A checkpoint in the cell cycle progression as a therapeutic target to inhibit HIV replication.

Human immunodeficiency virus (HIV) expression is boosted after T lymphocyte stimulation. It is not known, however, in which phase(s) of the cell cycle HIV is maximally expressed. We demonstrate here that cell activation induces limited HIV expression and that progression to cell proliferation is required for optimal HIV replication. We also show that the G1/S cell cycle transition is a critical checkpoint in this process and that limiting progression at this step with antiproliferative drugs suppresses HIV replication. These results identify a specific phase of the cell cycle progression that is critical for HIV expression and suggest a new discrete target for anti-HIV treatment.

A combination of dexamethasone, cyclophosphamide, etoposide, and cisplatin is less toxic and more effective than high-dose cyclophosphamide for peripheral stem cell mobilization in multiple myeloma.

BACKGROUND AND OBJECTIVES: The purpose of this study was to compare the efficacy and toxicity of two regimens for peripheral blood stem cell (PBSC) mobilization in multiple myeloma (MM) patients. DESIGN AND METHODS: From 1995 to 2001, 116 patients were enrolled in two high-dose programs including autologous transplantation, adopting two mobilizing regimens: 61 patients were mobilized with high-dose cyclophosphamide (HD-Cy) at 4 g/m2 (group I), and 55 patients with DCEP (dexamethasone, cyclophosphamide, etoposide, and cisplatin) (group II), both followed by granulocyte colony-stimulating factor (G-CSF 5 mg/Kg/day) started 48 hours after chemotherapy. RESULTS: The median number of CD34+ cells harvested was similar in the two groups (5.9 vs 5.82x106 cells/kg). The target of at least 4x106 cells/kg was reached in a higher percentage of patients in the DCEP group (75 vs 59%) (p=0.05). The proportion of poor mobilizers (<2x106 CD34+ cells/kg) was 21% with HD-Cy and 13% with DCEP (P=NS). In group I, 10 patients (16%) required packed red cell transfusions, 5 patients (8%) platelet support, and the majority of patients (87%) had a neutrophil count below 500/mL, whereas none did so in group II (p=0.0009, p=0.01, p=0.0009, respectively). Neutropenia-related fever occurred in 18% of patients in group I versus 0% in group II (p=0.0005). WHO grade >II extra-hematologic toxicities (microhematuria, cystitis, infections) were seen in 8 patients (13%) of group I vs 0 in group II (p=0.007). INTERPRETATION AND CONCLUSIONS: DCEP is a better tolerated and more effective regimen than HD-Cy for peripheral stem cell mobilization in MM patients assigned to high-dose therapy programs.