Vinorelbine-based salvage chemotherapy for therapy-refractory aggressive leukaemias

This study examined the ability of the semi-synthetic vinca alkaloid, Vinorelbine/Navelbine, to cause apoptotic death in freshly obtained primary leukaemia cells from 53 patients with haematological malignancies, including 22 patients with acute lymphoblastic leukaemia (ALL), 24 patients with chronic lymphocytic leukaemia (CLL), three patients with chronic myeloid leukaemia in blast crisis (CML-BC) and four patients with acute myeloid leukaemia (AML). Vinorelbine caused apoptosis in primary leukaemia cells from 42 (79%) of these leukaemia patients. Objective responses, including complete remission (CR) and CR with incomplete haematological recovery, were achieved in 12 of 17 (71%) patients with aggressive and therapy-refractory leukaemias, including five of nine patients with relapsed ALL, three of three patients with CML-BC and four of five patients with rapidly progressive CLL, who were treated with a vinorelbine-based salvage chemotherapy regimen. Drug sensitivity profiling of multidrug-resistant primary cancer cells using apoptosis assays revealed a significant association between Vinorelbine sensitivity in vitro and the likelihood of an objective clinical response to Vinorelbine-based chemotherapy. Vinorelbine-sensitivity testing of primary leukaemia cells might help tailor Vinorelbine-based salvage regimens to those patients who are most likely to respond.     

Bis(4,7-dimethyl-1,10-phenanthroline) sulfatooxovanadium(IV) as a novel apoptosis-inducing anticancer agent.

In a systematic effort to identify a potent anticancer agent, we synthesized 15 oxovanadium(IV) complexes and examined their cytotoxic activity against 14 different human cancer cell lines. The oxovanadium compounds included mono and bis ancillary ligands of 1,10-phenanthroline (phen) [VO(phen), VO(phen)2, VO(Me2-phen), VO (Me2-phen)2, VO(Cl-phen), VO(Cl-phen)2, VO(NO2-phen), VO(NO2-phen)2], 2,2'-bipyridyl (bipy) [VO(bipy), VO(bipy)2, VO(Me2-bipy), VO(Me2-bipy)2], and 2-2'-bipyrimidine(bipym) [VO(bipym) and VO-(bipym)2], linked via nitrogen atoms, and 5'-bromo-2'-hydroxyacetophenone (acph) [VO(acph)2], linked via oxygen donor atom. The mono-chelated [VO(Me2-phen), compound 3] and bis-chelated-phen[VO(Me2-phen)2, compound 4] complexes were the most potent oxovanadium compounds and killed target cancer cells at low micromolar concentrations. Notably, the dimethyl substitution of the phenanthroline rings was essential for the anticancer activity of both compound 4 [VO(Me2-phen)2] and compound 3 [VO(Me2-phen)] because unsubstituted bis-chelated and mono-chelated phen oxovanadium(IV) complexes [VO(phen), compound 1, or VO(phen)2, compound 2] were less active. Addition of a chloro or nitro group to the phen complexes did not significantly improve the cytotoxic activity of the unsubstituted oxovanadium(IV) complexes. Irrespective of the ligands, bis-chelated phenanthroline containing compounds showed better activity than the mono-chelated phenanthroline containing complexes. The marked differences in the cytotoxic activity of oxovanadium(IV) complexes containing different heterocyclic ancillary ligands suggest that the cytotoxic activity of these compounds is determined by the identity of the five-member bidentate ligands, as well as the nature of the substitutents on the heterocyclic aromatic rings. Our results presented herein provide experimental evidence that oxovanadium compounds induce apoptosis in human cancer cells. Oxovanadium compounds, especially the lead compound VO(Me2-phen)2, may be useful in the treatment of cancer.     

In vivo efficacy of B43 (anti-CD19)-pokeweed antiviral protein immunotoxin against human pre-B cell acute lymphoblastic leukemia in mice with severe combined immunodeficiency.

A highly aggressive subclone of the human CALLA+C mu+ pre-B acute lymphoblastic leukemia (ALL) cell line NALM-6 (designated NALM-6-UM1) caused disseminated and fatal leukemia in CB.17 mice with severe combined immunodeficiency (SCID). An intravenous challenge with 1 x 10(6) (NALM-6-UM1 cells caused 15 of 27 (56%) SCID mice to become paraplegic at 31 +/- 2 days (median = 33 days) and 27 of 27 (100%) mice to die of disseminated leukemia at 38 +/- 1 days (median = 39 days). We used this SCID mouse model of aggressive human pre-B ALL to evaluate the in vivo antileukemic efficacy of B43 (anti-CD19)-pokeweed antiviral protein (PAP) immunotoxin. A 3-day treatment with nontoxic doses of B43-PAP markedly reduced the incidence of paraplegia and improved event-free survival (EFS) in SCID mice challenged with 1 x 10(6) NALM-6-UM1 pre-B ALL cells, as reflected by significantly higher cumulative proportions of mice free of paraplegia or alive at 1 to 7 months, as compared with phosphate-buffered saline (PBS) treated control mice. The Kaplan-Meier estimates and standard errors of the probability of developing paraplegia after inoculation of 1 x 10(6) NALM-6-UM1 cells was 64% +/- 10% for PBS-treated mice (median time to paraplegia = 37 days) (N = 27), 18% +/- 8% for mice treated with 15 micrograms B43-PAP (5 micrograms/mouse/d x 3 days) (N = 23) and 5% +/- 5% for mice treated with 30 micrograms B43-PAP (10 micrograms/mouse/d x 3 days) (N = 21). While 27 of 27 PBS-treated control SCID mice died of leukemia at 38 +/- 1 days (range = 24 to 54 days), only 16 of 44 B43-PAP-treated mice developed leukemia at 74 +/- 12 days (range = 30 to 182 days), consistent with greater than or equal to 6 logs kill of clonogenic NALM-6-UM1 cells in 64% of SCID mice. The Kaplan-Meier estimates and standard errors of the probability of long-term EFS after inoculation of 1 x 10(6) NALM-6-UM1 cells were 65% +/- 10% for mice treated with 15 micrograms B43-PAP and 60% +/- 11% for mice treated with 30 micrograms B43-PAP with a median survival time of greater than 7 months for both groups. In contrast, neither unconjugated B43 monoclonal antibody nor the anti-T-cell immunotoxin G17.2 (anti-CD4)-PAP decreased the incidence of paraplegia or improved EFS.(ABSTRACT TRUNCATED AT 400 WORDS)     

Dual targeting of Bruton's tyrosine kinase and Janus kinase 3 with rationally designed inhibitors prevents graft-versus-host disease (GVHD) in a murine allogeneic bone marrow transplantation model

The purpose of the present study was to evaluate the effectiveness of targeting Bruton's tyrosine kinase (BTK) with a specific BTK inhibitor, alpha-cyano-beta-hydroxy-beta-methyl-N-(2,5-dibromophenyl)-propenamide (LFM-A13), for prevention of acute fatal graft-versus-host disease (GVHD) in a murine model of allogeneic bone marrow transplantation (BMT). Vehicle-treated control C57BL/6 mice receiving bone marrow/splenocyte grafts from allogeneic BALB/c donors developed severe multi-organ acute GVHD and died after a median survival time (MST) of 40 d. LFM-A13 treatment (25 mg/kg/d) significantly prolonged the MST of the BMT recipients to 47 d. The probability of survival at 2 months after BMT was 2 +/- 2% for vehicle-treated control mice and 22 +/- 6% for mice treated with LFM-A13 (P = 0.0008). Notably, the combination regimen of LFM-A13 plus the standard anti-GVHD drug methotrexate (MTX) (10 mg/m(2)/d) was more effective than LFM-A13 alone, while the combination regimen of LFM-A13 plus the novel anti-GVHD drug JANEX-1 (60 mg/kg/d), targeting Janus kinase 3, was more effective than LFM-A13, JANEX-1 or MTX alone. More than 70% of recipients receiving this most effective GVHD prophylaxis (LFM-A13 + JANEX-1) remained alive throughout the 80-d observation period with an MST of >80 d. Taken together, these results indicate that targeting BTK with the chemical inhibitor LFM-A13 may attenuate the severity of GVHD, especially when it is combined with other anti-GVHD drugs, such as MTX and JANEX-1.     

Marrow purging in autologous bone marrow transplantation for T-lineage acute lymphoblastic leukemia: efficacy of ex vivo treatment with immunotoxins and 4-hydroperoxycyclophosphamide against fresh leukemic marrow progenitor cells

A lymphoblast progenitor cell assay was used to evaluate the antileukemic efficacy of marrow-purging protocols that employed intact ricin immunotoxins (IT) and 4-hydroperoxycyclophosphamide (4-HC) against clonogenic primary T-lineage marrow blasts freshly obtained from 12 T-lineage acute lymphoblastic leukemia (ALL) patients. Residual T-lineage blast colonies were observed after treatment with 1 micrograms/mL T101 (anti-CD5)-Ricin (R) + G3.7 (anti-CD7)-R in eight of 12 cases and after 100 micrograms/mL 4-HC in six of nine cases. By comparison, a combination of IT and 4-HC proved very effective against T-lineage leukemic progenitor cells, and no residual blast colonies were observed in any of the eight cases studied. We conclude that future trials should consider combined treatment protocols such as IT + 4-HC for more effective purging of autologous marrow grafts.     

Short-Term (13-week) toxicity study of 5-bromo-6-methoxy-5,6-dihydro-3'-azidothymidine-5'-(p-bromophenyl) methoxyalaninyl phosphate (WHI-07), a novel anti-HIV and contraceptive agent, in B6C3F1 mice.

The zidovudine derivative, WHI-07 (5-bromo-6-methoxy-5,6-dihydro-3'-azidothymidine-5'-(p-bromophenyl) methoxyalaninyl phosphate), is a dual-function spermicidal agent with potent anti-HIV activity. In this study, groups of 20 female B6C3F1 mice were exposed intravaginally to a gel microemulsion containing 0, 0.5, 1.0, or 2.0% WHI-07, 5 days per week for 13 consecutive weeks. On a molar basis, these concentrations of WHI-07 are 1400- to 5700-times higher than its spermicidal EC(50) and 1.4 x 10(6) to 5.7 x 10(6) times higher than its in vitro anti-HIV IC(50). After 13 weeks of intravaginal treatment, mice were evaluated for toxicity. The endpoints that were used for evaluation included survival, body weight, hematologic and clinical chemistry profiles, absolute and relative organ weights, and histopathology. No effects related to WHI-07 treatments were observed on survival, mean body weight, and mean body-weight gain. Repeated intravaginal exposure of mice to WHI-07 for 13 weeks had no toxicologically significant effect on organ weights, and did not cause any adverse changes in hematology parameters or blood chemistry profiles. Extensive histopathologic examination of tissues showed no lesions of pathologic significance. Thus, intravaginal application of WHI-07, for up to 13 weeks, does not cause systemic toxicity.