Effect of adding gemtuzumab ozogamicin to induction chemotherapy for newly diagnosed acute myeloid leukemia: a meta-analysis of prospective randomized phase III trials

Toxicity profiles of antibody-drug conjugates for anticancer treatment: a systematic review and meta-analysis

BACKGROUND

Antibody-drug conjugates are attractive targeted agents in anticancer treatment because of their unique mechanism of action and reduced toxicity. Little is known about the spectrum of adverse events associated with antibody-drug conjugates, despite tens of clinical trials.

METHODS

A systematic review of randomized controlled trials evaluating antibody-drug conjugate efficacy in anticancer treatment was conducted. PubMed, EMBASE, and ClinicalTrial.gov were searched for relevant studies. Meta-analyses assessed the odds ratios (ORs) of 12 treatment-related symptoms and toxicities in patients treated with antibody-drug conjugates compared with those receiving other anticancer agents without antibody-drug conjugates. All-grade and high-grade (grade ≥3) toxicities were examined.

RESULTS

Twenty studies involving 10 075 patients were included. Compared with control groups, antibody-drug conjugates were associated with a higher risk of all-grade fatigue (OR = 1.25, 95% confidence interval [CI] = 1.08 to 1.45), anorexia (OR = 1.36, 95% CI = 1.09 to 1.69), nausea (OR = 1.46, 95% CI = 1.09 to 1.97), and sensory neuropathy (OR = 2.18, 95% CI = 1.27 to 3.76) as treatment-related symptoms. Patients treated with antibody-drug conjugates had a statistically significantly lower risk of all-grade febrile neutropenia (OR = 0.46, 95% CI = 0.22 to 0.96). Conversely, they had a higher risk of thrombocytopenia (OR = 2.07, 95% CI = 1.00 to 4.31), increased alanine aminotransferase (OR = 2.51, 95% CI = 1.84 to 3.40), and increased aspartate aminotransferase (OR = 2.83, 95% CI = 2.04 to 3.93). Subgroup analysis showed a similar toxicity profile when comparing the solid tumors with hematologic malignancy groups and the antibody-drug conjugate vs antibody-drug conjugate plus chemotherapy groups, except for some neurologic and hematologic adverse events.

CONCLUSIONS

This comprehensive profile of adverse events associated with antibody-drug conjugate-based treatment shows an increase in various types of all-grade treatment-related symptoms and adverse events, although no increase in high-grade adverse events was seen.

Treatment options for acute myeloid leukemia patients aged <60 years

Treatment of acute myeloid leukemia (AML) has changed over the last few years, after the discovery of new drugs selectively targeting AML blasts. Although 3/7 remains the standard of care for most AML patients, several new targeted agents (such as FLT3 inhibitors, CPX-351, gemtuzumab ozogamicin, BCL-2 inhibitor, and oral azacitidine), either as single agents or combined with standard chemotherapy, are approaching clinical practice, starting a new era in AML management. Moreover, emerging evidence has demonstrated that high-risk AML patients might benefit from both allogeneic stem cell transplant and maintenance therapy, providing new opportunities, as well as new challenges, for treating clinicians. In this review, we summarize available data on first-line therapy in young AML patients focusing on targeted therapies, integrating established practice with new evidence, in the effort to outline the contours of a new therapeutic paradigm, that of a “total therapy”, which goes beyond obtaining complete remission.

Clinical Benefits and Safety of Gemtuzumab Ozogamicin in Treating Acute Myeloid Leukemia in Various Subgroups: An Updated Systematic Review, Meta-Analysis, and Network Meta-Analysis

Background

Previous trials demonstrated evidence involving the total effects of gemtuzumab ozogamicin (GO), an anti-CD33 humanized antibody, on treating acute myeloid leukemia (AML). In this updated systematic review, meta-analysis, and network meta-analysis (NMA), we aimed to comprehensively explore the clinical benefits and safety of GO in various subtypes of AML.

Methods

PubMed, Embase, Cochrane, and Chinese databases were filtered to search randomized controlled trials (RCTs) and retrospective cohort studies that compared clinical efficiency and toxicity of GO with non-GO groups in AML. Random-effects models were used to calculate pooled effect sizes and 95% confidence intervals (CIs). Relative risk (RR) was used for estimating complete remission (CR), early death, and toxicity. Hazard risk (HR) was accomplished to evaluate survival.

Results

Fifteen RCTs and 15 retrospective cohort studies were identified (GO: 4,768; Control: 6,466). GO tended to improve CR (RR 0.95, p = 0.084), followed by significantly improved survival (overall survival: HR 0.86, p = 0.003; event-free survival: HR 0.86, p = 0.015; relapse-free survival: HR 0.83, p = 0.001; cumulative incidence of relapse: HR 0.82, p < 0.001). GO benefits of CR and survival were evident in favorable- and intermediate-risk karyotypes (p ≤ 0.023). GO advantages were also associated with nucleophosmin 1 mutations (p ≤ 0.04), wild-type FMS-like tyrosine kinase 3 internal tandem duplication gene (p ≤ 0.03), age of <70 years (p < 0.05), de novo AML (p ≤ 0.017), and CD33(+) (p ≤ 0.021). Both adding GO into induction therapy (p ≤ 0.011) and a lower (<6 mg/m2) dose of GO (p ≤ 0.03) enhanced survival. Prognosis of combined regimens with GO was heterogeneous in both meta-analysis and NMA, with several binding strategies showing improved prognosis. Additionally, GO was related to increased risk of early death at a higher dose (≥6 mg/m2) (RR 2.01, p = 0.005), hepatic-related adverse effects (RR 1.29, p = 0.02), and a tendency of higher risk for hepatic veno-occlusive disease or sinusoidal obstruction syndrome (RR 1.56, p = 0.072).

Conclusions

These data indicated therapeutic benefits and safety of GO in AML, especially in some subtypes, for which further head-to-head RCTs are warranted.

Systematic Review Registration

[PROSPERO: https://www.crd.york.ac.uk/prospero/], identifier [CRD42020158540].

Gemtuzumab ozogamicin for the treatment of acute myeloid leukemia in adults

INTRODUCTION

Treatment of acute myeloid leukemia (AML) has changed dramatically in the past ten years with the approval of targeted agents, the first of which was the anti-CD33 antibody-drug conjugate gemtuzumab ozogamicin (GO). Despite withdrawal from the market after accelerated approval, GO was reapproved and now has a well-established role in treating select AML patients. CD33 has proven to be an important target for drug development in AML as evidenced by the improvement in survival with GO treatment.

AREAS COVERED

The review summarizes the development of GO, its mechanism of action, initial studies and approval, withdrawal from the market, and subsequent reapproval after the results of several large randomized studies became available. We also provide an overview of its current role in the treatment landscape of AML.

EXPERT OPINION

Multiple phase 3 trials with GO have established a significant benefit with GO in induction therapy for favorable risk AML. Additional studies support the use of GO in relapsed/refractory AML and APL. Despite the withdrawal of GO from the market after initial approval, GO has proven to improve survival of select AML patients when added to induction chemotherapy and in relapsed disease.

Nonclinical Development of Next-generation Site-specific HER2-targeting Antibody-drug Conjugate (ARX788) for Breast Cancer Treatment

Conventional antibody-drug conjugates (ADC) utilize native surface-exposed lysines or cysteines on the antibody of interest to conjugate cytotoxic payload. The nonspecific conjugation results in a mixture with variable drug-to-antibody ratios (DAR), conjugation sites, and ADCs that are often unstable in systemic circulation. ARX788 is an ADC consisting of a HER2-targeting antibody site-specifically conjugated with a potent antitubulin cytotoxic drug-linker, AS269. The site-specific conjugation is achieved by first incorporating the nonnatural amino acid, para-acetyl phenylalanine (pAF), into the antibody, followed by covalent conjugation of AS269 to the pAF to form a highly stable oxime bond resulting in a DAR 2 ADC. ARX788 exhibits significant, dose-dependent antitumor activity against HER2- expressing breast and gastric xenograft tumors. Pharmacokinetic (PK) studies in multiple species showed the highly stable nature of ARX788 with overlapping PK profiles for the intact ADC and total antibody. Metabolism studies demonstrated that pAF-AS269 was the sole major metabolite of ARX788, with no evidence for the release of free drug often observed in conventional ADCs and responsible for adverse side effects. Furthermore, ARX788 demonstrated a favorable safety profile in monkeys with a highest nonseverely toxic dose of 10 mg/kg, which was well above the efficacious dose level observed in preclinical tumor models, thus supporting clinical development of ARX788.

Cardiovascular Toxicity of Targeted Therapies for Cancer: An Overview of Systematic Reviews

Background

Several targeted therapies for cancer have been associated with cardiovascular toxicity. The evidence for this association has not been synthesized systematically nor has the quality of evidence been considered. We synthesized systematic review evidence of cardiovascular toxicity of individual targeted agents.

Methods

We searched MEDLINE, Embase, and the Cochrane Database of Systematic Reviews for systematic reviews with meta-analyses of cardiovascular outcomes for individual agents published to May 2020. We selected reviews according to prespecified eligibility criteria (International Prospective Register of Systematic Reviews CRD42017080014). We classified evidence of cardiovascular toxicity as sufficient, probable, possible, or indeterminate for specific cardiovascular outcomes based on statistical significance, study quality, and size.

Results

From 113 systematic reviews, we found at least probable systematic review evidence of cardiovascular toxicity for 18 agents, including high- and all-grade hypertension for bevacizumab, ramucirumab, axitinib, cediranib, pazopanib, sorafenib, sunitinib, vandetanib, aflibercept, abiraterone, and enzalutamide, and all-grade hypertension for nintedanib; high- and all-grade arterial thromboembolism (includes cardiac and/or cerebral events) for bevacizumab and abiraterone, high-grade arterial thromboembolism for trastuzumab, and all-grade arterial thromboembolism for sorafenib and tamoxifen; high- and all-grade venous thromboembolism (VTE) for lenalidomide and thalidomide, high-grade VTE for cetuximab and panitumumab, and all-grade VTE for bevacizumab; high- and all-grade left ventricular ejection fraction decline or congestive heart failure for bevacizumab and trastuzumab, and all-grade left ventricular ejection fraction decline/congestive heart failure for pazopanib and sunitinib; and all-grade corrected QT interval prolongation for vandetanib.

Conclusions

Our review provides an accessible summary of the cardiovascular toxicity of targeted therapy to assist clinicians and patients when managing cardiovascular health.

Acute Myeloid Leukemia, Version 3.2019, NCCN Clinical Practice Guidelines in Oncology

Acute myeloid leukemia (AML) is the most common form of acute leukemia among adults and accounts for the largest number of annual deaths due to leukemias in the United States. Recent advances have resulted in an expansion of treatment options for AML, especially concerning targeted therapies and low-intensity regimens. This portion of the NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for AML focuses on the management of AML and provides recommendations on the workup, diagnostic evaluation and treatment options for younger (age <60 years) and older (age ≥60 years) adult patients.

Overexpression of annexin A5 might guide the gemtuzumab ozogamicin treatment choice in patients with pediatric acute myeloid leukemia

Background:

Acute myeloid leukemia (AML) is a common hematological malignancy. Gemtuzumab ozogamicin (GO), a humanized anti-CD33 antibody conjugated with the potent anti-tumor antibiotic calicheamicin, represents a promising targeted therapy for AML. Annexin A5 (ANXA5) is a proposed marker for the clinical prognosis of AML to guide treatment choice.

Methods:

In total, 253 patients with pediatric AML were enrolled and divided into two treatment groups: conventional chemotherapy alone and conventional chemotherapy in combination with GO. Univariate, multivariate, and Kaplan–Meier survival analyses were conducted to assess risk factors and clinical outcomes, and to estimate hazard ratios (HRs) and their 95% confidence interval. The level of statistical significance was set at p < 0.05.

Results:

In the GO treatment group, high ANXA5 expression was considered a favorable prognostic factor for overall survival (OS) and event-free survival (EFS). Multivariate analysis showed that high ANXA5 expression was an independent favorable factor for OS (HR = 0.629, p = 0.084) and EFS (HR = 0.544, p = 0.024) distinct from the curative effect of GO treatment. When all patients were again divided into two groups, this time based on the median expression of ANXA5, patients undergoing chemotherapy combined with GO had significantly better OS (p = 0.0012) and EFS (p = 0.0003) in the ANXA5 high-expression group. Gene set enrichment analysis identified a relevant series of pathways associated with glutathione metabolism, leukocyte transendothelial migration, and hematopoietic cell lineage.

Conclusion:

The expression level of ANXA5 can help optimize the treatment regimen for individual patients, and patients with overexpression of ANXA5 may circumvent poor outcomes from chemotherapy combined with GO.

Effect and safety of gemtuzumab ozogamicin for the treatment of patients with acute myeloid leukaemia: a systematic review protocol

INTRODUCTION

Acute myeloid leukaemia (AML) is a type of cancer in which the bone marrow makes abnormal myeloblasts (a type of white blood cell), red blood cells or platelets. Gemtuzumab ozogamicin (GO) holds promise as a new agent that also could be efficacious in newly diagnosed AML with acceptable toxicity. This paper describes the design of a protocol to conduct a systematic review of published studies assessing GO for the treatment of AML.

METHOD AND ANALYSIS

We will conduct a systematic review of randomised controlled trials that investigate the effect and safety of GO for the treatment of patients with AML. We will search for any eligible articles from selected electronic databases. We will follow the Preferred Reporting Items for Systematic reviews and Meta-Analysis for study selection and reporting. We will use The Cochrane Handbook for Systematic Reviews of Interventions and Meta-Analysis as guidance to select eligible studies. All data will be extracted using a standardised data extraction form.

ETHICS AND DISSEMINATION

There was no patient involved in this study, therefore no ethical consideration is needed. The findings of this study will be disseminated in a peer-reviewed journal and any relevant conference presentation.

PROSPERO REGISTRATION NUMBER

CRD42019123286.

Comprehensive preclinical pharmacokinetic evaluations of trastuzumab deruxtecan (DS-8201a), a HER2-targeting antibody-drug conjugate, in cynomolgus monkeys

Trastuzumab deruxtecan (DS-8201a) is an antibody-drug conjugate (ADC) composed of a monoclonal antibody targeting human epidermal growth factor receptor 2 (HER2) conjugated to a topoisomerase I inhibitor (DXd) at a drug-to-antibody ratio (DAR) of 7-8. Here, we examined the pharmacokinetic (PK) profiles of DS-8201a and DXd in cynomolgus monkeys, a cross-reactive species. Following intravenous (iv) administration of DS-8201a, the linker was stable in plasma, and systemic DXd exposure was low. DXd was rapidly cleared following iv dosing. Biodistribution studies revealed that intact DS-8201a was present mostly in the blood without tissue-specific retention. The major pathway of excretion for DXd was the faecal route following iv administration of radiolabelled DS-8201a. The only detectable metabolite in the urine and faeces was unmetabolized DXd. DXd is a substrate of organic anion transporting polypeptides, P-gp, and breast cancer resistance protein. In conclusion, the stable linker in circulation and the high clearance of DXd upon release resulted in the low systemic exposure to DXd. Furthermore, the minimal tissue-specific retention and rapid excretion of DXd into faeces as its unmetabolized form with potentially limited impact on drug - drug interaction as a victim were also critical elements of the PK profile of DS-8201a.

Gemtuzumab ozogamicin for treatment of newly diagnosed CD33-positive acute myeloid leukemia

In September 2017, the US FDA announced re-approval of gemtuzumab ozogamicin (GO), a CD33-targeting immunoconjugate, for treatment of newly diagnosed and relapsed/refractory acute myeloid leukemia (AML). This is a very significant step toward defining new treatment regimens in AML, as the treatment has essentially stayed unchanged with the '7 + 3 induction regimen' (7 days cytarabine and 3 days of anthracycline) since 1973. GO is the first antibody-drug conjugate to receive FDA approval for treating cancer. This review article discusses the challenges faced and lessons learned during the journey of GO for AML treatment. Selected trials that have made significant contribution in our understanding of the most efficacious and safe use of GO for treating AML patients as well as factors influencing GO response are highlighted in this article.

Flai (fludarabine, cytarabine, idarubicin) plus low-dose Gemtuzumab Ozogamicin as induction therapy in CD33-positive AML: Final results and long term outcome of a phase II multicenter clinical trial

The aim of this prospective clinical trial was to evaluate the efficacy and safety of a combination of Gemtuzumab-Ozogamicin (GO) and FLAI scheme (fludarabine, cytarabine, idarubicin) as a first-line therapy in CD33 positive AML. We treated 130 patients, aged <65, with a median age of 52 years. FLAI-GO induction regimen included fludarabine (30 mg/sqm) and cytarabine (2 g/sqm) on days 1-5; idarubicin (10 mg/sqm) on days 1, 3, and 5; and GO (3 mg/sqm) on day 6. SCT was planned for all high-risk AML patients, after consolidation with intermediate doses of cytarabine and idarubicin and a high dose of cytarabine. CD33 expression exceeded 20% in all cases. Primary endpoints of the study included feasibility, overall response rate (ORR) and toxicity. Secondary endpoints included the evaluation of MRD by WT1 expression, feasibility and outcome of consolidation with SCT, overall survival (OS) and disease-free survival (DFS). After induction with FLAI-GO, complete remission (CR) rate was 82%. Four patients achieved partial remission (PR) and 12% were resistant (ORR 85%); death during induction (DDI) was 3%. The hematological and extra hematological toxicity of FLAI-GO was manageable; 45% of patients experienced transient and reversible GO infusion related adverse events. In the setting of patients who achieved a cytological CR after FLAI-GO, the mean of WT1 copies dropped from 8337±9936 copies/10⁴ ABL (diagnosis) to 182 ± 436 copies after induction therapy (p = 0.0001) showing a very good disease debulking. After a median follow-up of 54 months, 67/130 (52%) patients were alive. The probability of 1, 2, and 5-year OS was 80%, 63%, and 52%, respectively. The probability of 1, 2, and 5-year DFS was 77%, 58%, and 52%, respectively. Allogeneic and autologous SCT was performed in 60 (46%) and 23 (18%) patients, respectively. In summary, the final results of this trial confirm that FLAI-GO is an active and safe treatment strategy for CD33-positive AML patients aged ≤ 65 years, allowing a high ORR, a good disease debulking, favorable safety profile, low DDI, and subsequent high SCT rate. The encouraging results of this trial, consolidated by a long follow-up, support the reintroduction of GO in clinical practice.

Impact of marital status during diagnosis on cancer-caused specific survival in acute myeloid leukemia patients: a case-control and population-based study

Objective

This study investigated the impact of marital status on cancer-caused specific mortality among acute myeloid leukemia (AML) patients in the United States.

Methods

We used the Surveillance, Epidemiology and End Results program to identify 50,825 patients who had their clinical and follow-up information available and were diagnosed for AML between the years 1988 and 2015. The univariate and multivariable Cox regression models were used to analyze the patient data, and to minimize the group differences due to covariates between groups, a 1:1 propensity score matching was used in subsequent subgroup analysis.

Results

Our study demonstrated that married patients were less likely to die due to AML after adjusting for demographic and clinicopathological variables, than patients with variable unmarried status. Further analysis indicated that widowed, divorced and never married status correlated with poor cancer-cause specific survival than being married in almost all subgroups after being adjusted for the aforementioned variables (P<0.05). However, the difference between married and separated was not apparent. Moreover, similar survival analysis results were also observed in the 1:1 matched subgroups of marital status, but they displayed varied prognostic factors between them. The association of survival benefit with marriage in AML was consistent with the published survival benefit of conventional therapeutic approaches.

Conclusion

Overall, our study concluded that unmarried AML patients were at greater risk of cancer-specific mortality than married, and thus indicated that physicians should focus on health care strategies that target social support, in order to reduce the cancer-specific mortality in unmarried patients.

Antibody-Drug Conjugates: A Clinical Pharmacy Perspective on an Emerging Cancer Therapy

Antibody-drug conjugates (ADCs) combine highly specific monoclonal antibodies with potent cytotoxic drugs. Their synergy allows for targeted delivery of toxic drugs to cancer cells while sparing systemic exposure. In this review, we focus on the history and clinical applications of ADCs approved by the U.S. Food and Drug Administration (FDA) for the treatment of cancer and highlight new ADCs in the drug development pipeline. Three ADCs have received FDA approval thus far. Gemtuzumab ozogamicin, although withdrawn from the U.S. market, may still be an effective treatment modality in subsets of patients with acute myeloid leukemia. Brentuximab vedotin and ado-trastuzumab emtansine have shown improved efficacy and safety data compared with standard chemotherapy for the treatment of advanced lymphoma and breast cancer, respectively. With a number of ADCs with promising preliminary data in the clinical trial pipeline, cancer therapy is moving forward from traditional chemotherapy to targeted treatment modalities driven by the specificity of monoclonal antibodies and advancing biotechnology.

Association between early promoter-specific DNA methylation changes and outcome in older acute myeloid leukemia patients

Treatment options for older patients with acute myeloid leukemia (AML) range from supportive care alone to full-dose chemotherapy. Identifying factors that predict response to therapy may help increase efficacy and avoid toxicity. The phase II SWOG S0703 study investigated the use of hydroxyurea and azacitidine with gemtuzumab ozogamicin in the elderly AML population and found survival rates similar to those expected with standard AML regimens, with less toxicity. As part of this study, global DNA methylation along with promoter DNA methylation and expression analysis of six candidate genes (CDKN2A, CDKN2B, HIC1, RARB, CDH1 and APAF1) were determined before and during therapy to investigate whether very early changes are prognostic for clinical response. Global DNA methylation was not associated with a clinical response. Samples after 3 or 4 days of treatment with azacitidine showed significantly decreased CDKN2A promoter DNA methylation in patients achieving complete remission (CR) compared to those who did not. Samples from day 7 of treatment showed significantly decreased RARB, CDKN2B and CDH1 promoter DNA methylation in responders compared to nonresponders. Gene-specific DNA methylation analysis of peripheral blood samples may help early identification of those older AML patients most likely to benefit from demethylating agent therapy.

Immunotherapy in acute myeloid leukemia

Despite the remarkable progress made in some leukemias such as CML and CLL, cytotoxic treatment for AML remains essentially unchanged over the last 4 decades. Several lines of evidence, including the graft versus leukemia effect associated with allogeneic hematopoietic stem cell transplantation (HSCT), suggest that immunotherapy is an active modality in AML. Given the lack of progress for chemotherapy in this disease, many novel immunologic treatment approaches have been explored. The goals of non-transplant-based immune approaches have largely consisted of the stimulation or restoration of endogenous immune responses or the targeting of specific tumor antigens by immune cells. These strategies have been associated with less toxicity than allogeneic HSCT but typically have inferior efficacy. Allogeneic HSCT exploits major and minor histocompatibility differences between the donor and recipient in order to recognize and eradicate malignancy. With the recognition that the immune system itself provides a basis for treating AML, immunotherapy continues to be an attractive modality to exploit in the treatment of this disease.

Induction chemotherapy with concurrent chemoradiotherapy versus concurrent chemoradiotherapy for locally advanced squamous cell carcinoma of head and neck: a meta-analysis

Concurrent chemoradiotherapy (CCRT) has been considered to be the standard of care for locally advanced squamous cell carcinoma of head and neck (LA-SCCHN). Whether induction chemotherapy (IC) with CCRT will further improve the clinical outcomes or not is still unclear. We conducted a meta-analysis to compare the two regimens for LA-SCCHN. Literature searches were carried out in PubMed, Embase, Cochrane Library and Chinese Biology Medicine from inception to November 2014. Five prospective randomized controlled trials (RCTs) with 922 patients were included in meta-analysis. Results were expressed as hazard ratios (HRs) or relative risks (RRs) with 95% confidence intervals (CIs). Compared with CCRT, IC with CCRT showed no statistically significant differences in overall survival (OS), progression-free survival (PFS), overall response rate (ORR) or locoregional recurrence rate (LRR), but could increase risks of grade 3-4 febrile neutropenia (P = 0.0009) and leukopenia (P = 0.04). In contrast, distant metastasis rate (DMR) decreased (P = 0.006) and complete response rate (CR) improved (P = 0.010) for IC with CCRT. In conclusion, the current studies do not support the use of IC with CCRT over CCRT, and the further positioning of IC with CCRT as standard treatment for LA-SCCHN will come from more RCTs directly comparing IC followed by CCRT with CCRT.

Mylotarg has potent anti-leukaemic effect: a systematic review and meta-analysis of anti-CD33 antibody treatment in acute myeloid leukaemia

Conventional chemotherapy is ineffective in the majority of patients with acute myeloid leukaemia (AML), and monoclonal antibodies recognising CD33 expressed on myeloid progenitors (e.g. gemtuzumab ozogamicin (GO)) have been reported to improve outcome in patients with AML. Reports of excess toxicity have resulted in GO's licence being withdrawn. As a result, the role of these agents remains unclear. A systematic review and meta-analysis included studies of patients with AML who had entered a randomised control trial (RCT), where one arm included anti-CD33 antibody therapy. Fixed effect meta-analysis was used, involving calculation of observed minus expected number of events, and variance for each endpoint in each trial, with the overall treatment effect expressed as Peto's odds ratio with 95 % confidence interval. Meta-analysis of 11 RCTs with 13 randomisations involving GO was undertaken. Although GO increased induction deaths (p = 0.02), it led to a reduction in resistant disease (p = 0.0009); hence, there was no improvement in complete remission. Whilst GO improved relapse-free survival (hazard ratio (HR) = 0.90, 95 % confidence interval (CI) = 0.84-0.98, p = 0.01), there was no overall benefit of GO in overall survival (OS) (HR = 0.96, 95 % CI = 0.90-1.02, p = 0.2). GO improved OS in patients with favourable cytogenetics, with no evidence of benefit in patients with intermediate or adverse cytogenetics (test for heterogeneity between subtotals p = 0.01). GO has a potent clinically detectable anti-leukaemic effect. Further trials to investigate its optimum delivery and identification of patient populations who may benefit are needed.

Anti-CD33 chimeric antigen receptor targeting of acute myeloid leukemia

Current therapies for acute myeloid leukemia are associated with high failure and relapse rates. Adoptive immunotherapies, which have shown promise in the treatment of hematologic malignancies, have the potential to target acute myeloid leukemia through pathways that are distinct and complementary to current approaches. Here, we describe the development of a novel adoptive immunotherapy specific for this disease. We generated a second generation CD33-specific chimeric antigen receptor capable of redirecting cytolytic effector T cells against leukemic cells. CD33 is expressed in approximately 90% of acute myeloid leukemia cases and has demonstrated utility as a target of therapeutic antibodies. Chimeric antigen receptor-modified T cells efficiently killed leukemia cell lines and primary tumor cells in vitro. The anti-leukemia effect was CD33-specific, mediated through T-cell effector functions, and displayed tumor lysis at effector:target ratios as low as 1:20. Furthermore, the CD33-redirected T cells were effective in vivo, preventing the development of leukemia after prophylactic administration and delaying the progression of established disease in mice. These data provide pre-clinical validation of the effectiveness of a second-generation anti-CD33 chimeric antigen receptor therapy for acute myeloid leukemia, and support its continued development as a clinical therapeutic.

Advances in treating acute myeloid leukemia

Acute myeloid leukemia (AML) arises within the bone marrow from a malignant hematopoietic progenitor cell. Though AML is still often fatal, cure rates overall continue to improve incrementally yet steadily, primarily for two reasons: first, insights into the pathogenesis of AML over the last several decades have led to the development of a relatively sophisticated classification scheme that allows more nuanced risk stratification to guide treatment choices; second, improvements in stem cell transplantation have allowed many more patients to take advantage of this highly effective therapeutic technique. Improvements in overall survival for patients with AML are expected to continue rising because of the anticipated introduction of targeted therapies into this treatment platform.

Inching toward cure of acute myeloid leukemia: a summary of the progress made in the last 50 years

Despite some claims to the contrary, I believe substantial progress has been made in the last half century toward cure of acute myeloid leukemia in children and adults. The tried and true mechanism for this progress has been clinical trial and error. This method has been supplemented with an ever-increasing amount of work at the clinical laboratory interface that is beginning to allow us to develop specific therapy for afflicted individuals. This review details where we stand today and how we got here.

Addition of gemtuzumab ozogamicin to induction chemotherapy in adult patients with acute myeloid leukaemia: a meta-analysis of individual patient data from randomised controlled trials

BACKGROUND

Gemtuzumab ozogamicin was the first example of antibody-directed chemotherapy in cancer, and was developed for acute myeloid leukaemia. However, randomised trials in which it was combined with standard induction chemotherapy in adults have produced conflicting results. We did a meta-analysis of individual patient data to assess the efficacy of adding gemtuzumab ozogamicin to induction chemotherapy in adult patients with acute myeloid leukaemia.

METHODS

We searched PubMed for reports of randomised controlled trials published in any language up to May 1, 2013, that included an assessment of gemtuzumab ozogamicin given to adults (aged 15 years and older) in conjunction with the first course of intensive induction chemotherapy for acute myeloid leukaemia (excluding acute promyelocytic leukaemia) compared with chemotherapy alone. Published data were supplemented with additional data obtained by contacting individual trialists. The primary endpoint of interest was overall survival. We used standard meta-analytic techniques, with an assumption-free (or fixed-effect) method. We also did exploratory stratified analyses to investigate whether any baseline features predicted a greater or lesser benefit from gemtuzumab ozogamicin.

FINDINGS

We obtained data from five randomised controlled trials (3325 patients); all trials were centrally randomised and open label, with overall survival as the primary endpoint. The addition of gemtuzumab ozogamicin did not increase the proportion of patients achieving complete remission with or without complete peripheral count recovery (odds ratio [OR] 0·91, 95% CI 0·77-1·07; p=0·3). However, the addition of gemtuzumab ozogamicin significantly reduced the risk of relapse (OR 0·81, 0·73-0·90; p=0·0001), and improved overall survival at 5 years (OR 0·90, 0·82-0·98; p=0·01). At 6 years, the absolute survival benefit was especially apparent in patients with favourable cytogenetic characteristics (20·7%; OR 0·47, 0·31-0·73; p=0·0006), but was also seen in those with intermediate characteristics (5·7%; OR 0·84, 0·75-0·95; p=0·005). Patients with adverse cytogenetic characteristics did not benefit (2·2%; OR 0·99, 0·83-1·18; p=0·9). Doses of 3 mg/m(2) were associated with fewer early deaths than doses of 6 mg/m(2), with equal efficacy.

INTERPRETATION

Gemtuzumab ozogamicin can be safely added to conventional induction therapy and provides a significant survival benefit for patients without adverse cytogenetic characteristics. These data suggest that the use of gemtuzumab ozogamicin should be reassessed and its licence status might need to be reviewed.

FUNDING

None.

How I treat paediatric relapsed acute myeloid leukaemia

The prognosis of paediatric acute myeloid leukaemia (AML) has improved significantly over the recent decades, but still about one-third of patients relapse. These patients have a relatively poor prognosis, with a probability of long-term survival from relapse of about 35%. This can only be achieved with very intensive chemotherapy and, usually, allogeneic stem cell transplantation, leading to very significant toxicity and even treatment-related mortality. Major improvements in the treatment of paediatric relapsed AML thus are required still, and several possibilities are discussed. In case of a suspected relapse, a comprehensive diagnostic work-up has to be undertaken, because significant changes in the biological features of the AML cells may have occurred between initial diagnosis and relapse. This review discusses many practical issues that one encounters in the treatment of children with relapsed AML. It will also be of interest for those involved in translational research in AML.