Researchers writing in the British journal The Lancet said theycannot yet recommend the growth factors G-CSF, GM-CSF orIL-3 for routine use in any malignant disorder.

An editorial published Saturday in The Lancet reviewed theclinical potential of Amgen Inc.'s granulocyte colonystimulating factor (G-CSF), and Immunex Corp.'s granulocytemacrophage colony stimulating factor (GM-CSF) andinterleukin-3 (IL-3).

Because of G-CSF's expense, the editors wrote, "its use isunlikely to be sanctioned unless it can be proven to be cost-effective (by reducing inpatient time or antibiotic costs) or toincrease cancer cure rates by allowing more-intensivetreatment."

Immunex of Seattle in June published results showing that itsLeukine GM-CSF hastens recovery after bone marrowtransplants for cancer therapy. The average cost of a 21-daycourse of therapy is $3,400.

Amgen of Thousand Oaks, Calif., two weeks ago showed that G-CSF cut the duration of neutropenia, the lowering of whiteblood cell counts, in the treatment of small-cell lung cancer. Apatient may receive Neupogen G-CSF for a week to 12 daysfollowing chemotherapy at a cost of $750 to $1,300.

Both companies have emphasized the cost savings gained whentheir respective treatments cut hospital stays.

Compared with the United States, said Kidder, Peabody analystRobert Kupor, Britain is more careful about rationing healthcare. "They've hardly used Epogen," Kupor said, referring toAmgen's erythropoietin, which ameliorates anemia in patientswith kidney failure. "They have the philosophy: 'We can't affordto give everything to everybody.' "

Kupor said the British viewpoint echoes mainstream physicianresponse to the cost of G-CSF. "A lot of doctors feel it'sinappropriate to give this to everyone," he said.

The British editors noted that G-CSF may be a useful adjunctin curative chemotherapy for some tumors, such as lymphomas,germ-cell tumors (testicular and ovarian cancer), and somechildhood malignancies, where more-intensive chemotherapyis used and the higher doses increase cure rates.

They also referred to testing of the factors alone and incombination in cancer treatment strategies where their useappears to promise an increased rate of remission.

But doubts remain about the possible role of stimulatingfactors in cancer. Although no reports show that the factorshasten the progress of cancer, the editors wrote, receptors forG-CSF and GM-CSF are present on the blast cells of acutemyeloid leukemia and stimulate their growth in test tubes. G-CSF receptors have also been found on small cell lung cancercells and on other malignant cells.

-- Roberta Friedman, Ph.D. Special to BioWorld

(c) 1997 American Health Consultants. All rights reserved.