R306465 will be administered in a continuous regimen for 21 days followed by a 1-week rest period, which constitutes a 28-day treatment cycle. The dose of R306465 will start low and will be increased during the study in groups of 3 to 6 patients. If a group of patients does not have severe side effects, the next group of patients will get a higher dose. The dose will increase until some patients have severe side effects. The dose will then be decreased to a dose level where severe side effects are observed in less than 1/3 of patients. The amount of R306465 in the blood will be measured and the effect on the disease will be evaluated in all patients.