cyclophosphamide + fludarabine + clofarabine + etoposide + interleukin-2

This combination therapy involves cyclophosphamide (an alkylating agent), fludarabine (a purine nucleoside analog), clofarabine (a second-generation purine nucleoside analog), etoposide (a topoisomerase II inhibitor), and interleukin-2 (a cytokine). Based on the provided search results, the exact combination of all five agents is not specifically described as a single standardized regimen. However, the individual components are used in various sub-combinations for treating refractory or relapsed acute leukemias, conditioning before cellular therapies (like CAR-T), and as bridge-to-transplant approaches. * Cyclophosphamide and fludarabine are commonly used together for lymphodepletion before CAR-T cell therapy. * Clofarabine, etoposide, and cyclophosphamide (CloEC) have been studied as a bridge-to-transplant regimen in pediatric refractory acute leukemia. * Clofarabine has been used with cyclophosphamide before CAR-T cell infusion. * Interleukin-2 is mentioned in combination with fludarabine and cyclophosphamide for lymphodepletion in the context of certain cell therapies. The efficacy and safety data presented in the results relate to these sub-combinations, showing variable response rates and significant toxicity, particularly immunosuppression and infection risk.