GPC Biotech, Cell Genesys Soar on Cancer Therapy Test (Update4) By Phyllis Carter
Munich, Aug. 23 (Bloomberg) -- Shares of GPC Biotech AG rose 12 percent and Cell Genesys Inc. as much as 17 percent after the companies said their new genetic cancer treatment killed multiple types of cancer cells in mouse studies.
GPC, based in Munich, rose 6.15 euros to 59.50 on the Neuer Markt. Its U.S.-based partner, Cell Genesys, rose 3 1/2 or 15 percent to 26 9/16 in late Nasdaq trading.
The companies hope the product will one day compete in the $5 billion market for cancer treatments, and investors said the results -- which showed the treatment killed cancer cells from an array of human-tumor types implanted in mice -- support further research. Still, they cautioned against premature enthusiasm for an experimental treatment in the earliest stages of development.
``Nobody should ever feel confident on the basis of animal studies but it's very intriguing data,'' said Jim McCamant, an analyst with the Medical Technology Letter and president of the American Health Care Fund, which holds 13,000 shares of Cell Genesys.
The biotechnology companies said the therapy killed cancer cells in 12 of 14 types of human tumors, and didn't affect normal surrounding tissue.
The treatment is comprised of two anti-cancer genes that are fused together and then delivered to cancer cells using a benign virus as a vehicle. The fusion appeared to block tumor cells' ability to multiply and kill cells outright, and showed signs of thwarting blood-vessel growth that tumors need to thrive.
Targeting Differences
The treatment is one of a wave of experimental therapies designed to target differences between cancerous and healthy cells. Researchers and companies hope targeted treatments will be more effective, with fewer side effects, than traditional therapies.
``I've seen that efficacy or a lot better in mouse studies of drugs that never made it to market. . . . What I did like was the apparent lack of toxicity to normal cells,'' said Marty Bukoll, an analyst with Northern Trust Corp., which holds about 102,000 shares of Cell Genesys. ``Patients in the future are no longer going to be willing to tolerate being extremely sick just to go through cancer therapy.''
The therapy worked in cells containing normal p53 genes as well as mutated p53 genes, the companies said. The naturally occurring p53 gene prompts cancer cells to self-destruct, but it's mutated in more than half of human cancer cases. Unlike most cancer treatments, the GPC-Cell Genesys treatment doesn't need the p53 gene to function.
In the mice studies, the GPC-Cell Genesys drug p27/p16 blocked tumor progression in 50 percent of treated animals, which the companies said was ``highly statistically significant.''
The research is part of a major focus on identifying and developing treatments based on tumor suppressor genes.
``We are still evaluating genes we want to take into human testing, which is a couple years away,'' said Stephen Sherwin, chief executive of Cell Genesys. ``It's one of our early-stage programs, but it takes advantage of discovery of new genes, engineering of new genes, and continuing progress in gene therapy in delivering genes.''
Currently, several companies are developing cancer treatments that target the p53 gene tumor suppressor gene.
Onyx Pharmaceuticals Inc. is testing its drug ONYX-15, a genetically modified virus now in human studies designed to kill tumor cells lacking p53 tumor suppressor activity. When the virus finds those deficient cells, it kills them and spares cells that contain normal p53.
Onyx shares have more than doubled this year.
Last week, GPC said its first-half loss widened to 22 million euros ($20.1 million) as it hired more scientists in Europe and the U.S.
|