This study will accrue up to 60 evaluable patients. Cohorts of 3 to 6 patients will receive continuous AZD7451 twice a day orally for 28 days. The MTD will be based on the tolerability observed during the first 4 weeks of treatment only. Up to three patients may be enrolled simultaneously at each dose level. The dose of AZD7451 can be progressively escalated if only 0/3 or 1/6 patients experience a dose limiting toxicity at the prior dose level.