cells appear to be sensitive to paclitaxel and 66.7% of paclitaxel-resistant cells to cisplatin. The mechanism for this activity is unknown. Paclitaxel-based chemotherapy showed modest activity in SCLC patients refractory to both etoposide- and camptothecin-based chemotherapy. The newer agent lurbinectedin is active in relapsed SCLC and was approved for medical use in the United States in June 2020. Immunotherapy In 2018, the FDA approved two immunotherapies for small cell lung cancer: 1. Nivolumab (Opdivo), and 2. Atezolizumab (Tecentriq) Funding controversy Tecentriq treatment costs on average $13,200 per month, depending on the dosage schedule. Despite updated data showing 30% more people with extensive stage small cell lung cancer are alive at 24 months compared to those who received chemotherapy alone, Canadian regulator had rejected to fund Tecentriq for extensive stage small-cell lung cancer "as too costly" followed by United Kingdom also citing "drug’s cost-effectiveness." Radiation therapy Chest radiation helps SCLC patients live longer by killing cancer cells and helping prevention of cancer recurrence. Another type of radiation, prophylactic cranial radiation, prevents central nervous system recurrence and can improve survival in patients with good performance status who have had a complete response or a very good partial response to chemoradiation in LD or chemotherapy in ED. In case of relapse If small cell lung cancer comes back after treatment, the following combination of drugs may be used as a salvage therapy: Cyclophosphamide (Cytoxan, Procytox), Doxorubicin (Adriamycin) and Vincristine (Oncovin) Paclitaxel (Taxol) Irinotecan (Camptosar) Current guidelines recommend that patients who relapse > 6 months from initial therapy should be retreated with the original chemotherapy regimen. For patients who relapse in < 6 months, single-agent chemotherapy either topotecan second-line therapy, or paclitaxel can be used. Novel agents Several newer agents, including temozolomide and bendamustine, have activity in relapsed SCLC. Of note, temozolomide yielded a response rate of 38% for brain metastases due to SCLC. In a clinical trial of 50 patients, combination of olaparib and temozolomide in relapsed small-cell lung cancer yielded an overall response rate of 41.7%, median progression-free survival 4.2 months, and overall survival was 8.5 months. Lurbinectedin is the most promising new agent that substantially increased overall survival rate in relapsed small cell lung cancer among sensitive disease patients. As a single agent, lurbinectedin demonstrated following clinical results in refractory small cell lung cancer trial: Overall survival rate of 15.2 months for sensitive disease (chemotherapy-free interval of ≥ 90 days) with