TY - JOUR
T1 - Phase I and pharmacologic trial of cytosine arabinoside with the selective checkpoint 1 inhibitor Sch 900776 in refractory acute leukemias
AU - Karp, Judith E.
AU - Thomas, Brian M.
AU - Greer, Jacqueline M.
AU - Sorge, Christopher
AU - Gore, Steven D.
AU - Pratz, Keith W.
AU - Smith, B. Douglas
AU - Flatten, Karen S.
AU - Peterson, Kevin
AU - Schneider, Paula
AU - Mackey, Karen
AU - Freshwater, Tomoko
AU - Levis, Mark J.
AU - McDevitt, Michael A.
AU - Carraway, Hetty E.
AU - Gladstone, Douglas E.
AU - Showel, Margaret M.
AU - Loechner, Sabine
AU - Parry, David A.
AU - Horowitz, Jo Ann
AU - Isaacs, Randi
AU - Kaufmann, Scott H.
PY - 2012/12/15
Y1 - 2012/12/15
N2 - Purpose: Incorporation of cytarabine into DNA activates checkpoint kinase 1 (Chk1), which stabilizes stalled replication forks, induces S-phase slowing, and diminishes cytarabine cytotoxicity. The selective Chk1 inhibitor SCH 900776 abrogates cytarabine-induced S-phase arrest and enhances cytarabine cytotoxicity in acute leukemia cell lines and leukemic blasts in vitro. To extend these findings to the clinical setting, we have conducted a phase I study of cytarabine and SCH 900776. Experimental Design: Twenty-four adults with relapsed and refractory acute leukemias received timed sequential, continuous infusion cytarabine 2 g/m2 over 72 hours (667 mg/m2/24 hours) beginning on day 1 and again on day 10. SCH 900776 was administered as a 15- to 30-minute infusion on days 2, 3, 11, and 12. The starting dose of SCH 900776 was 10 mg/m2/dose. Results: Dose-limiting toxicities consisting of corrected QT interval prolongation and grade 3 palmarplantar erythrodysesthesia occurred at 140 mg flat dosing (dose level 5, equivalent to 80 mg/m2). Complete remissions occurred in 8 of 24 (33%) patients, with 7 of 8 at 40 mg/m2 or higher. SCH 900776 did not accumulate at any dose level. Marrow blasts obtained pretreatment and during therapy showed increased phosphorylation of H2Ax after SCH 900776 beginning at 40 mg/m2, consistent with unrepaired DNA damage. Conclusions: These data support a randomized phase II trial of cytarabine +/- SCH 900776 at a recommended flat dose of 100 mg (equivalent to 56 mg/m2) for adults with poor-risk leukemias. The trial (SP P05247) was registered at www.clinicaltrials.gov as NCT #00907517.
AB - Purpose: Incorporation of cytarabine into DNA activates checkpoint kinase 1 (Chk1), which stabilizes stalled replication forks, induces S-phase slowing, and diminishes cytarabine cytotoxicity. The selective Chk1 inhibitor SCH 900776 abrogates cytarabine-induced S-phase arrest and enhances cytarabine cytotoxicity in acute leukemia cell lines and leukemic blasts in vitro. To extend these findings to the clinical setting, we have conducted a phase I study of cytarabine and SCH 900776. Experimental Design: Twenty-four adults with relapsed and refractory acute leukemias received timed sequential, continuous infusion cytarabine 2 g/m2 over 72 hours (667 mg/m2/24 hours) beginning on day 1 and again on day 10. SCH 900776 was administered as a 15- to 30-minute infusion on days 2, 3, 11, and 12. The starting dose of SCH 900776 was 10 mg/m2/dose. Results: Dose-limiting toxicities consisting of corrected QT interval prolongation and grade 3 palmarplantar erythrodysesthesia occurred at 140 mg flat dosing (dose level 5, equivalent to 80 mg/m2). Complete remissions occurred in 8 of 24 (33%) patients, with 7 of 8 at 40 mg/m2 or higher. SCH 900776 did not accumulate at any dose level. Marrow blasts obtained pretreatment and during therapy showed increased phosphorylation of H2Ax after SCH 900776 beginning at 40 mg/m2, consistent with unrepaired DNA damage. Conclusions: These data support a randomized phase II trial of cytarabine +/- SCH 900776 at a recommended flat dose of 100 mg (equivalent to 56 mg/m2) for adults with poor-risk leukemias. The trial (SP P05247) was registered at www.clinicaltrials.gov as NCT #00907517.
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U2 - 10.1158/1078-0432.CCR-12-2442
DO - 10.1158/1078-0432.CCR-12-2442
M3 - Article
C2 - 23092873
AN - SCOPUS:84871234067
SN - 1078-0432
VL - 18
SP - 6723
EP - 6731
JO - Clinical Cancer Research
JF - Clinical Cancer Research
IS - 24
ER -