Scheme of the treatment plan. GO was administered at 6 mg/m2 per dose by intravenous infusion. The second dose was administered after 15 days from the first one. After the second GO dose, patients who tested PCR-negative for PML/RARα in the bone marrow were to receive a third and final dose, whereas patients who tested PCR-positive had to receive additional GO administrations, for a maximum of 6 total doses, until the achievement of PCR negativity.