Promising Data With Thrombopoietin

Researchers from ZymoGenetics, a subsidiary of Novo Nordisk, and the University of Washington in Seattle, USA have presented new findings regarding the use of thrombopoietin to restore platelet counts after chemotherapy or radiotherapy, at the American Society if Hematology meeting.

Animal data presented at the meeting showed that mice whose platelet counts had been reduced after a combined regimen of chemo- and radiotherapy had their platelet counts restored to normal levels by day 15 after treatment with TPO, while in placebo-treated mice the delay was 27 days. Previous studies using TPO were published in the journal Nature earlier this year, but in these cases only healthy mice were assessed (Marketletter June 20).

The new experiment mimics more closely what is expected to be the clinical utility for TPO, the treatment or prevention of thrombocytopenia in patients undergoing cytotoxic therapy for cancer. At present the only available therapy for thrombocytopenic patients is a platelet transfusion, although several companies are working on platelet stimulators, including interleukins 3, 6, and 11 (various companies) and PixyKine (an IL-3/granulocyte macrophage stimulating factor fusion protein developed by Immunex).