The R-isomer of
roscovitine is currently in phase II under the auspices of
Cyclacel with reports of clinical trials in Europe. Although
some beneficial effects are observed with signal transduction
inhibitors (STIs) alone, complete or partial responses tend
only to be demonstrated when sequential treatments of STI/
cytotoxin are used, so also with R-roscovitine, sequential
treatment with cytotoxins is being used and/or considered