with drugs of this type, many of which are under investigation by the biotechnology industry. If cancer cells are sensitive to their effects, they could actually spur faster cancer growth.

Haseltine said cancers tested so far don't seem to have the components needed to respond to Repifermin, lessening the concern somewhat.

The drug will be tested initially in people undergoing a particularly daunting cancer regimen involving transplantion of their own bone-marrow cells. The company hopes to expand the tests to other types of cancer treatments. People who want to know if they are eligible can contact the company at 301-309-8504, extension 3550.

Human Genome Sciences shares, which have jumped 106 percent since Nov. 1, closed at $193.12 1/2 yesterday, down 0.52 percent from Friday's close.