Chemotherapy Gets Re-Engineered
Cancer Drugs Are Modified
In an Effort to Cut Toxicity
And Increase Effectiveness
By DAVID P. HAMILTON
Staff Reporter of THE WALL STREET JOURNAL
January 11, 2005
Cancer patients may soon have a new set of treatment options: Re-engineered forms of traditional cancer-chemotherapy drugs with fewer toxic side effects and possibly improved effectiveness.
The first such drug won approval from the Food and Drug Administration Friday. Abraxane, to be sold by American Pharmaceutical Partners Inc., Schaumburg, Ill., is a version of the widely used breast-cancer chemotherapy Taxol, known generically as paclitaxel.
Abraxane, which consists of paclitaxel embedded in tiny particles of a natural human protein called albumin, appears to sidestep some of Taxol's more-serious side effects. In particular, Taxol must be administered with a castor-oil based solvent called Cremophor that can trigger serious allergic reactions, requiring cancer patients to take steroids and other immune-suppressing drugs prior to chemotherapy. Since Abraxane doesn't need solvents such as Cremophor, patients can skip the immune-suppressing treatment.
Other such drugs may not be far from the market. Cell Therapeutics Inc., Seattle, says it expects to release data from the first large-scale human tests of its own reworking of paclitaxel within the next three months or so. The Cell Therapeutics drug, called Xyotax, consists of paclitaxel bound into a ladder-like molecule called a polyglutamate polymer, which the company believes can more easily infiltrate tumors.
Although somewhat further from possible commercialization, NeoPharm Inc., Lake Forest, Ill., is working on a form of paclitaxel it calls LEP-ETU. That drug, whose name stands for "liposomal paclitaxel easy-to-use," encases paclitaxel in a fatty particle called a liposome. LEP-ETU has gone through a small-scale test in humans, and is undergoing tests to demonstrate pharmocologic activity equivalent to Taxol.
All three of these drugs are designed to reduce the dangerous side effects associated with paclitaxel, which can also include a life-threatening suppression of infection-fighting white blood cells and painful, although sometimes temporary, nerve disorders. In addition, supporters of these new drugs hope that it will be possible to treat patients with higher effective doses of the chemotherapy drug, potentially making treatment more successful.
Yet these drugs also have significant difference that will affect how they are used in cancer treatment if approved. Abraxane, for instance, was approved as a new generic form of paclitaxel. American Pharmaceutical's decision to take that route sped the official approval of the drug, but raised doubts among some doctors and investors because it abbreviated testing of Abraxane. In particular, there are no data to indicate whether Abraxane helps cancer patients live longer than those treated with Taxol.
Cell Therapeutics, by contrast, is seeking approval of Xyotax as a new drug in its own right, a lengthy and expensive process. If approved, however, Xyotax will have been subjected to much more stringent testing, including trials that should determine whether it offers a survival advantage over Taxol.
For instance, several major trials of Xyotax in lung cancer are expected to show whether the drug can extend survival either alone or in combination with other chemotherapy. The early signs are good, according to Cell Therapeutics Chief Executive James Bianco. Although company officials don't know specifically whether the patients receiving Xyotax are living longer, average survival of all patients in at least one trial appears to be significantly longer than expected, Dr. Bianco said.
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Such survival data is generally considered the "gold standard" for judging the efficacy of cancer treatments.
(cont on next post)
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