DRUG MAY AID CANCER TREATMENT : AMGEN SUBSTANCE LESSENS SIDE EFFECTS.

Byline: Steven J. Gorman Daily News Staff Writer

Medical researchers at UCLA and two other universities announced Sunday they have achieved promising results in the first human trials of a new drug designed to ease a severe side effect of chemotherapy in the treatment of cancer.

The drug, MGDF, produced by the Thousand Oaks biotechnology firm Amgen Inc. from a hormonelike substance that occurs naturally in humans, succeeded in quickly boosting depleted blood platelet levels in chemotherapy patients.

Helping the body recover more quickly from platelet depletion, a side effect from chemotherapy, would permit doctors to administer higher doses of anti-cancer drugs at more frequent intervals without endangering the patient.

``In the field of oncology, this is felt to represent a very important advance,'' said Dr. Judith Gasson, a resident of Calabasas and director of the UCLA Jonsson Comprehensive Cancer Center.

The study was presented Sunday at a meeting of the American Society of Clinical Oncology in Philadelphia.

One side effect of chemotherapy and radiation treatments is a severe reduction in blood platelets, the cells necessary for blood to clot and for wounds to heal.

Drastic depletion of platelet counts can trigger internal bleeding, as well as bleeding from the nose and gums. The condition interferes with aggressive treatment of cancer and in severe cases can be life-threatening.

Chemotherapy patients are given transfusions to boost their platelet counts, but this poses a heightened risk of exposure to blood-borne diseases, such as hepatitis or AIDS. And ultimately, the transfusions will fail to work as the patients develop antibodies to donor platelets.

The success of MGDF, if confirmed in further trials, would mean the end of a decadelong search for a way to stimulate a patient's own production of platelets, said Gasson.

``It will allow physicians to give higher (chemotherapy) doses and more doses, and that always increases the chances of getting rid of all the cancer cells,'' Gasson said. ``The more chemo they give, the more cancer killed.''

Gasson said drugs have been available for a decade to stimulate the production of disease-fighting white blood cells damaged by chemotherapy, but a similar treatment for damaged blood platelets has been elusive.

The most significant results of the study, involving 51 patients with newly diagnosed inoperable lung cancer, were that MGDF lowered the duration and severity of platelet depletion due to chemotherapy.

For those patients given the drug, the median return time to initial platelet counts was 13 days after their chemotherapy treatment, compared with 28 days for patients given a placebo.

In addition, the median platelet count for all the MGDF patients was 70 percent higher than the placebo group following chemotherapy.

MGDF was first administered to humans in the United States by researchers at the UCLA cancer center. The trials also included patients at Emory University's Winship Cancer Center in Atlanta and the Duke University Medical Center in North Carolina.

MGDF is produced by the body naturally to stimulate the production of blood platelets in bone marrow.

Development of the drug was made possible when researchers isolated the gene that encodes the agent, allowing them to produce it in mass quantities through biotechnology, Gasson said.

The drug is manufactured by Amgen, a biotech firm that announced recently it plans to increase its 4,300-member work force in Thousand Oaks by 50 percent over the next two years. MGDF also is manufactured by Kirin Pharmaceutical Division in Tokyo.

The initial trial established the safety of MGDF. Future trials will be aimed at confirming the efficacy of the drug and its optimum dose, Gasson said.

She said if the initial results of the drug hold up, MGDF could be widely available in two to five years.

Gasson said the drug presumably could be used to ease platelet reduction in cancer patients undergoing radiation treatment, as well as chemotherapy, and has potential applications for treating other forms of cancer besides lung cancer.

The combination of MGDF and similar agents agents already available ``might make it possible to grow the patient's own bone marrow in the laboratory and reinfuse it in that patient, perhaps to treat leukemia and breast cancer,'' she said.

This would reduce the risk of immune-system rejection that accompanies transplants of bone marrow taken from donors, she said.