TY - JOUR
T1 - A phase 1 clinical-laboratory study of clofarabine followed by cyclophosphamide for adults with refractory acute leukemias
AU - Karp, Judith E.
AU - Ricklis, Rebecca M.
AU - Balakrishnan, Kumudha
AU - Briel, Janet
AU - Greer, Jacqueline
AU - Gore, Steven D.
AU - Smith, B. Douglas
AU - McDevitt, Michael A.
AU - Carraway, Hetty
AU - Levis, Mark J.
AU - Gandhi, Varsha
PY - 2007/9/15
Y1 - 2007/9/15
N2 - Clofarabine has shown impressive response rates in patients with acute leukemias. In vitro investigations with clofarabine in combination with cyclophosphamide in primary cells have demonstrated synergistic cytotoxicity and inhibition of DNA repair. Based on these clinical and laboratory observations, we designed a mechanism-based combination protocol with clofarabine and cyclophosphamide for patients with relapsed acute leukemias. Eighteen patients were treated with cyclophosphamide (200 mg/m2) alone on day 0 and with clofarabine plus cyclophosphamide on day 1. Clinical responses, toxicity, DNA damage measured as H2AX phosphorylation, and accumulation of clofarabine triphosphate (TP) were analyzed. At dose level 1 (20 mg/m2 clofarabine + cyclophosphamide, 6 patients) and dose level 0 (10 mg/m 2 clofarabine + cyclophosphamide, 12 patients) overall response rates were 50% and 30%, respectively, with responses in 4 (67%) of 6 patients with refractory acute lymphoblastic leukemia. Dose-limiting toxicity occurred at dose level 1 with prolonged marrow aplasia. Four (22%) patients died from prolonged aplasia (1), fungal pneumonia (1), or multiorgan failure (2). In 12 of 13 patient samples, increased DNA damage (γH2AX) was observed with clofarabine and cyclophosphamide compared with cyclophosphamide alone. In conclusion, pharmacodynamic end points along with clinical results suggest usefulness of this combination strategy, whereas toxicity data suggest reduction in chemotherapeutic intensity. This clinical trial is registered with the National Cancer Institute's PDQ at www.clinicaltrials.gov as no. JHOC-J0561.
AB - Clofarabine has shown impressive response rates in patients with acute leukemias. In vitro investigations with clofarabine in combination with cyclophosphamide in primary cells have demonstrated synergistic cytotoxicity and inhibition of DNA repair. Based on these clinical and laboratory observations, we designed a mechanism-based combination protocol with clofarabine and cyclophosphamide for patients with relapsed acute leukemias. Eighteen patients were treated with cyclophosphamide (200 mg/m2) alone on day 0 and with clofarabine plus cyclophosphamide on day 1. Clinical responses, toxicity, DNA damage measured as H2AX phosphorylation, and accumulation of clofarabine triphosphate (TP) were analyzed. At dose level 1 (20 mg/m2 clofarabine + cyclophosphamide, 6 patients) and dose level 0 (10 mg/m 2 clofarabine + cyclophosphamide, 12 patients) overall response rates were 50% and 30%, respectively, with responses in 4 (67%) of 6 patients with refractory acute lymphoblastic leukemia. Dose-limiting toxicity occurred at dose level 1 with prolonged marrow aplasia. Four (22%) patients died from prolonged aplasia (1), fungal pneumonia (1), or multiorgan failure (2). In 12 of 13 patient samples, increased DNA damage (γH2AX) was observed with clofarabine and cyclophosphamide compared with cyclophosphamide alone. In conclusion, pharmacodynamic end points along with clinical results suggest usefulness of this combination strategy, whereas toxicity data suggest reduction in chemotherapeutic intensity. This clinical trial is registered with the National Cancer Institute's PDQ at www.clinicaltrials.gov as no. JHOC-J0561.
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U2 - 10.1182/blood-2007-03-081364
DO - 10.1182/blood-2007-03-081364
M3 - Article
C2 - 17562873
AN - SCOPUS:34548851697
SN - 0006-4971
VL - 110
SP - 1762
EP - 1769
JO - Blood
JF - Blood
IS - 6
ER -