Geoffrey Chan

Ofatumumab As Single-Agent CD20 Immunotherapy in Fludarabine-Refractory Chronic Lymphocytic Leukemia

PURPOSE New treatments are needed for patients with fludarabine- and alemtuzumab-refractory (FA-ref) chronic lymphocytic leukemia (CLL) or patients with fludarabine-refractory CLL with bulky (> 5 cm) lymphadenopathy (BF-ref) who are less suitable for alemtuzumab treatment; these groups have poor outcomes with available salvage regimens. Ofatumumab (HuMax-CD20) is a human monoclonal antibody targeting a distinct small-loop epitope on the CD20 molecule. We conducted an international clinical study to evaluate the efficacy and safety of ofatumumab in patients with FA-ref and BF-ref CLL. PATIENTS AND METHODS Patients received eight weekly infusions of ofatumumab followed by four monthly infusions during a 24-week period (dose 1 = 300 mg; doses 2 to 12 = 2,000 mg); response by an independent review committee (1996 National Cancer Institute Working Group criteria) was assessed every 4 weeks until week 24 and then every 3 months until month 24. RESULTS This planned interim analysis included 138 treated patients with FA-ref (n = 59) and BF-ref (n = 79) CLL. The overall response rates (primary end point) were 58% [corrected] and 47% in the FA-ref and BF-ref groups, respectively. Complete resolution of constitutional symptoms and improved performance status occurred in 57% and 48% of patients, respectively. Median progression-free survival and overall survival times were 5.7 and 13.7 months in the FA-ref group, respectively, and 5.9 and 15.4 months in the BF-ref group, respectively. The most common adverse events during treatment were infusion reactions and infections, which were primarily grade 1 or 2 events. Hematologic events during treatment included anemia and neutropenia. CONCLUSION Ofatumumab is an active, well-tolerated treatment providing clear clinical improvements for fludarabine-refractory patients with very poor-prognosis CLL.

Ofatumumab is active in patients with fludarabine-refractory CLL irrespective of prior rituximab: results from the phase 2 international study

Ofatumumab, the human CD20 monoclonal antibody that binds a distinct epitope from rituximab, has demonstrated clinical benefit as monotherapy for patients with chronic lymphocytic leukemia refractory to fludarabine and alemtuzumab (FA-ref) and patients refractory to fludarabine with bulky (> 5 cm) lymph nodes (BF-ref). To potentially gain insight into outcomes in patients previously treated with or refractory to rituximab, we performed an ad hoc retrospective analysis in the final 96 FA-ref and 111 BF-ref patients. There were 117 patients previously treated with rituximab (98 rituximab-refractory); 89 patients were rituximab-naive. For rituximab-treated, rituximab-refractory, and rituximab-naive patients, overall response rate was 43%, 44%, and 53%; median progression-free survival was 5.3, 5.5, and 5.6 months; and median overall survival was 15.5, 15.5, and 20.2 months. There were no significant differences in ofatumumab-related infusion reactions, or hematologic or infectious adverse events between subgroups. In summary, ofatumumab monotherapy was effective and well tolerated in patients with fludarabine-refractory chronic lymphocytic leukemia, including in patients with previous rituximab exposure. This trial was registered at www.clinicaltrials.gov as #NCT00349349.

Chemoimmunotherapy with O-FC in previously untreated patients with chronic lymphocytic leukemia.

We conducted an international phase 2 trial to evaluate 2 dose levels of ofatumumab, a human CD20 mAb, combined with fludarabine and cyclophosphamide (O-FC) as frontline therapy for chronic lymphocytic leukemia (CLL). Patients with active CLL were randomized to ofatumumab 500 mg (n = 31) or 1000 mg (n = 30) day 1, with fludarabine 25 mg/m(2) and cyclophosphamide 250 mg/m(2) days 2-4, course 1; days 1-3, courses 2-6; every 4 weeks for 6 courses. The first ofatumumab dose was 300 mg for both cohorts. The median age was 56 years; 13% of patients had a 17p deletion; 64% had β2-microglobulin > 3.5 mg/L. Based on the 1996 National Cancer Institute Working Group (NCI-WG) guidelines, the complete response (CR) rate as assessed by an independent review committee was 32% for the 500-mg and 50% for the 1000-mg cohort; the overall response (OR) rate was 77% and 73%, respectively. Based on univariable regression analyses, β2-microglobulin and the number of O-FC courses were significantly correlated (P < .05) with CR and OR rates and progression-free survival (PFS). The most frequent Common Terminology Criteria (CTC) grade 3-4 investigator-reported adverse events were neutropenia (48%), thrombocytopenia (15%), anemia (13%), and infection (8%). O-FC is active and safe in treatment-naive patients with CLL, including high-risk patients. This trial was registered at www.clinicaltrials.gov as NCT00410163.

Eltrombopag for children with chronic immune thrombocytopenia (PETIT2): a randomised, multicentre, placebo-controlled trial.

BACKGROUND The thrombopoietin receptor agonist eltrombopag has been shown to be safe, tolerable, and effective for adults with chronic immune thrombocytopenia. We aimed to investigate the safety and efficacy of eltrombopag for children with chronic immune thrombocytopenia. METHODS PETIT2 was a two part, randomised, multicentre, placebo-controlled study done at 38 centres in 12 countries (Argentina, Czech Republic, Germany, Hong Kong, Israel, Italy, Russia, Spain, Taiwan, Thailand, UK, and USA). Paediatric patients aged 1-17 years who had chronic immune thrombocytopenia and platelet counts less than 30 × 10(9) per L were randomly assigned (2:1) to receive eltrombopag or placebo. We stratified patients by age into three cohorts (patients aged 12-17 years, 6-11 years, and 1-5 years) before randomly entering them into a 13 week, double-blind period. Randomisation was done by the GlaxoSmithKline Registration and Medication Ordering System and both patients and study personnel were masked to treatment assignments. Patients who were allocated eltrombopag received tablets (except for those aged 1-5 years who received an oral suspension formulation) once per day for 13 weeks. Starting doses for patients aged 6-17 were based on bodyweight, and ethnic origin and ranged between 50 mg/day and 25 mg/day (starting dose for patients aged 1-5 years was 1·2 mg/kg/day or 0·8 mg/kg/day for east Asian patients). Patients who completed the double-blind period entered a 24 week open-label treatment period in which all patients received eltrombopag at either the starting dose (if they were formerly on placebo) or their established dose. The primary outcome was the proportion of patients achieving platelet counts of at least 50 × 10(9) per L in the absence of rescue therapy for 6 or more weeks from weeks 5 to 12 of the double-blind period. The intention-to-treat population included in the efficacy assessment consisted of all patients who were randomly assigned to one of the treatment groups, and the safety population included all patients who received at least one dose of study drug. This trial is registered with ClinicalTrials.gov, number NCT01520909. FINDINGS Beginning in March 15, 2012, 92 patients were enrolled, and the trial was completed on Jan 2, 2014. 63 patients were assigned to receive eltrombopag and 29 were assigned to receive placebo. In the double-blind period, three patients discontinued treatment because of adverse events: two patients in the eltrombopag group withdrew because of increased liver aminotransferases and one in the placebo group withdrew because of abdominal haemorrhage. 25 (40%) patients who received eltrombopag compared with one (3%) patient who received placebo achieved the primary outcome of platelet counts of at least 50 × 10(9) per L for 6 of the last 8 weeks of the double-blind period (odds ratio 18·0, 95% CI, 2·3-140·9; p=0·0004). Responses were similar in all cohorts (eltrombopag vs placebo: 39% vs 10% for patients aged 12-17 years, 42% vs 0% for patients aged 6-11 years, and 36% vs 0% for patients aged 1-5 years). Proportionately fewer patients who received eltrombopag (23 [37%] of 63 patients) had WHO grades 1-4 bleeding at the end of the double-blind period than did those who received placebo (16 [55%] of 29 patients); grades 2-4 bleeding were similar (three [5%] patients who received eltrombopag vs two [7%] patients who received placebo). During the 24-week open-label treatment period, 70 [80%] of 87 patients achieved platelet counts of 50 × 10(9) per L or more at least once. Adverse events that occurred more frequently with eltrombopag than with placebo included nasopharyngitis (11 [17%] patients), rhinitis (10 [16%] patients), upper respiratory tract infection (7 [11%] patients), and cough (7 [11%] patients). Serious adverse events occurred in five (8%) patients who received eltrombopag and four (14%) who received placebo. Safety was consistent between the open-label and double-blind periods. No deaths, malignancies, or thromboses occurred during the trial. INTERPRETATION Eltrombopag, which produced a sustained platelet response in 40% of patients with chronic immune thrombocytopenia, is a suitable therapeutic option for children with chronic symptomatic immune thrombocytopenia. We identified no new safety concerns and few patients discontinued treatment because of adverse events. FUNDING GlaxoSmithKline.

Blood stream infection (BSI) and acute GVHD after hematopoietic SCT (HSCT) are associated

Blood stream infection (BSI) and acute GVHD (aGVHD) are serious complications of hematopoietic SCT (HSCT). We hypothesized that the two events were not independent of one another. We studied (1) associations between BSI and aGVHD; and (2) the impact of BSI and/or aGVHD on death within 100 days after HSCT, using a retrospective cohort analysis. Risk factor analysis was carried out using multivariable Cox proportional hazards analyses. Of 211 patients who underwent allogeneic HSCT from January 2000 to December 2005 (58% of whom underwent reduced intensity transplantation), 82 (39%) developed BSI. In 49 patients (23%), grade (gr) 2–4 aGVHD occurred. Early BSI was independently associated with an increased occurrence of subsequent aGVHD gr 2–4. CMV seropositivity was independently associated with decreased occurrence of aGVHD. aGVHD gr 2–4 independently predicted subsequent first BSI. Both BSI and aGVHD gr 2–4 were significant independent predictors of death within 100 days after HSCT. There is a strong, independent association between BSI and aGVHD. Potential explanations include the elaboration of cytokines during BSI favoring the development of aGVHD and/or the immunosuppressive treatment of aGVHD favoring the development of BSI. Future studies should be directed at the mechanistic investigations of this association.BSI and acute GVHD (aGVHD) are serious complications of HSCT. We hypothesized that the two events were not independent of one another. We studied (1) associations between BSI and aGVHD; (2) the impact of BSI and/or aGVHD on death within 100 days after HSCT, employing a retrospective cohort analysis. Risk factor analysis was performed using multivariable Cox proportional hazards analyses. Of 211 subjects undergoing allogeneic HSCT from 1/00–12/05 (58% of whom underwent reduced intensity transplantation), 82 (39%) developed BSI. In 49 patients (23%), grades (gr) 2–4 aGVHD occurred. Early BSI was independently associated with an increased occurrence of subsequent aGVHD gr 2–4. Cytomegalovirus seropositivity was independently associated with decreased occurrence of aGVHD. Acute GVHD gr 2–4 independently predicted subsequent first BSI. Both BSI and aGVHD gr 2–4 were significant independent predictors of death within 100 days after HSCT. There is a strong, independent association between BSI and aGVHD. Potential explanations include the elaboration of cytokines during BSI favoring the development of aGVHD and/or the immunosuppressive treatment of aGVHD favoring the development of BSI. Future studies should be directed at mechanistic investigations of this association.

Safety and tolerability of eltrombopag versus placebo for treatment of thrombocytopenia in patients with advanced myelodysplastic syndromes or acute myeloid leukaemia: a multicentre, randomised, placebo-controlled, double-blind, phase 1/2 trial.

BACKGROUND Patients with myelodysplastic syndrome or acute myeloid leukaemia who are thrombocytopenic and unable to receive disease-modifying therapy have few treatment options. Platelet transfusions provide transient benefit and are limited by alloimmunisation. Eltrombopag, an oral thrombopoietin receptor agonist, increases platelet counts and has preclinical antileukaemic activity. We aimed to assess the safety and tolerability of eltrombopag for the treatment of thrombocytopenia in adult patients with advanced myelodysplastic syndrome, secondary acute myeloid leukaemia after myelodysplastic syndrome, or de-novo acute myeloid leukaemia. METHODS We did this multicentre, randomised, placebo-controlled, double-blind, phase 1/2 trial at 37 centres in ten countries in Europe, east Asia, and the Americas. Patients aged 18 years or older who had relapsed or refractory disease or were ineligible for standard treatments; had platelet counts of less than 30 × 10(9) platelets per L; had 10-50% bone-marrow blasts; or were platelet transfusion dependent were randomly assigned (2:1), via a telephone-based interactive voice-response system (GlaxoSmithKline Registration and Medication Ordering System) with a permuted-block randomisation schedule (block size of three), to receive once-daily eltrombopag or matching placebo dose adjusted from 50 mg to a maximum dose of 300 mg. Randomisation was stratified by presence of poor-prognosis (complex) karyotype (presence of at least three abnormalities, or chromosome 7 abnormalities, vs absence) and bone-marrow blast count (<20% vs ≥20%). Patients and study personnel were masked to treatment allocation. The primary endpoint was safety and tolerability, including adverse events, non-haematological laboratory grade 3-4 toxic effects, and changes in bone-marrow blast counts from baseline. Analysis was by intention to treat. This trial is registered at ClinicalTrials.gov, number NCT00903422. FINDINGS Between May 14, 2009, and May 9, 2013, we randomly assigned 98 patients to receive either eltrombopag (n=64) or placebo (n=34). 63 (98%) patients in the eltrombopag group and 32 (94%) patients in the placebo group had adverse events. The most common adverse events were pyrexia (27 [42%] vs 11 [32%]), nausea (20 [31%] vs 7 [21%]), diarrhoea (19 [30%] vs 6 [18%]), fatigue (16 [25%] vs 6 [18%]), decreased appetite (15 [23%] vs 5 [15%]), and pneumonia (14 [22%] vs 8 [24%]). Drug-related adverse events of grade 3 or higher were reported in six (9%) patients in the eltrombopag group and four (12%) patients in the placebo group. Increases in the proportion of peripheral blasts did not differ significantly between groups. Haemorrhage of grade 3 or higher was reported in ten (16%) patients given eltrombopag and nine (26%) patients given placebo. 21 (33%) patients receiving eltrombopag and 16 (47%) patients receiving placebo died while on treatment. No deaths in patients receiving eltrombopag and two deaths in patients receiving placebo were regarded as treatment related. Post-baseline bone-marrow examinations were done in 40 (63%) patients in the eltrombopag group and 17 (50%) patients in the placebo group. The most common reason for no examination was death before the scheduled 3 month assessment. There were no differences between median bone-marrow blast counts or proportions of peripheral blasts between groups. INTERPRETATION Eltrombopag doses up to 300 mg daily had an acceptable safety profile in patients with advanced myelodysplastic syndrome or acute myeloid leukaemia. The role of eltrombopag in these patients warrants further investigation. FUNDING GlaxoSmithKline.

An open-label, single-arm, phase 1 study to assess biomarker effects, efficacy and safety of ofatumumab in patients with refractory chronic lymphocytic leukemia

This open-label, phase 1 study evaluated the effects of ofatumumab on QTc intervals, safety, efficacy, B-cell and neutrophil counts, complement levels, and cytokine and chemokine concentrations. Fourteen patients with fludarabine-refractory chronic lymphocytic leukemia received 12 ofatumumab infusions. A higher maximum infusion rate of 400 mL/h was tested at the first two doses and was well tolerated. The 43% overall response rate was similar to previous data (42–51%). B-cell depletion was observed along with complement consumption; median C2 and CH50 levels appeared lower during monthly dosing in patients who responded. Responding patients appeared to have higher median levels of certain pro-inflammatory cytokines and lower median levels of certain immunotolerant cytokines than patients who did not respond. Ofatumumab-induced complement-dependent cytotoxicity activity can be detected clinically by measuring complement and may be associated with clinical activity. The potential relationship between changes in complement or cytokines and clinical response to ofatumumab warrants further study.

Assessment of the effect of ofatumumab on cardiac repolarization

Ofatumumab is a human monoclonal antibody that binds to a unique CD20 epitope on the surface of B lymphocytes, resulting in efficient lysis of CD20‐expressing cells via complement‐dependent cytotoxicity and antibody‐dependent cell‐mediated cytotoxicity. The potential effect of ofatumumab on cardiac repolarization and the relationship between ofatumumab concentration and change in corrected QT interval (ΔQTcF) were evaluated in data from three clinical trials in 82 patients with chronic lymphocytic leukemia receiving ofatumumab alone (n = 14), ofatumumab with chemotherapy (n = 33), and chemotherapy alone (n = 35). Because of ofatumumab accumulation, baseline QTcF interval was recorded prior to the first infusion for each patient. No patient had a post‐baseline QTcF interval >480 milliseconds or a ΔQTcF >60 milliseconds; five patients (four on ofatumumab) had a ΔQTcF between 30 and 60 milliseconds. At cycle 6 (week 21; 308 μg/mL), there was an increase in QTcF in patients on ofatumumab treatment, with an estimated between‐treatment difference (90% CI) of 12.5 (4.5, 20.5) milliseconds. However, at the visit with the highest median concentration (week 8; 1386 μg/mL), median ΔQTcF was 4.8 milliseconds. There was no significant relationship between ofatumumab plasma concentration and ΔQTcF. Ofatumumab did not have a clinically significant effect on cardiac repolarization.

Priming GM-CSF and low dose cytarabine (LODAC) in the treatment of high risk and elderly acute myelogenous leukemia (AML) and myelodysplastic syndrome (MDS) patients

6612 Background: Priming of leukemic cells with cytokines may enhance the efficacy of cell cycle chemotherapy. We attempted to use GM-CSF to enhance the effects of low dose cytarabine to increase cell recruitment, and optimize cell cycle chemotherapy in patients who could not tolerate conventional induction chemotherapy. METHODS We evaluated the efficacy of GM-CSF priming with low-dose cytarabine and concomitant hydroxyurea in high risk, elderly AML and advanced MDS patients. Patients received induction chemotherapy with GM-CSF 250mcg/m2/d by continuous infusion days 1-7, hydroxyurea 500 mg po qid day 1 and 500mg po tid days 2-15, and cytarabine 20mg/m2/d by continuous infusion days 2-15. RESULTS Forty-nine patients (26F, 23M) were treated, median age 68.5 years (range 48-85); 78% had no previous treatment, and 22% of patients had a median of 2 prior treatments (range 1-7). All patients were not eligible for standard induction chemotherapy. Following treatment, 44% of the assessable patients had documented aplastic bone marrows. The overall response rate was 49%; 33% with CR and 16% with PR. Median duration of CR was 251 days (range 36-842). The CR for secondary AML was 18%, for de novo AML 38%, and for MDS 67%. None of the patients developed mucositis or alopecia, and no patient had greater than grade I nausea and vomiting. The most common adverse effects were neutropenic fever (68%), atrial fibrillation (7%) and congestive heart failure (5%). Five patients died of treatment related toxicity (sepsis). The median survival for all patients was 150 days, for patients achieving CR was 290 days, and the 1 year survival rate was 24%. CONCLUSIONS GM-CSF priming can enhance the cytoreductive effects of low doses of cytarabine. This combination therapy is well tolerated, and should be explored as an alternative regimen for high risk and elderly AML and advanced MDS patients. No significant financial relationships to disclose.