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| |  ASCO-DG Dispatch: New Anti-Cancer Drugs Will Offer Alternative To Chemo, Surgery By Robert H. Carlson Special to DG News LOS ANGELES, CA -- May 21, 1998 -- Cancer is a complex disease that can be attacked at many levels, but scientists are still searching for that novel compound which will spare patients the rigors of chemotherapy, radiation or surgery. Scores of new drugs using new anti-tumour strategies were discussed here at the American Society of Clinical Oncology's 34th annual meeting. New ideas such as antibodies to oncogenes (such as herceptin) and anti-angiogenesis therapy (described below) are causing excitement within the oncology community. Meanwhile, screening and prevention still seem to be the most productive efforts clinicians can offer to patients. Screening Reduces Prostate Cancer Deaths: Data presented here from a large Canadian study show that screening and early intervention resulted in a 69 percent reduction in deaths from prostate cancer. The eight-year study randomised 46,193 men from the Quebec City electoral rolls to annual screening with PSA and digital rectal exam (and transrectal echography if results from those two tests proved suspicious), or to no screening. Fernand Labrie, MD, PhD, director of research at the Centre de Recherche du Pavillon CHUL, Sainte-Foy, QC. reported a mortality rate of 48.7/100,000 men-years due to prostate cancer among the 38,056 men not screened, compared to only 15.0/100,000 men-years among the 8,137 men screened. "Screening based largely on PSA tests is a highly efficient means of diagnosing localised prostate cancer and reducing cancer death at a reasonable cost," Dr. Labrie said. Questions arose here about potential skewing of data due to the mechanism of patient recruitment and the researchers said further trials will be necessary to confirm the data. Angiogenesis: The popular media is calling Dr. Judah Folkman, The Man Who May Have Cured Cancer, because his labours in anti-angiogenesis research are finally bearing fruit. Progress was described here on several antiangiogenic agents which attempt to block or inhibit the growth of abnormal blood vessels in and around malignant tumours. If successful, these drug should be able to halt the growth of micro-metastases in advanced disease as well as shrink larger tumours. Endostatin and angiostatin were conspicuously absent from this meeting, reportedly because of slow manufacture of clinical-trial quantities. One promising new agent which attacks a critical endothelial growth factor in tumours was discussed. Michael Gordon, MD, Indiana University School of Medicine, said a Phase-I trial showed that a recombinant human monoclonal antibody against vascular endothelial growth factor (called anti-VEGF-MAb) was well-tolerated among a group of 25 patients with metastatic cancers. After four treatments in 72 days, 13 patients had stable disease and one patient with renal cell carcinoma had a 39 percent reduction in tumour size. Based on anti-VEGF-MAb's activity in animals, researchers hope these slim clinical responses due solely to anti-angiogenic activity will turn substantial when anti-VEGF-MAb is used on longer schedules and combined with chemotherapy. Another anti-angiogenic drug, TNP-470 is much further along in development. William Stadler, MD, University of Chicago, said TNP-470 has been shown to slow the growth of metastatic renal-cell carcinoma, a disease which is resistant to standard chemotherapy but also very vascular. Sixteen weeks into his Phase-II trial of 20 advanced-disease patients, two have had minor lung-tumour responses and five have had no progression. The mild toxicity and prolonged progression-free period seen in these heavily pre-treated patients are encouraging, Dr. Stadler said.
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