In particular, we conclude that treatment with prednisone should not start in the first 4 weeks (too early) and not in week 7 (very late); schedules S5, and possibly S6, are the optimal ones; more generally, treatment with prednisone should start as soon as tumor volume, under the effect of CTLA-4 inhibitor alone, begins to decrease. The gene discussed is CTLA4; the disease is neoplasm.