Method of treating SCLC and managing neutropenia

A method of treating metastatic small cell lung cancer (SCLC) in a patient after platinum-based chemotherapy, said method comprising:

• (a) administering a treatment cycle comprising a dose of 3.2 mg/m2 of lurbinectedin by intravenous infusion as sole chemotherapy agent to the patient having, at the time of the administration of the dose of 3.2 mg/m2 of lurbinectedin:
• (i) metastatic SCLC,
• (ii) an absolute neutrophil count of at least 1,500 cells/mm3, and
• (iii) a platelet count of at least 100,000/mm3;
• wherein the patient experienced Grade 4 neutropenia or any grade febrile neutropenia subsequent to the administration of the dose of 3.2 mg/m2 of lurbinectedin and returns within 35 days of the administration of the dose of 3.2 mg/m2 of lurbinectedin to an absolute neutrophil count of at least 1,500 cells/mm3 after experiencing the Grade 4 neutropenia or any grade febrile neutropenia;
• and
• (b) administering by intravenous infusion as sole chemotherapy agent a treatment cycle comprising a dose of 2.6 mg/m2 of lurbinectedin to the patient after the absolute neutrophil count returns to at least 1,500 cells/mm3 and provided the patient has a platelet count of at least 100,000/mm3;
• and wherein one dose of lurbinectedin is administered per treatment cycle, and wherein each treatment cycle is 21 to 35 days.