The interaction of acute myeloid leukemia (AML) blasts with the leukemic microenvironment is postulated to be an important mediator of resistance to chemotherapy and disease relapse. We hypothesized that inhibition of the CXCR4/CXCL12 axis by the small molecule inhibitor, plerixafor, would disrupt the interaction of leukemic blasts with the environment and increase the sensitivity of AML blasts to chemotherapy. In this phase 1/2 study, 52 patients with relapsed or refractory AML were treated with plerixafor in combination with mitoxantrone, etoposide, and cytarabine. In phase 1, plerixafor was escalated to a maximum of 0.24 mg/kg/d without any dose-limiting toxicities. In phase 2, 46 patients were treated with plerixafor 0.24 mg/kg/d in combination with chemotherapy with an overall complete remission and complete remission with incomplete blood count recovery rate (CR ؉ CRi) of 46%. Correlative studies demonstrated a 2-fold mobilization in leukemic blasts into the peripheral circulation. No evidence of symptomatic hyperleukocytosis or delayed count recovery was observed with the addition of plerixafor. We conclude that the addition of plerixafor to cytotoxic chemotherapy is feasible in AML, and results in encouraging rates of remission with correlative studies demonstrating in vivo evidence of disruption of the CXCR4/CXCL12 axis.

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Objective:Thrombotic thrombocytopenic purpura (TTP) is a life-threatening disease. The primary aim was overall response rate (ORR) assessment in the treated patientsMethods:This retrospective study included 24 patients treated during 2006-2015. TTP patients with microangiopathic hemolysis (MAHA) and thrombocytopenia were included. We analyzed clinical features, laboratory characteristics and treatment outcomes of 24 TTP patients treated at our tertiary care center (KFMC).Results:Twenty-four TTP patients (18 females; 6 males) had a mean age of 33.5±13.9 years; 22(91%) had neurologic features, 7(29%) fever, 10(42%) renal impairment; 4(20.83%) cardiac manifestations; 22(91.7%) had triad with additional neurologic abnormalities; only 2(8.2%) had pentad of TTP. Majority (54.16%) had idiopathic TTP. All patients received therapeutic plasma exchange (TPE); 23(95.8%) received adjunctive corticosteroids and 13(54.2%) received rituximab either due to refractoriness to TPE on ~day7, or earlier. Twenty-one out of 24 (87.5%) achieved complete remission (CR) without any subsequent relapse. At 22 months (median, range 1-113), 20 patients (83.3%) are alive at the time of report. Three patients died during acute episode because of sever disease or delayed treatment and one died in CR.Conclusion:TPE, steroids and or rituximab was very effective in preventing high risk of mortality and achieving durable CR in 87.5% of patients. More awareness is needed for early diagnosis and early referral to centers with appropriate tertiary care facilities..

Allogeneic stem cell transplantation (allo-SCT) is a potentially curative treatment for high-risk acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS). For patients with relapsed disease after transplantation, intensive chemotherapy followed by donor lymphocyte infusion (DLI) or a second allo-SCT may result in a durable response in some patients. High-intensity chemotherapy and less aggressive therapy with hypomethylating agents (HAs) with and without DLI are often used for relapse after allo-SCT. Here we compared the treatment outcomes of intensive chemotherapy with that of HAs in relapsed AML and MDS after allo-SCT. Patients who had received a second SCT within 90 days of the relapse date were excluded. The primary endpoints were overall response rate (ORR) and overall survival (OS). Secondary endpoints were complete remission (CR) rate and progression-free survival (PFS). One hundred patients were included: 73 patients received chemotherapy and 27 patients received an HA. Fifty-six percent of patients in the chemotherapy group and 33% of patients in the HA group received at least 1 DLI after treatment. Treatment with chemotherapy resulted in a higher ORR (51% versus 19%, P = .004) and a higher CR rate (40% versus 7%, P = .002). The median OS (6 versus 3.9 months, P = .01) and PFS (4.9 versus 3.8 months, P = .02) were longer in the chemotherapy group. Similar benefit of chemotherapy over HAs was maintained in all treatment outcomes after controlling for the use of DLI. The use of chemotherapy followed by DLI offered the greatest benefit (ORR, 68%; CR, 59%, 1-year OS, 44%; and median OS, 9.8 months). In conclusion, in our hands, with limited numbers, the use of more conventional salvage chemotherapy, with DLI when possible, for the treatment of relapsed AML and MDS after allo-SCT is associated with better outcomes than nonchemotherapy (HA) options.