Patients who had previously been treated with docetaxel had a higher incidence of grade 3-4 thrombocytopenia with radium-223 than with placebo ( 31 [ 9 % ] of 347 patients vs five [ 3 % ] of 171 patients ) , whereas the incidence was similar between treatment groups among patients with no previous docetaxel use ( seven [ 3 % ] of 253 patients vs one [ 1 % ] of 130 patients ) .