(ChemotherapyAdvisor) – Clofarabine plus cytarabine (Clo+Ara-C) significantly prolongs event-free survival (EFS), according to an international team of researchers. This conclusion is based on a study entitled “Clofarabine plus Cytarabine Compared with Cytarabine Alone in Older Patients with Relapsed or Refractory Acute Myelogenous Leukemia: Results From the CLASSIC I Trial,” which was published in the July 10 issue of the Journal of Clinical Oncology.

In this study, the investigators aimed to compare the effectiveness of administering clofarabine plus cytarabine (Clo+Ara-C arm) with cytarabine (Ara-C arm) to treat patients ≥55 years old who been previously diagnosed with refractory or relapsed acute myelogenous leukemia (AML). To meet this aim, patients (N=82) were randomized to receive clofarabine (Clo) 40mg/m2 or a placebo followed by Ara-C 1g/m2 for 5 consecutive days, until they reached pre-selected end points [primary: overall survival (OS); secondary: event-free survival (EFS), 4-month EFS, overall remission rate (ORR), disease-free survival (DFS), duration of remission (DOR), and safety.]

The investigators reported the following results. The median OS was 6.6 months in the Clo+Ara-C arm and 6.3 months in the Ara-C arm (hazard ratio [HR], 1.00; 95% CI, 0.78 to 1.28; P=1.00). The ORR was 46.9% in the Clo+Ara-C arm (35.2% CR) vs 22.9% in the Ara-C arm (17.8% CR; P<.01). EFS (HR: 0.63; 95% CI, 0.49 to 0.80; P<.01) and 4-month EFS (37.7% vs 16.6%; P<.01) favored the Clo+Ara-C arm compared with Ara-C arm, respectively. DFS and DOR were similar in both arms. In the Clo+Ara-C and Ara-C arms, the most common grade 3/4 toxicities were febrile neutropenia (47% vs 35%, respectively), hypokalemia (18% vs 11%, respectively), thrombocytopenia (16% vs 17%, respectively), pneumonia (14% vs 10%, respectively), anemia (13% vs 0%, respectively), neutropenia (11% vs 9%, respectively), increased AST (11% vs 2%, respectively), and increased ALT (10% vs 3%, respectively).

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The investigators concluded: “Although the primary end point of OS did not differ between arms, Clo+Ara-C significantly improved response rates and EFS.”