Alemtuzumab (Campath-1H) in the treatment of chronic lymphocytic leukemia.

Alemtuzumab (Campath-1H) is a humanized IgG1 monoclonal antibody that targets the human CD52 antigen. CD52 is expressed by a variety of lymphoid neoplasms and most human mononuclear cell subsets. In 2001, alemtuzumab was approved for marketing in the United States and Europe for use in patients with fludarabine-refractory chronic lymphocytic leukemia (CLL). In heavily pretreated patients with CLL, the overall response rate (ORR) is approximately 35%, and in previously untreated patients the ORR is greater than 80%, with a recent randomized study suggesting it is superior to alkylator-based therapy. Importantly, alemtuzumab is effective in patients with high-risk del(17p13.1) and del(11q22.3) CLL. Alemtuzumab combination studies with fludarabine and/or monoclonal antibodies such as rituximab have demonstrated promising results. Alemtuzumab is also being studied in CLL patients as consolidation therapy for treatment of minimal residual disease, in preparation for stem cell transplantation and to prevent acute and chronic graft versus host disease. Alemtuzumab is frequently associated with acute 'first-dose' reactions when administered intravenously, but is much better tolerated when administered subcutaneously without loss of therapeutic efficacy. Additional potential adverse events associated with alemtuzumab administration include myelosuppression as well as profound cellular immune dysfunction with the associated risk of viral reactivation and other opportunistic infections. Additional studies detailing the mechanism of action of alemtuzumab as well as new strategies for prevention of opportunistic infections will aid in the future therapeutic development of this agent.

A single center's experience using four different front line mobilization strategies in lymphoma patients planned to undergo autologous hematopoietic cell transplantation.

In an otherwise eligible patient with relapsed lymphoma, inadequate mobilization of hematopoietic stem cells (HSCs) is a limiting factor to proceeding with an autologous hematopoietic cell transplantation (auto-HCT). Multiple strategies have been used to mobilize an adequate number of HSCs with no obvious front-line strategy. We report a single institutional experience mobilizing HSCs using four different approaches in lymphoma patients. We prospectively collected mobilization outcomes on patients planned to undergo auto-HCT at Ohio State University. We report results of first mobilization attempts for all relapsed or refractory lymphoma patients between 2008 and 2014. We identified 255 lymphoma patients who underwent mobilization for planned auto-HCT. The 255 lymphoma patients underwent the following front line mobilization strategies: 95 (37%) G-CSF alone, 38 (15%) chemomobilization (G-CSF+chemotherapy), 97 (38%) preemptive day 4 plerixafor, and 25 (10%) rescue day 5 plerixafor. As expected, there were significant differences between cohorts including age, comorbidity indices, histology, and amount of prior chemotherapy. After controlling for differences between groups, the odds of collecting 2 × 106/kg HSCs on the first day of collection and 5 × 106/kg HSCs in total was the highest in the cohort undergoing chemomobilization. In conclusion, our experience highlights the effectiveness of chemomobilization.

Incidence and description of autoimmune cytopenias during treatment with ibrutinib for chronic lymphocytic leukemia.

Chronic lymphocytic leukemia (CLL) is frequently complicated by secondary autoimmune cytopenias (AICs). Ibrutinib is an irreversible inhibitor of Bruton's tyrosine kinase approved for the treatment of relapsed CLL and CLL with del(17p). The effect of ibrutinib treatment on the incidence of AIC is currently unknown. We reviewed medical records of 301 patients treated with ibrutinib, as participants in therapeutic clinical trials at The Ohio State University Comprehensive Cancer Center between July 2010 and July 2014. Subjects were reviewed with respect to past history of AIC, and treatment-emergent AIC cases were identified. Before starting ibrutinib treatment, 26% of patients had experienced AIC. Information was available for a total of 468 patient-years of ibrutinib exposure, during which there were six cases of treatment-emergent AIC. This corresponds to an estimated incidence rate of 13 episodes for every 1000 patient-years of ibrutinib treatment. We further identified 22 patients receiving therapy for AIC at the time ibrutinib was started. Of these 22 patients, 19 were able to discontinue AIC therapy. We found that ibrutinib treatment is associated with a low rate of treatment-emergent AIC. Patients with an existing AIC have been successfully treated with ibrutinib and subsequently discontinued AIC therapy.

Dinaciclib is a novel cyclin-dependent kinase inhibitor with significant clinical activity in relapsed and refractory chronic lymphocytic leukemia.

Dinaciclib (SCH727965) is a selective CDKi chosen for clinical development based upon a favorable therapeutic index in cancer xenograft models. We performed a phase I dose escalation study of dinaciclib in relapsed and refractory chronic lymphocytic leukemia (CLL) patients with intact organ function and WBC<200 × 10(9) /l. Five separate dose levels (5 mg/m(2), 7 mg/m(2), 10 mg/m(2), 14 mg/m(2) and 17 mg/m(2)) were explored dosing on a weekly schedule × 3 with 1 week off (4-week cycles) using a standard 3+3 design with expansion cohorts to optimize safety. Fifty-two patients were enrolled with relapsed and refractory CLL. Escalation through cohorts occurred with two dose-limiting toxicity (DLTs) at the 17 mg/m(2) dose (tumor lysis syndrome (TLS) and pneumonia). The phase II expansion occurred at 14 mg/m(2) with 16 patients receiving this dose with one DLT (TLS). Additional stepped up dosing to the maximum tolerated dose was examined in 19 patients at this dose. Adverse events included cytopenias, transient laboratory abnormalities and TLS. Responses occurred in 28 (54%) of patients independent of del(17)(p13.1) with a median progression-free survival of 481 days. Dinaciclib is clinically active in relapsed CLL including those patients with high risk del(17)(p13.1) disease and warrants future study.

Tumor antigen ROR1 targeted drug delivery mediated selective leukemic but not normal B-cell cytotoxicity in chronic lymphocytic leukemia.

Selective cytotoxicity to cancer cells without compromising their normal counterparts pose a huge challenge for traditional drug design. Here we developed a tumor antigen-targeted delivery of immunonanoparticle carrying a novel non-immunosuppressive FTY720 derivative OSU-2S with potent cytotoxicity against leukemic B cells. OSU-2S induces activation of protein phosphatase 2A (PP2A), phosphorylation and nuclear translocation of SHP1(S591) and deregulation of multiple cellular processes in chronic lymphocytic leukemia (CLL) resulting in potent cytotoxicity. To preclude OSU-2S-mediated effects on these ubiquitous phosphatases in unintended cells and avoid potential adverse effects, we developed an OSU-2S-targeted delivery of immunonanoparticles (2A2-OSU-2S-ILP), that mediated selective cytotoxicity of CLL but not normal B cells through targeting receptor tyrosine kinase ROR1 expressed in leukemic but not normal B cells. Developing a novel spontaneous CLL mouse model expressing human ROR1 (hROR1) in all leukemic B cells, we demonstrate the therapeutic benefit of enhanced survival with 2A2-OSU-2S-ILP in vivo. The newly developed non-immunosuppressive OSU-2S, its delivery using human CLL directed immunonanoparticles and the novel transgenic (Tg) mouse model of CLL that expresses hROR1 exclusively in leukemic B cell surface are highly innovative and can be applied to CLL and other ROR1+ malignancies including mantle cell lymphoma and acute lymphoblastic leukemia.

An effective mobilization strategy for lymphoma patients after failed upfront mobilization with plerixafor.

In an otherwise eligible patient, inadequate mobilization of PBSCs is a limiting factor to proceeding with an auto-ASCT. In such situations, plerixafor is commonly added to improve PBSC collection yields along with cytokine (G-CSF alone) or chemomobilization (chemotherapy+G-CSF). Individually, both strategies are proven to be safe and effective. Here we report six patients who underwent successful mobilization with combination chemomobilization plus plerixafor after upfront failure of cytokine mobilization plus plerixafor. The median CD34(+) cell yield after chemomobilization was 2.48 × 10(6)/kg (range 0.99-8.49) after receiving one to two doses of plerixafor. All patients subsequently underwent ASCT without major unforeseen toxicities and engrafted successfully. No significant delays in time to neutrophil recovery were observed. Our experience highlights the safety and effectiveness of chemomobilization with plerixafor after G-CSF plus plerixafor (G+P) failure and suggests this is a viable salvage strategy after initial failed G+P mobilization.

The hematopoietic stem cell transplant comorbidity index can predict for 30-day readmission following autologous stem cell transplant for lymphoma and multiple myeloma.

Patients who undergo autologous stem cell transplant (ASCT) for hematologic malignancies frequently have multiple comorbidities. The hematopoietic cell transplantation comorbidity index (HCT-CI), a transplant-specific modification of the Charlson comorbidity index, can predict risk of readmission following allogeneic stem cell transplant. Its utility in the autologous setting is unknown. We evaluated 620 patients who underwent ASCT at the Ohio State University from 2007 to 2012 for lymphoma or multiple myeloma (MM) to identify factors associated with readmission. Univariable and multivariable logistic regression were used to estimate the odds of readmission within 30 days of discharge following ASCT. A Cox proportional hazards model was used to evaluate OS. Sixty-four patients were readmitted within 30 days; the most common indications were fever and prolonged gastrointestinal toxicity. MM compared with lymphoma (odds ratio (OR) 1.89, 95% confidence interval (95% CI): 1.06-3.38, P=0.03), HCT-CI⩾3 (OR 1.74, 95% CI: 1.03-2.96, P=0.04) and length of hospitalization ⩾28 days (OR 3.14, 95% CI: 1.26-7.83, P=0.01) remained significantly associated with 30-day readmission in a multivariable model. While the model had excellent fit (P>0.75), its ability to predict individual patients who would be readmitted was less than acceptable (receiver-operator curve=0.64, 95% CI: 0.57-0.71). In a multivariable proportional hazards model, 30-day readmission (hazards ratio (HR) 1.81, 95% CI: 1.04-3.18, P=0.04), length of hospitalization ⩾28 days (HR 4.93, 95% CI: 2.65-9.18, P<0.001) and chemorefractory disease (HR 3.08, 95% CI: 1.74-5.43, P<0.001) were independently associated with inferior OS, but HCT-CI was not. Evaluation of other assessment tools may allow better prediction of outcomes following ASCT.

The CD37-targeted antibody-drug conjugate IMGN529 is highly active against human CLL and in a novel CD37 transgenic murine leukemia model.

Therapeutic regimens for chronic lymphocytic leukemia (CLL) have increasingly utilized monoclonal antibodies since the chimeric anti-CD20 antibody rituximab was introduced. Despite improved clinical outcomes, current CLL therapies are not curative. Therefore, antibodies with greater efficacy and novel targets are desirable. One promising target is CD37, a tetraspanin protein highly expressed on malignant B-cells in CLL and non-Hodgkin lymphoma. Although several novel CD37-directed therapeutics are emerging, detailed preclinical evaluation of these agents is limited by lack of appropriate animal models with spontaneous leukemia expressing the human CD37 (hCD37) target. To address this, we generated a murine CLL model that develops transplantable hCD37+ leukemia. Subsequently, we engrafted healthy mice with this leukemia to evaluate IMGN529, a novel hCD37-targeting antibody-drug conjugate. IMGN529 rapidly eliminated peripheral blood leukemia and improved overall survival. In contrast, the antibody component of IMGN529 could not alter disease course despite exhibiting substantial in vitro cytotoxicity. Furthermore, IMGN529 is directly cytotoxic to human CLL in vitro, depletes B-cells in patient whole blood and promotes killing by macrophages and natural killer cells. Our results demonstrate the utility of a novel mouse model for evaluating anti-human CD37 therapeutics and highlight the potential of IMGN529 for treatment of CLL and other CD37-positive B-cell malignancies.

Outcomes of hematopoietic SCT recipients with rhinovirus infection: a matched, case-control study.

The impact of rhinovirus in hematopoietic SCT (HSCT) recipients is not well defined. A retrospective, matched, case-control study of HSCT recipients with rhinovirus was conducted between 2009 and 2011. Controls were matched for timing relative to transplant, malignancy, and stem cell source. There were 47 cases and 94 controls. The cases and controls did not differ with respect to age, gender, ethnicity, donor source, malignancy, conditioning regimen, immunosuppression, antimicrobial prophylaxis or significant comorbidities. There were no differences in need for intensive care unit care, 100 day mortality, hospice discharge, relapse of disease, GVHD or development of disease or infection due to CMV or EBV. Other infectious complications after rhinovirus diagnosis were also equal. However, there was an increased number of recurrent hospitalizations from any cause among the cases (46.8% vs 24.5%, P=0.007). Recurrent hospitalizations due to any infection were also more common in cases (34% vs 14.9%, P=0.015). For patients who were diagnosed with rhinovirus pre-transplant (n=13), there was no difference in outcome compared with matched controls. HSCT recipients with rhinovirus have an increased risk of hospital readmission. However, there was no difference in outcome compared with matched controls. Transplantation in patients with active rhinovirus infection appears to be safe.

Association of pre-transplantation positron emission tomography/computed tomography and outcome in mantle cell lymphoma.

Positron emission tomography/computed tomography (PET/CT)-positive findings before autologous SCT (auto-SCT) are associated with inferior PFS and OS in patients with relapsed Hodgkin's and diffuse large B-cell lymphoma. We classified pre-transplant PET/CT performed before auto-SCT as positive or negative to evaluate the impact of pre-transplant PET/CT in mantle cell lymphoma (MCL). In 29 patients, 17 were PET/CT(-) and 12 were PET/CT(+). PET/CT(+) patients were younger (P=0.04), had lower MCL International Prognostic Index (MIPI, P=0.04) scores, but increased bulky adenopathy >5 cm (45% vs 13%, P=0.09). With a median follow-up of 27 months (range: 5-55 months), 7 patients relapsed (4 in the PET/CT(-) group and 3 in the PET/CT(+) group) with 2 deaths in the PET/CT(+) group without a documented relapse. The estimated 2-year PFS was 64% (95% confidence interval (CI): 0.30-0.85) vs 87% (95% CI: 0.57-0.97) in PET/CT(+) and PET/CT(-) patients, respectively (P=0.054). OS was significantly decreased in PET/CT(+) patients (P=0.007), with 2-year estimates of 60% (95% CI: 0.23-0.84) vs 100% in PET/CT(-) patients. A positive pre-transplant PET/CT is associated with a poor prognosis in patients with MCL. Additional factors may impact the prognostic value of PET/CT, as several PET/CT(+) patients remain in remission.

Risk factors for tumor lysis syndrome in patients with chronic lymphocytic leukemia treated with the cyclin-dependent kinase inhibitor, flavopiridol.

Tumor lysis syndrome (TLS) has been described in over 40% of patients with chronic lymphocytic leukemia treated with the cyclin-dependent kinase inhibitor, flavopiridol. We conducted a retrospective analysis to determine predictive factors for TLS. In 116 patients, the incidence of TLS was 46% (95% CI: 36-55%). In univariable analysis, female gender, greater number of prior therapies, Rai stages III-IV, adenopathy ≥ 10 cm, splenomegaly, del(11q), decreased albumin and increased absolute lymphocyte count, white blood cell count (WBC), ß2-microglobulin, and lactate dehydrogenase were associated (P < 0.05) with TLS. In multivariable analysis, female gender, adenopathy ≥ 10 cm, elevated WBC, increased ß2-microglobulin, and decreased albumin were associated with TLS (P < 0.05). With respect to patient outcomes, 49 and 44% of patients with and without TLS, respectively, responded to flavopiridol (P = 0.71). In a multivariable analysis, controlling for number of prior therapies, cytogenetics, Rai stage, age and gender, progression-free survival (PFS) was inferior in patients with TLS (P = 0.01). Female patients and patients with elevated ß2-microglobulin, increased WBC, adenopathy ≥ 10 cm and decreased albumin were at highest risk and should be monitored for TLS with flavopiridol. TLS does not appear to be predictive of response or improved PFS in patients receiving flavopiridol.