Recent studies evaluating cabazitaxel in pretreated patients with non-small-cell lung cancer and head and neck carcinoma, have also reported similar rates of severe (grade 3–4) neutropenia, despite primary prophylaxis with G-CSF.16,17 However, the rates of grade 3–4 neutropenia were considerably lower compared with the reported incidence in the pivotal study in prostate cancer.9 Nevertheless, in the pivotal study neutropenia was measured at the nadir in all patients and prophylactic G-CSF was not allowed at cycle 1. The gene discussed is CSF3; the disease is neutropenia.