Higlights Of the American Society Of Clinical Oncology conference, Day 3
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Reported by Melissa Stoller
Though there were no Central Nervous System sessions on Monday, I saw three posters that have special significance for the BT community. Most important, CTP-11 should probably not be taken concurrently with thalidomide. Following a suggestion that thalidomide may be used to decrease GI toxicity of CPT-11 (Govindarajan, Lancet 2000; 356:566) Allegrini (Abstract 559) investigated the interactions between thalidomide and CPT-11. He found that thalidomide does, indeed, alleviate CPT-11 induced diarrhea, but this is a result of reduced metabolism of CPT-11, and a decrease in the active metabolite SN-38 (though not in SN-38G, the glucuronide.) Though the clinical significance of this interaction is unknown, it would presumably result in tumor cells encountering less active drug.
Clarke (Abstract 531), on the other hand, found no interaction and no reduction in plasma SN-38 with concurrent treatment of CPT-11 and Chrysin, an herbal flavanoid used by bodybuilders. Treatment with Chrysin reduced the frequency of diarrhea from 35% to 10%, and appears to be a safe and promising treatment for CPT-11 induced diarrhea.
I was looking forward to seeing the data presented on another natural agent, Neovastat, an anti-angiogenic agent derived from shark cartilage. Though Aeterna, its developer, had planned on presenting data from their Phase III study in a variety of advanced cancers, a VP for the company told me that the data are not yet available and the poster was uninformative. Nevertheless, it was attracting media attention.
Finally, phase I studies are testing the effects of high-dose celecoxib, 600-800 mg/day, in a variety of tumors. I questioned a number of the authors, and none had seen any particular side effects associated with this dosing, though the longest period any patient had been taking Celebrex at this level was 18 months.
Tomorrow is the last day of the ASCO conference. At the close of the meeting, all abstracts will be available on their website, ASCO.org. In some cases, data I report may differ from those in the abstracts. This may be the result of my error, but is more likely to reflect the updated statistics presented at the meeting. The abstracts are submitted many months in advance and additional data have often been collected.