Subcutaneous Alemtuzumab Research Articles

OUTPATIENT SUBCUTANEOUS ALEMTUZUMAB IS FEASIBLE AND SAFE FOR APLASTIC ANEMIA AND ASSOCIATED WITH HIGH RESPONSE RATES

OUTPATIENT SUBCUTANEOUS ALEMTUZUMAB IS FEASIBLE AND SAFE FOR APLASTIC ANEMIA AND ASSOCIATED WITH HIGH RESPONSE RATES

Population pharmacokinetics of subcutaneous alemtuzumab in kidney transplantation.

Alemtuzumab is a monoclonal antibody used as induction immunosuppressive therapy in kidney transplantation. It targets CD52 on lymphocytes, inducing profound immune cell depletion upon administration. Owing to its off-label status in kidney transplantation, its pharmacokinetic characteristics are largely unknown in this setting, and its current fixed dosing algorithm originates from other populations. We developed a population pharmacokinetic model for alemtuzumab in kidney transplant recipients and investigated the potential of personalized alemtuzumab therapy. In total, 362 pharmacokinetic observations drawn 0-165 days after transplantation were available from 61 adult kidney transplant recipients who received two consecutive doses of 15 mg alemtuzumab subcutaneously. A population pharmacokinetic model was developed using nonlinear mixed-effects modelling and applied to simulate various dosing regimens. The alemtuzumab concentration-time data were best described by a two-compartmental model with first-order absorption and parallel first-order and time-varying concentration-dependent elimination, with between-subject variability on the first-order elimination (39.6%) and central distribution volume (39.6%). Alemtuzumab pharmacokinetics varied with body size, rendering lighter individuals exposed to lympholytic alemtuzumab concentrations (>0.1mg/L) for prolonged durations as compared to their heavier peers. This between-subject variability could be reduced through lean bodyweight-adjusted dosing, showing a twofold to threefold reduction in the slope of the median alemtuzumab exposure over the bodyweight range. Alemtuzumab displays substantial pharmacokinetic variability in kidney transplant recipients, which may warrant a personalized treatment strategy. Lean bodyweight-adjusted dosing poses an option for individualized dosing, but further evaluation of its potential clinical benefit is warranted.

CLONAL EVOLUTION TO ACUTE MYELOID LEUKEMIA FOUR YEARS AFTER ALEMTUZUMAB AND CYCLOSPORINE IMMUNOSUPPRESSION IN A PATIENT WITH VERY SEVERE APLASTIC ANEMIA

Describe a rapid clonal evolution to AML with monossomy 7 in an aplastic anemia (AA) patient. A 17-year-old patient was diagnosed with severe aplastic anemia after a history of fatigue, mucocutaneous bleeding and pancytopenia. Bone marrow (BM) aspirate was hypocellular and had no dysplastic changes. Trephine biopsy confirmed 5% cellularity and absence of increased immature progenitors; reticulin fibrosis was not observed. Conventional cytogenetics showed a 46, XY karyotype; a small paroxysmal nocturnal hemoglobinuria (PNH) clone was present in red cells, neutrophils and monocytes. Chromosome breakage analysis for Fanconi anemia was unremarkable, and telomere length was within the normal range. The patient had no HLA-matched donor, and once hATG was discontinued in Brazil and eltrombopag was unavailable, he was included in a group of patients treated with upfront immunosuppressive therapy (IST) with subcutaneous alemtuzumab and cyclosporine; The patient achieved a partial response after 3 months of treatment. Cyclosporine was gradually tapered and was completely stopped after a year of treatment. This patient was lost to follow-up visits for six months and returned after four years of IST, complaining about worsening of fatigue and gingival bleeding. Complete blood count was notable for a loss of the achieved PR, and the presence of a small population of dysplastic monocytes. Revaluation of BM showed a hypercellular smear, and the presence of 60% of immature myeloid cells composed by myeloblasts and monocytes precursors. BM immunophenotyping was compatible with acute myelomonocytic leukemia. Conventional cytogenetics detected a monosomy of chromosome 7 and a trisomy of chromosome 21. Molecular studies for FLT3 and NPM1 mutations, and RUNX1-RUNX1T1 and CBFB-MYH11 fusion genes were negative. The PNH clone size remained stable. The patient was started on standard AML chemotherapy with cytarabine and daunorubicin. An hematologic complete remission with a negative minimal residual disease was achieved. Due to an acute appendicitis during AML induction, the patient awaits consolidation therapy with an haploidentical hematopoietic stem-cell transplant (HSCT) from his brother. Frontline therapy for severe aplastic anemia patients younger than 40 years who have an HLA-matched sibling donor is HSCT. Triple IST with eltrombopag, hATG and cyclosporine is now considered the standard frontline therapy for patients older than 40 years and those who lack a suitable HLA-matched donor. Once hATG was discontinued in many countries, previous studies have reported outcomes of replacing hATG with rabbit ATG, cyclophosphamide, or alemtuzumab. Clonal evolution to myeloid neoplasms is a recognized complication of IST and patients with AA may develop secondary MDS/AML, with the main associated factors being longer disease duration, presence of mutations with an adverse prognosis, a short telomeric length and the development of cytogenetic abnormalities (CAs). The most recurrent CAs include total or partial loss of chromosome 7, trisomy 8 and 13q deletion, and, less frequently, trisomy 6, trisomy 15 and trisomy 21. T-cell-mediated autoimmune diseases, such as AA, have a higher risk of progression to AML/MDS dur to development of somatic mutations and CAs. Monosomy 7 independently represents a poor prognostic factor due to the high rate of progression to acute leukemia, such as occurred with the patient reported.

Model-informed precision dosing for alemtuzumab in paediatric and young adult patients undergoing allogeneic haematopoietic cell transplantation.

Alemtuzumab concentration and absolute lymphocyte count (ALC) profiles were obtained from 29 paediatric and young adult patients (median age 6.4y; range 0.28-21.4y) with nonmalignant disorders undergoing HCT. PK/PD analyses were performed using nonlinear mixed effects modelling. Monte Carlo simulation was conducted to evaluate different improved dosing approaches. A one-compartment model with sequential zero- and first-order absorption adequately described subcutaneously administered alemtuzumab PK. Model fit was significantly improved by including allometrically scaled body weight on clearance (0.080 L/h/70 kg) and volume of distribution (17.4L/70 kg). ALC reduction following subcutaneous alemtuzumab was swift. An inhibitory Emax model best characterized the relationship between alemtuzumab concentration and ALC. Emax and EC50 were estimated as 1.18 × 103 /μL and 0.045 μg/mL, respectively. The currently used per kg dosing was found to cause uneven alemtuzumab exposure across different age and weight cohorts. Simulations indicated optimal target achieving dose as allometry-based dose of 18 mg × (weight/70)0.75 or body surface area-based dose of 10mg/m2 , divided over 3days, with a potential individualized top-up dose; both of which yielded similar results. An allometry- or body surface area-based starting dosing regimen in combination with individualized Bayesian PK estimation using concentration feedback is proposed for alemtuzumab precision dosing in children undergoing allogeneic HCT.

Alemtuzumab for Treatment-Naïve and Relapsed-Refractory Severe Acquired Aplastic Anemia

Introduction: Antithymocyte globulin (ATG) + cyclosporine is effective in restoring hematopoiesis in severe aplastic anemia (SAA). Horse ATG appears to be better than rabbit ATG. Limitations to ATG use in developing countries include cost, horse ATG availability and the reduced number of hospital beds in hematology treatment centers are frequent. Alemtuzumab, a humanized anti-CD52 mAb, might be active in SAA because of its lymphocytotoxic properties. Subcutaneous alemtuzumab have about ORR 66% and is available in Brazil through a compassionate use program. Methods: Fourteen consecutive transplant-ineligible SAA patients were treated. Alemtuzumab was administered subcutaneously in a single at escalating dose of 3-10-30-(30)-(30) mg. Premedication included intravenous steroid, antihistamine and oral acetaminophen. The total dose was 103 mg for 14 patients, and 43 mg for one elderly frail patient. Low dose (1 mg/kg) oral cyclosporine was started on day 7, and then adjusted according to plasma levels (targeting 100-200 ng/ml using a monoclonal assay) at the time of immune reconstitution. Anti-infectious prophylaxis included oral acyclovir and trimethoprim-sulphametoxazole, weekly monitoring of CMV viraemia, and oral quinolone and fluconazole in case of severe neutropenia (<0.5x 109/L). Results: Fifteen SAA patients were treated. Primary outcome was hematologic response at 3months. Median age was 48 years, and 9 (60%) were male. Eight patients were treatment-naive, and 7 (46%) were relapsed-refractory. Eight patients presented PNH clone at the initial investigation, with a size clone between 0.001 to 55 in granulocytes and 0.001 to 98 in monocytes. Median time between SAA diagnosis and alemtuzumab treatment was 9 months (range 1-300). No treatment-related serious adverse events due were observed. Infectious complications were rare. The overall response rate was 66% (60% with PR, 40% CR). The median follow-up is about 29 months (range 5-69). The 3-year overall survival was 73%. Conclusion: The combination of subcutaneous alemtuzumab + cyclosporine appears to be effective and sufficiently safe in transplant-ineligible SAA patients. Moreover, it is feasible in a scenario of limited resources and low accessibility to ATG. DisclosuresNo relevant conflicts of interest to declare.

Subcutaneous Alemtuzumab Has Activity in Treatment-Naïve Patients with Acquired Aplastic Anemia

Subcutaneous Alemtuzumab Has Activity in Treatment-Naïve Patients with Acquired Aplastic Anemia

New lessons learned in T-PLL: results from a prospective phase-II trial with fludarabine–mitoxantrone–cyclophosphamide–alemtuzumab induction followed by alemtuzumab maintenance

Clinical trials in T-cell prolymphocytic leukemia (T-PLL) are scarce. Based on a precursor study testing fludarabine, mitoxantrone, and cyclophosphamide followed by alemtuzumab (FMC-A), we aimed to improve this regimen by upfront combining subcutaneous (s.c.) alemtuzumab with FMC for four cycles followed by an alemtuzumab-maintenance (FMCA + A). This prospective multicenter phase-II trial assessed response, survival, and toxicity of that regimen administered to pretreated (n = 4) and treatment-naïve (n = 12) T-PLL patients. The best overall response rate after FMCA was 68.8% (n = 11) including five CRs (31.3%) and six PRs (37.5%). Six patients entered the alemtuzumab-maintenance. Median overall and progression-free survival was 16.7 and 11.2 months, respectively. Hematologic toxicities were the most frequent grade 3/4 side effects. A reduced incidence of CMV-reactivations was attributed to the prophylactic administration of valganciclovir. Overall, FMCA + A did not improve the efficacy of the FMC-A-regimen or of single i.v. alemtuzumab. It suggests that a chemotherapy backbone prevents efficient alemtuzumab dosing and confirms that intravenous alemtuzumab is to be preferred over its s.c. route in T-PLL.Trial registration: ClinicalTrials.gov identifier: NCT01186640.

Pretransplant Absolute Lymphocyte Counts Impact the Pharmacokinetics of Alemtuzumab

Alemtuzumab is frequently used as part of reduced-intensity conditioning (RIC) regimens for allogeneic hematopoietic cell transplantation (HCT) in pediatric patients with nonmalignant diseases. We previously suggested an optimal day 0 targeted range of alemtuzumab, but there are no pediatric data regarding the pharmacokinetics (PK) of subcutaneous alemtuzumab to guide precision dosing trials. The goal of this study was to prospectively characterize alemtuzumab PK and to explore absolute lymphocyte count (ALC) as a predictor of interindividual variability. We prospectively enrolled 23 patients who received an alemtuzumab, fludarabine, and melphalan RIC regimen. Seventeen patients completed study and received 1 mg/kg alemtuzumab divided over 5 days subcutaneously, starting on day −14. The median age was 7 years (range, .5 to 18). Blood sampling for PK measurements and descriptive PK analyses were performed. The median maximum alemtuzumab concentration was 2.39 µg/mL (interquartile range, 1.98 to 2.92). The median terminal half-life was 5.2 days (interquartile range, 2.7 to 7.8). The median concentration at day 0 was 1.27 µg/mL (interquartile range, .35 to 1.51). Importantly, day 0 alemtuzumab levels and area under the curve negatively correlated with predose ALC and ALC area-time, respectively. In conclusion, we reported the PK of subcutaneous alemtuzumab given to pediatric allogeneic HCT patients and observed that almost all patients have persistence of lytic levels of alemtuzumab beyond day 0, at levels in excess of that needed to reduce the risk of acute graft-versus-host disease. Additionally, levels correlate with pretransplant ALC. These results will allow the development of population PK models for precision dosing trials.

Precision Dosing of Alemtuzumab: Population Pharmacokinetic Modeling in Pediatric Patients Undergoing Allogeneic Hematopoietic Cell Transplantation for Non-Malignant Diseases

INTRODUCTION:A commonly utilized reduced intensity conditioning (RIC) for allogeneic hematopoietic cell transplantation (HCT) of patients with non-malignant disorders consists of alemtuzumab (Campath), fludarabine, and melphalan. Our group recently showed that the risks of acute graft vs host disease (GVHD) and the development of mixed chimerism following this regimen are determined by the peri-transplant levels of alemtuzumab, and recommended a potential optimal Day 0 (D0) alemtuzumab level in the range of 0.2-0.4 µg/mL (Marsh et al, Blood 2016). Additionally, patients with Day 0 alemtuzumab levels >0.6ug/mL also had delayed immune reconstitution post-transplant.We have since conducted a prospective 'intensive sampling' pharmacokinetics (PK) study of subcutaneous alemtuzumab in pediatric patients undergoing HCT (Marsh et al. EBMT Oral Presentation 2016). PK data showed a large inter-individual variability in alemtuzumab exposure and D0 levels. Importantly, levels correlated with pre-transplant absolute lymphocyte count (ALC) and underlying diagnoses. Due to the direct effects of alemtuzumab levels on important HCT outcomes, it is desirable to optimize its dosing. Ideal dosing will be where there is adequate alemtuzumab on D0 to prevent acute GVHD but not too much so as to increase the risk of mixed chimerism and/or delay early post-HCT immune recovery. In order to support targeted precision dosing of alemtuzumab in a prospective clinical trial, we have developed a population PK (PPK) model for Bayesian adaptive control.METHODS: Pediatric patients (n=17) with non-malignant disorders receiving subcutaneous alemtuzumab as a part of their preparative regimen were prospectively enrolled in our 'intensive sampling' PK study. The median age of patients was 7.0 years (3.0-11.0) and median weight was 32.2 kg (16.2-58.9). Alemtuzumab was subcutaneously administered starting on Day -14 at a dose of 0.2 mg/kg/day for 5 days (total dose of 1 mg/kg). Alemtuzumab plasma concentrations were quantified by validated flow cytometric assay. The plasma concentrations at pre-dose, 30 minutes, and 8 hours after each dose, followed by daily levels until Day 0 were used for PPK analysis. PPK analysis was performed using nonlinear mixed effects modeling (NONMEM, version 7.2). Bayesian estimation was conducted using MW/Pharm software (version 3.6).RESULTS: A one-compartment model with first order absorption best described the PK of alemtuzumab (Figure 1). Model fit was significantly improved by including body weight with allometric scaling for clearance and the volume of distribution (p<0.01). Goodness-of-fit plots did not show systematic bias. Model parameter estimates were within the 95% CIs of median values obtained by bootstrap analysis. Bayesian estimation with the developed PPK resulted in well predicted alemtuzumab concentration-time profiles in each patient (Figure 2).CONCLUSION:This is a first study to develop a PPK model of alemtuzumab after subcutaneous administration in pediatric transplant patients. Our model can be used for Bayesian estimation of individual PK to support alemtuzumab precision dosing in pediatric patients undergoing allogeneic HCT using the alemtuzumab, fludarabine, and melphalan containing RIC. Precision dosing of alemtuzumab will in turn optimize transplant outcomes for these high risk patients, by minimizing acute GVHD and mixed chimerism, along with improving post-HCT immune reconstitution. [Display omitted] [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Treatment of relapsed/refractory chronic lymphocytic leukemia/small lymphocytic lymphoma with everolimus (RAD001) and alemtuzumab: a Phase I/II study

Patients with relapsed/refractory chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL), and especially those with purine analogue refractory disease or TP53 deletion/mutation, had a poor prognosis prior to the introduction of therapy targeting B cell receptor signaling. The mammalian target of rapamycin (mTOR) inhibitor everolimus has biological activity in CLL and can mobilize CLL cells from the lymphoid tissues into the circulation. In this clinical trial we determined the maximum tolerated dose (MTD) of everolimus together with eight weeks of standard dose subcutaneous alemtuzumab (Phase I) and then evaluated the tolerability and efficacy of therapy of relapsed/refractory CLL with the combination of everolimus and alemtuzumab (Phase II). The maximum tolerated dose of oral everolimus was 2.5 mg three times/week. Therapy with everolimus and alemtuzumab was tolerable, but not sufficiently efficacious (33% partial responses, no complete responses) to recommend further development of the regimen.

Comparison of Subcutaneous versus Intravenous Alemtuzumab for Graft-versus-Host Disease Prophylaxis with Fludarabine/Melphalan–Based Conditioning in Matched Unrelated Donor Allogeneic Stem Cell Transplantation

The objective of this study was to compare infusion-related reactions and outcomes of using subcutaneous (subQ) alemtuzumab versus intravenous (i.v.) alemtuzumab as graft-versus-host disease (GVHD) prophylaxis for matched unrelated donor stem cell transplantations. Outcomes include incidence of cytomegalovirus (CMV)/Epstein-Barr (EBV) viremia, development of CMV disease or post-transplantation lymphoproliferative disorder, fatal infections, acute and chronic GVHD, time to engraftment, relapse rate, and survival. We conducted a retrospective study of all adult matched unrelated donor stem cell transplantations patients who received fludarabine/melphalan with subQ or i.v. alemtuzumab in combination with tacrolimus as part of their conditioning for unrelated donor transplantation at New York-Presbyterian/Weill Cornell Medical Center from January 1, 2012 to March 21, 2014. Alemtuzumab was administered at a total cumulative dose of 100 mg (divided over days −7 to −3). Forty-six patients received an unrelated donor stem cell transplantation with fludarabine/melphalan and either subQ (n = 26) or i.v. (n = 20) alemtuzumab in combination with tacrolimus. Within the evaluable population, 130 subQ and 100 i.v. alemtuzumab doses were administered. For the primary outcome, ≥grade 2 infusion-related reactions occurred in 11 (8%) versus 25 (25%) infusions in the subQ and i.v. cohorts, respectively (P = .001). Overall, 12 injections (9%) in the subQ arm versus 26 infusions (26%) in the i.v. arm experienced an infusion-related reaction of any grade (P = .001). There were no significant differences between the subQ and i.v. arms in rates of reactivation of CMV/EBV, development of CMV disease or post-transplantation lymphoproliferative disorder, fatal infections, acute and chronic GVHD, relapse, or survival. Subcutaneous administration of alemtuzumab for GVHD prophylaxis was associated with fewer infusion-related reactions compared with i.v. administration in the SCT setting. Incidences of acute and chronic GVHD were similar between both arms. There was also no difference in reactivation of CMV/EBV viremia, development of CMV disease or post-transplantation lymphoproliferative disorder, fatal infections, relapse, or survival.

A Phase 2 Trial of Fludarabine Combined With Subcutaneous Alemtuzumab for the Treatment of Relapsed/Refractory B-Cell Chronic Lymphocytic Leukemia

Alemtuzumab is effective in fludarabine-refractory patients with chronic lymphocytic leukemia. We performed a phase 2 study of alemtuzumab in combination with fludarabine in patients with relapsed disease. Patients received alemtuzumab and fludarabine daily on days 1 to 5 of a 28-day cycle for up to 6 cycles with the primary objective of determining the rate of complete response. Of 60 enrolled patients, 51 had previously received fludarabine, and 60% had received 3 or more prior therapies. Five patients experienced complete response (8.3%) and 12 experienced partial response, yielding an overall response rate of 28.3% for the intention-to-treat population. Among the 41 patients who completed at least 4 cycles of therapy, the complete response rate was 20%. Median progression-free survival was 211 days. Forty-seven percent of patients experienced cytomegalovirus viremia, including 4 patients with symptomatic cytomegalovirus disease. All patients responded to antiviral therapy. Despite some evidence of efficacy in this setting, the primary end point for the study was not met. In the era of targeted agents that are well tolerated, the combination of fludarabine and alemtuzumab should be used rarely for a select group of fit patients who are refractory to standard therapies.

Impact of Alemtuzumab Therapy and Route of Administration in T-Prolymphocytic Leukemia: A Single-Center Experience.

We conducted a single-center retrospective analysis to determine the impact of the anti-CD52 monoclonal antibody alemtuzumab including route of administration compared to non-alemtuzumab-containing regimens in T-prolymphocytic leukemia (T-PLL). The study was a retrospective analysis of a consecutive cohort of adult patients diagnosed with T-PLL at Mayo Clinic Rochester from January 1, 1997, through September 30,2014. A total of 41 patients were diagnosed with T-PLL per the World Health Organization 2008 classification. The median age was 66 years, and 23 (56%) were male. After a median follow-up of 18 months (range, 0.4-66.1 months), 32 patients (78%) had died, with a median overall survival of 16.9 months. Approximately half the cohort was treated with alemtuzumab, almost exclusively after 2004. Median survival for patients receiving intravenous alemtuzumab-based therapy was 40.5 versus 10.3 months for all other therapies (P= .0004). A significant survival difference between intravenous versus subcutaneous alemtuzumab administration of 40.5 versus 13.7 months was noted (P= .0014). Only 4 (14%) of 28 patients aged< 70 years underwent hematopoietic stem cell transplantation, with a median survival after transplantation of 4 months. In this large series of T-PLL patients treated at a single tertiary-care center, we confirmed the prior observation of the superiority of intravenous alemtuzumab over other therapies. Hematopoietic stem cell transplantation was feasible in a minority of potentially eligible patients. Early transplant referral should be considered for all eligible patients.

Frontline low-dose alemtuzumab with fludarabine and cyclophosphamide prolongs progression-free survival in high-risk CLL

AbstractThe randomized Haemato Oncology Foundation for Adults in The Netherlands 68 phase 3 trial compared front-line chemotherapy with chemotherapy plus the CD52 monoclonal antibody alemtuzumab for high-risk chronic lymphocytic leukemia, defined as at least 1 of the following: unmutated immunoglobulin heavy chain genes, deletion 17p or 11q, or trisomy 12. Fit patients were randomized to receive either 6 28-day cycles of oral FC chemotherapy (days 1 through 3: fludarabine 40 mg/m2 per day and cyclophosphamide 250 mg/m2 per day: n = 139) or FC plus subcutaneous alemtuzumab 30 mg day 1 (FCA, n = 133). FCA prolonged the primary end point, progression-free survival (3-year progression-free survival 53 vs 37%, P = .01), but not the secondary end point, overall survival (OS). However, a post hoc analysis showed that FCA increased OS in patients younger than 65 years (3-year OS 85% vs 76%, P = .035). FCA also increased the overall response rate (88 vs 78%, P = .036), and the bone marrow minimal residual disease–negative complete remission rate (64% vs 43%, P = .016). Opportunistic infections were more frequent following FCA, but without an increase in treatment related mortality (FCA: 3.8%, FC: 4.3%). FCA improves progression-free survival in high-risk chronic lymphocytic leukemia. As anticipated, FCA is more immunosuppressive than FC, but with due vigilance, does not lead to a higher treatment-related mortality. This study was registered at www.trialregister.nl as trial no. NTR529.

Low-dose subcutaneous alemtuzumab is a safe and effective treatment for chronic acquired pure red cell aplasia

Three patients with pure red cell aplasia, with or without co-existing large granular lymphocytic leukaemia, who remained transfusion-dependent despite treatment with established first-line therapy, were treated with low-dose subcutaneous alemtuzumab 15 mg twice to thrice per week, for 3 to 4 weeks. The mean response time was 17 days compared with a response time of at least 61 days on standard first-line therapy. There were no serious side-effects and the mean duration of remission was 13 months. Low-dose subcutaneous alemtuzumab is a safe and effective treatment for pure red cell aplasia and further trials should be conducted to compare the long-term effectiveness of this treatment with conventional therapy.

Outcomes of Allogeneic Hematopoietic Cell Transplantation In Aplastic Anemia Using Intermediate Dose Alemtuzumab Based-Conditioning

Unlike in hematologic malignancies, graft versus host disease (GVHD) has no therapeutic benefit in aplastic anemia (AA) and its prevention is highly desirable. Using conventional GVHD prophylaxis in AA, 30–40% of patients develop acute and chronic GVHD resulting in significant mortality and morbidity with long-term health issues and poor quality of life. Previous studies reported the favorable effect of alemtuzumab on acute GVHD in related and unrelated donor hematopoietic cell transplantation (HCT) for AA (Gupta et al, BBMT 2004; Gupta et al, BMT 2005). In these studies, a higher dose of alemtuzumab (75-100 mg) close to stem cell infusion was used. We subsequently designed a conditioning strategy using an intermediate dose of alemtuzumab (50-60 mg), and report our institutional experience at Princess Margaret Cancer Centre, Toronto, Canada using this strategy.Between January 2005 and June 2013, 40 patients underwent HCT for AA at our centre. The median age at HCT was 35 years (range 17-59). The etiology of AA was idiopathic in 70%. Fifteen (38%) were positive for paroxysmal nocturnal haemoglobinurea (PNH) clones and 2 patients had symptomatic hemolytic PNH prior to HCT. Upfront HCT was used in 17 (42%) patients, and 23 (58%) had failed one or two courses of ATG-based immunosuppressive therapy (IST). Donors were HLA-identical matched siblings in 28 (70%) and matched unrelated donors (MUD) in 12 (30%). As the preferred source of hematopoietic cells was bone marrow, 34 (85%) received BM grafts and 6 (15%) received peripheral blood grafts. Twenty four (60%) patients were CMV seropositive. Conditioning regimens included: High-dose cyclophosphamide (50 mg/kg x 4 days from days -5 to -2) with alemtuzumab 50 mg (10, 20, 20 mg on days -8, -7 and -6 respectively) in 9 (23%) patients; fludarabine (30 mg/m2 x 4 days from days -5 to -2) with low-dose cyclophosphamide (10 mg/kg x 4 days from days -5 to -2) and alemtuzumab 60 mg (30 mg x 2 days on days -7 and -6) in 28 (70%) patients. In 3 (7%) patients busulphan was used instead of low-dose cyclophosphamide because of symptomatic PNH or presence of monosomy 7. In the first 10 (25%) patients, alemtuzumab was used as an IV infusion; the subsequent 30 (75%) patients received subcutaneous alemtuzumab. Cyclosporine was also used for GVHD prophylaxis starting on day -1 and slowly tapered in the absence of GVHD at 6 months.The median follow up time of survivors was 3.6 years (range 0.2-7.9). The median neutrophil (≥0.5 x109/l) and platelet (≥20 x109/l) engraftment times were 18 days (range 11-112) and 12 (range 2-395) respectively. Four patients had graft failure (2 primary and 2 secondary). Two of these patients died and two are long-term survivors (one after second HCT and the other had autologous recovery). The cumulative incidences of acute and chronic GVHD were 27.7% (95% CI 13.5-41.8) and 21.3% (95% CI 7.9-34.7) respectively. No patients developed grade 3-4 acute GVHD or severe chronic GVHD (NIH criteria). Viral complications were seen frequently: CMV reactivation (79%); HSV (18%); VZV (25%) and BK hemorrhagic cystitis (8%). None developed CMV disease. Three patients developed an EBV-related lymphoproliferative disorder. All three patients were heavily treated with ≥2 courses of ATG- IST prior to HCT.The 3-year estimated overall survival was 85% (95% CI 74-97). The majority of patients had no significant long-term health issues. Of the 18 women of childbearing age (16-45 years), 6 patients conceived. An asymptomatic drop in FEV1 ≥20% was seen in only 4 of 21 patients who had survived >2 years. Two patients developed secondary malignancies (1 smouldering myeloma and 1 squamous cell carcinoma).In conclusion, this intermediate dose alemtuzemab based conditioning in AA is a simplified approach that results in excellent survival and has a favorable impact on GVHD, and long-term health issues. Nevertheless, close monitoring for viral complications such as CMV reactivation, and EBV monitoring particularly in patients who fail IST prior to HCT is important. Disclosures:Off Label Use: Alemtuzumab for GVHD prophylaxis in allogeneic hematopoietic cell transplantation for aplastic anemia.

Alemtuzumab Is Safe and Associated With High Response Rates In Selected Patients With Myelodysplastic Syndrome

▪In a subgroup of patients with myelodysplastic syndrome (MDS) an immune mechanism is believed to cause bone marrow failure. In these individuals immunosuppressive treatment (IST) can restore marrow function. We previously reported a 68% response rate in a phase I/II study of alemtuzumab in 31 patients with low to int-2 risk MDS (Sloand etal JCO Dec 10, 2010:5166-5173). Patients were enrolled according to their predicted probability of response based on an algorithm that incorporated HLA-DR15 positivity, age and transfusion burden (Blood 2003 Oct 15; 102(8):3025-7). We now report updated efficacy data on our cohort of 40 patients and long term follow up data on responders. The first 37 patients received 10mg of alemtuzumab for 10 days intravenously. Alemtuzumab was administered subcutaneously in the subsequent 3 patients. Primary endpoints were changes in peripheral blood counts. Secondary endpoints included improvement in the transfusion requirements (in transfusion- dependent patients), duration of response, and late effects of treatment, relapse and survival. Thirty nine patients were evaluable. One patient discontinued treatment after one dose because of severe hypotension and was excluded from analysis. Median follow-up time was 25 months (3-64 months). Median age was 56 years (23-71 years). The overall response rate (ORR) was 64% (25/39) with 21% of patients having a complete response (8/39). Twenty of 29 (69%) int-1 patients; 4 of 7 (57 %) int-2 patients and 1 of 3 (33%) low risk patients responded following alemtuzumab treatment. Median time to response was 3 months with median duration of response 9 months (range 1-69 months). Eight of 11 patients who relapsed regained their response with addition of cyclosporine and one patient was lost to follow up. The median duration of response in patients rescued with cyclosporine is 37 months (1-42 months). The median duration of response to immunosuppressive treatment (alemtuzumab +/- cyclosporine) is 22.2 months (range 3-69 months). All responding patients who were previously transfusion dependent became transfusion independent after alemtuzumab treatment. One of three patients who received subcutaneous alemtuzumab administration responded. The median survival for all patients was 34 months (range 1-72 months) (figure 1a) with median survival of 36 months (6-72 months) in responding group compared to 16 months (1-56 months) in non-responding group (p<0.001) (figure 1b). Five of twelve patients with abnormal cytogenetics at the start of treatment had a complete cytogenetic remission at one year. One patient with monosomy 7 and another with del 13 were in cytogenetic remission for 4.5 years and 4 years respectively. Decline in their blood counts correlated with re-emergence of initial clone. Three patients with del 13, 5q- and del 5 continue to remain in cytogenetic remission at 4, 2 and 1 years respectively. The absolute neutrophil count at baseline was significantly associated with overall survival on univariate analysis. On multivariate analysis, factors significantly associated with overall survival were male sex, bone marrow hypocellularity/normocellularity, prior immunosuppressive treatment, baseline absolute neutrophil count and platelet count. All patients became lymphopenic after alemtuzumab administration and most patients continued to be lymphopenic at 3 years. Baseline absolute lymphocyte count, ratio of CD4/CD8 cell count, absolute CD4 and NK cell counts and kinetics of lymphocyte recovery were not predictive for response. Alemtuzumab was generally well tolerated with most patients having manageable infusion reactions with the first dose. Sixteen of the 39 patients became transiently positive for EBV DNA and 6 of 29 CMV seropositive patients had reactivation but no patient developed clinically significant viral disease. Alemtuzumab is well tolerated and is effective in a subset of patients with MDS. Long term responses with cytogenetic remissions are possible. Patients who relapse can be rescued with cyclosporine. Immunosuppresion should be considered in patients likely to respond based on a simple algorithm and alemtuzumab is an alternative to ATG based regimens. [Display omitted] [Display omitted] Disclosures:Off Label Use: Alemtuzumab use as immunosuppresive agent in myelodysplastic syndrome.

A phase I study of escalated dose subcutaneous alemtuzumab given weekly with rituximab in relapsed chronic lymphocytic leukemia/small lymphocytic lymphoma

This study assessed the safety and preliminary efficacy of escalated dose subcutaneous alemtuzumab in combination with rituximab in chronic lymphocytic leukemia. Twenty-eight patients with relapsed refractory chronic lymphocytic leukemia were treated on four dosing cohorts of weekly rituximab at 375 mg/m(2) and alemtuzumab doses that started at 30 mg three times per week and escalated to weekly dosing over four weeks, culminating with 90 mg weekly. One dose limiting toxicity of a rituximab infusion reaction was seen in cohort 2, but the regimen was otherwise well tolerated without evidence of differential toxicity by cohort. The overall response rate by National Cancer Institute-Working Group criteria was 61%, and the rate of complete bone marrow response was 43%, most of whom were negative for minimal residual disease. The addition of CT scan evaluation per International Workshop on Chronic Lymphocytic Leukemia 2008 criteria reduced the overall response rate to 14%. Median overall survival was 35 months, with 12 patients able to proceed to stem cell transplantation. Pharmacokinetic studies showed that chronic lymphocytic leukemia involving more than 80% of the bone marrow at study start was associated with lower trough concentrations of alemtuzumab and rituximab, and that higher trough serum concentrations of alemtuzumab were associated with complete bone marrow clearance. We conclude that escalated subcutaneous doses of alemtuzumab given weekly are well tolerated and result in excellent bone marrow clearance of chronic lymphocytic leukemia, helping patients to proceed to stem cell transplantation. This study is registered at ClinicalTrials.gov (Identifier:00330252).

Plasma alemtuzumab levels in patients with chronic lymphocytic leukemia treated with alemtuzumab combined with chemotherapy reflect the efficacy of the treatment: a hypothesis

In the HOVON68 trial comparing subcutaneous low-dose alemtuzumab (LD-A) used together with fludarabine (F) and cyclophosphamide (C) with FC alone in high-risk chronic lymphocytic leukemia (CLL), LD-AFC resulted in significantly more clinical and molecular responses than FC, but also in more opportunistic infections. In a subgroup analysis of alemtuzumab trough levels during treatment by a sensitive enzyme-linked immunosorbent assay (ELISA) method, detectable levels were found in 4/6 complete and 0/3 partial responders. A relationship between alemtuzumab plasma levels, response and duration of lymphocytopenia was evident. We hypothesize that following combination therapy, the response may not be a function of the alemtuzumab levels, but the opposite, that plasma alemtuzumab levels are a function of the efficacy of the entire treatment, and the fewer leukemic target cells that are remaining, the higher are the levels of plasma alemtuzumab. This concept may well provide a guide for alemtuzumab dosage in future trials.

Immune Thrombocytopenia Associated to Low-Dose Alemtuzumab Therapy in Chronic Lymphocytic Leukemia: A Single Retrospective Center Experience

AbstractAbstract 4598Immune thrombocytopenia (ITP) is a common autoimmune complication in chronic lymphocytic leukemia (CLL), occurring in up to 5% of patients. The occurrence of alemtuzumab-associated ITP have been rarely reported in CLL and it has never been reported so far as a significant event complicating alemtuzumab treatment in clinical trials. Recently, a new distinctive form of secondary ITP occurring in 6 out of 215 patients with relapsing-remitting multiple sclerosis treated with alemtuzumab in a randomized, controlled phase II trial has been reported (Cuker et al, Blood 2011).We investigated the incidence of ITP in a cohort of 64 consecutive patients treated with low-dose alemtuzumab for relapsed/refractory CLL from 2003 to 2010. Subcutaneous alemtuzumab was administered at the dose of 10 mg three times a week, up to 18 weeks.ITP was documented in 12/64 patients: in 3 patients (4.7%) ITP developed before alemtuzumab treatment and no relapses of the autoimmune disorder were observed during the treatment; in 9 patients (14.8%, with an incidence of 5.7 events/100 patient-year) ITP developed after alemtuzumab treatment. Median time to ITP from initial alemtuzumab exposure was 12 months (range 1–42 months). Concomitant hemolytic anemia (Evans syndrome) was observed in one patient. At ITP onset, median platelet counts were 11×109/L (range 3–70) and anti-platelet antibodies (Capture P® Method, ImmucorGamma, Norcross GA, USA) were found in 7 of the 8 patients tested. No patients showed severe or life-threatening bleeding. Three of nine patients who developed ITP after alemtuzumab therapy, experienced CLL progression requiring chemo-immunotherapy after 3, 4 and 13 months from ITP onset, respectively. One patient achieved a partial remission of CLL with ITP resolution, while the other two died of disease progression. In the remaining six cases, ITP was not associated with disease progression and was treated with corticosteroids and/or intravenous immunoglobulins. Five patients achieved normal platelet counts, while one patient did not respond.Low-dose alemtuzumab (theoretical cumulative dose 540 mg, equal to half of the classic cumulative dose and one-third of the individual dose) is an effective, safe and well tolerated treatment for CLL, as reported by several recent studies (Cortelezzi et al, Leukemia 2009; Brit J Haematol 2011). In our cohort of CLL patients treated with alemtuzumab, the incidence of ITP was 14.8% that is almost three times higher than previously reported in CLL. These data may indicate a role of T-lymphocyte dysregulation induced by alemtuzumab in the pathogenesis of ITP. Our data also suggested the importance of monitoring platelet counts during follow-up in patients treated with low-dose alemtuzumab for both haematological and non-haematological diseases. Disclosures:No relevant conflicts of interest to declare.