Subcutaneous omacetaxine mepesuccinate in chronic myeloid leukemia (CML) patients resistant or intolerant to two or more tyrosine kinase inhibitors (TKIs): Data from an ongoing phase II trial

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Background: Omacetaxine (OM), a first-in-class cetaxine, shows clinical activity against Ph+ CML with a mechanism of action independent to tyrosine kinase inhibition. Patients (Pts) who have failed multiple TKIs may benefit from an alternative therapy for CML. Methods: Pts include adult CML following resistance or intolerance to at least 2 TKIs. T315I+ Pts are enrolled in a separate trial. Pts receive OM induction at 1.25 mg/m2 subcutaneous (SC) BID for 14 days every 28 days followed by maintenance at 1.25 mg/m2 SC BID for 7 days every 28 days (maintenance after at least one induction cycle and achievement of hematologic response). Results: 60 pts (30 chronic phase [CP], 14 accelerated phase [AP], and 16 blast phase [BP] have been enrolled with 51% having failed at least 3 prior TKIs. Median age: 58 yrs; 50% male. Median disease duration: 74 months. At baseline, 38.5% of pts had Bcr-Abl mutations including 9.6% with compound mutations. The most frequently observed mutations were F317L (11.5%) and V299L (5.8%). OM is well tolerated with transient myelosuppression as the primary toxicity. Grade 3/4 non-hematologic events are rare with pyrexia occurring in 4.3% of patients. Efficacy data are available for 30 Pts: Conclusions: Omacetaxine in multi-TKI resistant or intolerant CML is well tolerated and has achieved hematologic and cytogenetic responses in these heavily pre-treated Pts.

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Factors influencing varicella zoster virus infection after allogeneic peripheral blood stem cell transplantation: low-dose acyclovir prophylaxis and pre-transplant diagnosis of lymphoproliferative disorders

Varicella zoster virus (VZV) infection is one of the frequent opportunistic infections after allogeneic bone marrow transplantation, with a high incidence of 30-50%. However, no data have been reported on VZV infection after allogeneic peripheral blood stem cell transplantation (PBSCT).

PATIENTS AND METHODS

We report a retrospective analysis of VZV infection in 192 allogeneic PBSCT recipients. Twenty-seven patients (14%) received long-term prophylaxis of low-dose acyclovir (200 mg twice daily orally > or =3 months) for recurrent oral (n=21) or genital herpes simplex virus infection (n=5) or for a previous history of recurrent VZV infection (n=1).

RESULTS

Forty-two patients (22%) developed VZV infections: localized (n=37) and disseminated infection (n=5). The incidence of VZV infection at 1 and 3 years was 19.3+/-3.3% and 36.8+/-5.2%, respectively. Complications included post-herpetic neuralgia (n=18, 43%), secondary bacterial infections (n=3), and intracranial hemorrhage (n=1) with 2 deaths. A higher risk factor for VZV infection was pre-transplant diagnosis of a lymphoproliferative disorder (LPD): chronic lymphocytic leukemia, Hodgkin's disease, or non-Hodgkin's lymphoma (P=0.021, 52.5% in LPD vs. 32.6% in non-LPD group). The use of low-dose acyclovir prophylaxis (P=0.043, 14.7% in acyclovir vs. 41.6% in nonacyclovir group) was found to be protective. Although no VZV infection episodes were noted during the period of acyclovir prophylaxis, 3 episodes of VZV infection were noted after acyclovir cessation.

CONCLUSION

The incidence of VZV infection after PBSCT was high at 36.8%, with patients transplanted for LPDs at higher risk. The long-term use of low-dose acyclovir may be protective for VZV infection, although it does not completely prevent rebound of late VZV infection.

International, open-label, noncomparative, clinical trial of micafungin alone and in combination for treatment of newly diagnosed and refractory candidemia

Candida spp. are the fourth leading cause of bloodstream infections, and non-albicans species are increasing in importance. Micafungin is a new echinocandin antifungal agent with excellent in vitro activity against Candida spp. Pediatric, neonatal, and adult patients with new or refractory candidemia were enrolled into this open-label, noncomparative, international study. The initial dose of micafungin was 50 mg/d (1 mg/kg for patients <40 kg) for infections due to C. albicans and 100 mg/d (2 mg/kg for patients <40 kg) for infections due to other species. Dose escalation was allowed. Maximum length of therapy was 42 days. A total of 126 patients were evaluable (received at least five doses of micafungin). Success (complete or partial response) was seen in 83.3% patients overall. Success rates for treatment of infections caused by the most common Candida spp. were as follows: C. albicans 85.1%, C. glabrata 93.8%, C. parapsilosis 86.4%, and C. tropicalis 83.3%. Serious adverse events related to micafungin were uncommon. Micafungin shows promise as a safe and effective agent for the treatment of newly diagnosed and refractory cases of candidemia. Large-scale, randomized, controlled trials are warranted.

Is it appropriate to offer allogeneic hematopoietic stem cell transplantation to patients with primary refractory acute myeloid leukemia?

Although continued advances have been made in the treatment of acute myeloid leukemia (AML), approximately 20-30% of patients will never achieve a remission. For these patients with primary refractory AML, the only curative option remains an allogeneic stem cell transplant. Allogeneic transplantation provides the ability to administer myeloablative doses of chemotherapy or chemoradiotherapy, as well as the advantage of a possible graft-versus-leukemia effect. Difficulty in interpreting the literature is due to selection bias, in particular, the varying definitions of primary refractory disease with respect to the morphological criteria and the number of induction regimen required before being defined as being refractory. Regardless, it is a procedure with high treatment-related mortality and risk of relapse. Most studies demonstrate an event-free survival of 10-20% at 5 years. Predictive factors of outcome include blast cell count in the marrow, karyotype, the number of prior regimen, age, performance status and availability of a related donor. These prognostic factors should be considered prior to offering allogeneic transplantation for primary refractory AML. Those patients with many favorable prognostic factors and an HLA-matched related donor available would be the best candidate for the procedure. Those with many poor prognostic factors and only an unrelated donor available may be better served by being offered palliation or being enrolled in investigational studies.

Myeloablative allografting for chronic lymphocytic leukemia: evidence for a potent graft-versus-leukemia effect associated with graft-versus-host disease

In all, 30 patients with CLL proceeded to myeloablative allogeneic BMT using related (n=20, 67%) or unrelated (n=10) donors, at the Princess Margaret Hospital (Toronto) (n=20) or the Leukemia/BMT Program of BC (Vancouver) (n=10), from 1989 to 2001. Median (range) interval from diagnosis to BMT was 4.8 (0.3-13) years, median number of prior therapies was three and median age 48 years. The preparative regimen included total body irradiation in 15 (50%). In all, 14 of 30 patients (47%) are alive, with median (range) follow up of 4.3 (2.4-10.5) years. All are in complete remission, two following therapy for post-BMT progression. Actuarial overall (OS) and event-free survival (EFS) at 5 years is 39% (OS 48% for related donor and 20% for unrelated donor BMT); cumulative incidence of nonrelapse mortality (NRM) and relapse is 47 and 19%, respectively. Both acute (RR=0.008, P=0.01) and chronic (RR=0.006, P=0.02) Graft-versus-host disease (GVHD) were associated with markedly decreased risk of relapse. Patients receiving grafts from unrelated donors had increased NRM (RR=3.6, P=0.02) and decreased OS (RR of death=3.4, P=0.002). Allogeneic BMT has resulted in long-term EFS in approximately 40% of patients with CLL. There is evidence for a strong graft-versus-leukemia effect associated with acute and chronic GVHD, resulting in near complete protection from relapse.

T-cell large granular lymphocytic leukemia of donor origin occurring after allogeneic bone marrow transplantation for B-cell lymphoproliferative disorders

T-cell lymphoproliferative disorders are uncommon occurrences after bone marrow transplantation (BMT). We describe 2 patients in whom a monoclonal T-cell large granular lymphocytosis (T-LGL) developed after allogeneic BMT for B-cell lymphoproliferative disorders. Both patients showed a persistent expansion of CD3+, CD8+, and CD57+ large granular lymphocytes of donor origin with clonally rearranged T-cell receptor gamma genes and no evidence of Epstein-Barr virus-related infection. The manifestations were consistent with T-LGL leukemia as defined by the World Health Organization criteria. In both patients, graft-vs-host disease developed, and 1 had recurrent episodes of cytomegalovirus viremia. The other patient had received a graft from a hepatitis C antibody-positive donor without developing any signs of hepatitis C infection. Both patients remain in complete remission from their B-cell lymphoproliferative disorders and do not have symptoms related to T-LGL leukemia. These data show that T-LGL leukemia should be included as one of the types of posttransplantation lymphoproliferative disorders that can occur after allogeneic BMT for B-cell neoplasms.

Chronic lymphocytic leukemia in the course of chronic myelocytic leukemia: evidence of independent clonal origin as shown by interphase fluorescence in situ hybridization and fluorescence-activated cell sorting

We report the case of a 57-year-old man who developed chronic lymphocytic leukemia (CLL) several months after the initial diagnosis of Philadelphia (Ph) chromosome-positive (Ph(+)) chronic myelocytic leukemia. CLL cells were purified by using fluorescence-activated cell sorting and further analyzed using interphase fluorescence in situ hybridization with probes to detect the BCR/ABL fusion gene. We provide evidence that the CLL cells arose in a Ph(-) clone.

An evaluation of the donor experience in the canadian multicenter randomized trial of bone marrow versus peripheral blood allografting

We compared the donation of bone marrow (BM) versus recombinant human granulocyte colony-stimulating factor-mobilized peripheral blood progenitor cells (PBPC) in HLA-matched sibling donors. Donors randomized to donate BM or PBPC completed questionnaires (Profile of Mood States [POMS] and Short-Form 36 Health Survey) assessing peridonation health-related quality of life (QoL), donation experience, and acceptability of donation before and 1 week and 4 weeks after donation. Between January 1996 and March 1999, 184 patients and their donors were randomized. Predonation and postdonation data were available on 52 (56%) and 35 (38%) of the BM and PBPC donors, respectively. The median donor age was 45 years, and 44% were female. The median time (range) to return to full activity for the BM and PBPC donors was 4 days (1-21 days) and 2 days (0-21 days), respectively (P = .01). One week after donation, BM donors reported more fatigue and less energy than the PBPC donors. BM donors' POMS total mood disturbance scores were worse 1 week after versus before donation, whereas the PBPC donors' scores did not change. POMS subscores indicated more fatigue and less energy in the BM versus PBPC donors. Anxiety improved in both groups, but more in PBPC donors. Four weeks after donation, the Short-Form 36 Health Survey indicated persistent moderate negative effects on QoL with BM donation versus small effects with PBPC donation. BM donation was associated with more physical morbidity and negative effects on QoL up to 1 month after donation than was PBPC donation. Despite this, most donors would donate again. Further work is needed to decrease donor anxiety and symptoms. If both BM and PBPC donation are feasible, then the graft source should be dictated by the predicted patient outcome as determined from the results of randomized trials.

Response to imatinib in patients who relapse after allogeneic stem cell transplantation for chronic myeloid leukemia

We studied 128 patients with chronic myeloid leukemia (CML) relapsing after allogeneic stem cell transplantation (SCT). Disease at the time of treatment with Imatinib was in chronic phase (CP) in 51 patients, accelerated phase (AP) in 31 and blastic crisis (BC) in 46. Of the 51 patients in CP, 14 were in cytogenetic and two in molecular relapses. The median interval between relapse and Imatinib therapy was 5 months (0-65). A total of 50 patients had failed treatment with donor lymphocyte infusions prior to Imatinib. The overall hemato-logical response rate was 84% (98% for patients relapsing in CP). The complete cytogenetic response (CCR) was 58% for patients in CP, 48% for AP and 22% for patients in BC. Complete molecular responses were obtained in 25 patients (26%), of whom 21 were in CP or AP. With a median follow-up of 9 months, the estimated 2-year survival for CP, AP and BC patients was 100, 86 and 12%, respectively. Out of 79 evaluable patients, 45 (57%) achieved full donor and 11 (14%) mixed chimerism after Imatinib. We conclude that Imatinib has significant activity against CML in relapse after allogeneic SCT. Durable cytogenetic and molecular remissions are obtainable in patients in CP.

Stem cell transplantation for myelofibrosis: a report from two Canadian centers

We describe the course of 25 patients with myelofibrosis (MF) due to agnogenic myeloid metaplasia (n=19) or essential thrombocytosis (n=6) who underwent allogeneic stem cell transplantation (SCT) at one of two Canadian centers. The median age at transplantation was 48.7 (IQR 45.9-50.4) years and transplantation was carried out at a median of 10.7 (IQR 5.67-26.5) months after diagnosis. Granulocyte engraftment (absolute neutrophil count >0.5 x 109/l) occurred at a median of 20 days after transplantation for splenectomized patients, compared with 27.5 days for nonsplenectomized individuals (P=0.03). Increased risk of grade II-IV acute graft-versus-host disease (P=0.04) was noted in patients transplanted after splenectomy. Patients with MF received 0.264+/-0.189 U of packed red blood cells per day over the first 180 days after transplantation, and remained dependent on red blood cell transfusions for a median of 123 (IQR 48-205) days. Complete remission of MF was documented in 33% of evaluable patients. The 1 year cumulative nonrelapse mortality was 48.3%. Median survival for this group of patients was 393 (IQR 109-1014+) days, with a projected 2-year overall survival of 41%. We conclude that allogeneic SCT offers a reasonable chance for prolonged survival in patients with advanced MF, but this occurs at the cost of considerable toxicity and nonrelapse mortality.

Why aren't we performing more allografts for aggressive non-Hodgkin's lymphoma?

Allogeneic stem cell transplantation has an under-appreciated role in the management of intermediate-grade non-Hodgkin's lymphoma. It provides several advantages over autologous stem cell transplantation including provision of a lymphoma-free graft, reduced rates of secondary myelodysplastic syndrome and leukemia, and a potentially curative graft-versus-lymphoma effect. When applied to chemosensitive patients, the lower relapse rates and reasonable long-term outcomes make allogeneic transplantation a promising therapy to pursue. Patient populations, such as those with bone marrow involvement or very high-risk disease, can be identified as having suboptimal outcomes after autotransplantation and may benefit from such an approach. While the exact role of allogeneic stem cell transplantation remains to be determined, broad recommendations can be suggested for the management of patients with intermediate-grade lymphoma. New approaches to allogeneic transplantation, including the use of matched-unrelated donors and reduced-intensity conditioning regimens, may expand the applicability of this potentially curative modality.

The effects of long-term cadmium exposure on the growth and survival of juvenile bull trout (Salvelinus confluentus)

Bull trout (Salvelinus confluentus) have been listed recently as threatened in the United States under the federal Endangered Species Act. This species currently resides, or historically resided, in several waterways that either are impacted or are under threat of impact from metals mining activities. We conducted a 55-day sub-chronic (i.e. sublethal) cadmium (Cd) exposure in water at 30 mg l(-1) (as CaCO(3)) hardness, pH 7.5, and 8 degrees C. Exposures were conducted using six replicate exposure tanks for each of the six treatments (five Cd concentrations and one control). Measured Cd concentrations were <0.013 (control), 0.052, 0.089, 0.197, 0.383, and 0.786 microg Cd l(-1). Exposure to 0.786 microg Cd l(-1) caused increased mortality (37%) and reduced growth (28% reduction in weight change) in fish exposed for 55 days. All Cd exposure concentrations caused significant whole body accumulation of Cd compared with controls. Our results indicate that even though fish are significantly accumulating Cd in each non-control treatment, growth reductions in bull trout occurred only at Cd concentrations that also caused significant mortality. The Cd concentration that reduced growth and survival in this long-term exposure (0.786 microg Cd l(-1)) is greater than the recently-revised US federal aquatic life criteria (ALC) value for the corresponding hardness concentration (ALC=0.62 microg Cd l(-1) for acute effects and 0.11 microg Cd l(-1) for chronic effects).

Relationship between exposure duration, tissue residues, growth, and mortality in rainbow trout (Oncorhynchus mykiss) juveniles sub-chronically exposed to copper

We conducted a 56-day sub-chronic test on the effects of Cu on rainbow trout (Oncorhynchus mykiss) fry at a nominal water hardness of 100 mg l(-1) (as CaCO(3)). Response measures were growth, whole body Cu concentrations, and mortality. Significant mortality was observed in fish exposed to 54.1 microg Cu l(-1) (47.8%) and 35.7 microg Cu l(-1) (11.7%). Growth was dose-dependent over the range of Cu treatments (0-54 microg Cu l(-1)), and was modeled as a function of Cu exposure concentration and exposure duration. Calculated inhibition concentrations (based on change in wet weight through a 56-day Cu exposure) were IC(50)=54.0 microg Cu l(-1), IC(20)=21.6 microg Cu l(-1), IC(10)=10.8 microg Cu l(-1), and IC(01)=1.1 microg Cu l(-1). Measured whole body Cu was also dose-dependent, and growth of trout fry was readily modeled as a function of tissue Cu and exposure duration. This model was virtually identical to a model previously developed for rainbow trout exposed to Cu at a hardness of 25 mg l(-1). Following the 56-day exposure period, we performed a 96-h acute challenge to Cu and Cd to evaluate the effects of Cu acclimation on acute Cu and Cd toxicity. Sensitivity to Cu was dependent on the 'acclimation dose'; trout previously held in control aquaria (i.e. not acclimated to Cu) suffered over 80% mortality, whereas trout previously exposed to 35.7 microg Cu l(-1) for 56 day suffered 20% mortality. These fish also showed somewhat reduced sensitivity to Cd, suggesting acclimation to Cu can enhance tolerance to other metals. Finally, the relationship between growth response and hardness (derived from several studies) appeared to have a different slope than the hardness relationship previously observed for lethality responses.

Early hematopoietic reconstitution after clinical stem cell transplantation: evidence for stochastic stem cell behavior and limited acceleration in telomere loss

Our inability to purify hematopoietic stem cells (HSCs) precludes direct study of many aspects of their behavior in the clinical hematopoietic stem cell transplantation (HSCT) setting. We indirectly assessed stem/progenitor cell behavior in the first year after HSCT by examining changes in neutrophil telomere length, X-inactivation ratios, and cycling of marrow progenitors in 25 fully engrafted allogeneic HSCT recipients. Donors were sampled once and recipients at engraftment and 2 to 6 months and 12 months after HSCT. Telomere length was measured by an in-gel hybridization technique, X-inactivation ratios were measured by the human androgen receptor assay, and cell cycle status was determined by flow cytometric analysis of pyronin Y- and Hoechst 33342-stained CD34(+)CD90(+) and CD34(+)CD90(-) marrow cells. Compared with their donors, recipients' telomeres were shortened at engraftment (-424 base pairs [bp]; P <.0001), 6 months (-495 bp; P =.0001) after HSCT, and 12 months after HSCT (-565 bp; P <.0001). There was no consistent pattern of change in telomere length from 1 to 12 months after HSCT; marked, seemingly random, fluctuations were common. In 11 of 11 informative recipients, donor X-inactivation ratios were faithfully reproduced and maintained. The proportion of CD34(+)CD90(+) progenitors in S/G(2)/M was 4.3% in donors, 15.7% at 2 to 6 months (P <.0001) after HSCT, and 11.5% at 12 months after HSCT (P <.0001, versus donors; P =.04, versus 2-6 months). Cycling of CD34(+) CD90(-) progenitors was largely unchanged. We infer that (1) HSCT-induced accelerated telomere loss is temporary and unlikely to promote graft failure or clonal hematopoietic disorders and (2) the striking fluctuations in telomere length and variation in pattern of telomere loss reflect stochastic determination of HSC fate after HSCT.