Fractionated doses of gemtuzumab ozogamicin combined with 3 + 7 induction chemotherapy as salvage treatment for young patients with acute myeloid leukemia in first relapse

Gemtuzumab ozogamicin for relapsed or primary refractory acute myeloid leukemia in children-the Polish Pediatric Leukemia and Lymphoma Study Group experience

Background

Gemtuzumab ozogamicin (GO), one of the first targeted drugs used in oncology, consists of an anti-cluster of differentiation 33 (CD33) monoclonal antibody bound to a derivative of cytotoxic calicheamicin. After the drug withdrawn in 2010 due to a significantly higher rate of early deaths, GO regained approval in 2017 for the treatment of newly diagnosed, refractory, or relapsed acute myeloid leukemia (AML) in adults and children over 15 years of age. The objective of the study was a retrospective analysis of clinical characteristics, treatment outcomes, and GO toxicity profile in children with primary refractory or relapsed (R/R) AML treated in Poland from 2008 to 2022.

Methods

Data were collected through the Polish Registry of Acute Myeloid Leukemia. From January 2008 to December 2022, 35 children with R/R AML were treated with GO in seven centers of the Polish Pediatric Leukemia and Lymphoma Study Group.

Results

Most of the children (30 of 35) received only one GO cycle in combination with various chemotherapy cycles (IDA-FLA, DOXO-FLA, FLA, FLAG, and others). Eighteen children (51%) achieved complete remission (CR), 14 did not respond to treatment, and three progressed. GO therapy was followed by allogeneic hematopoietic stem cell transplantation (allo-HSCT) in 18 children in CR. The 5-year overall survival (OS) after GO therapy was 37.1% ± 8.7% for the total cohort. There was a trend toward a superior outcome in patients with strong expression of CD33 expression (over 50% positive cells) compared with that in patients with lower expression of CD33 (OS, 41.2% ± 11.9% versus 27.8% ± 13.2%; p = 0.5; 5-year event-free survival, 35.4% ± 11.6% versus 25.7% ± 12.3%; p = 0.5, respectively). Children under 15 years have better outcome (OS, 34.9% ± 10.4% versus 30% ± 14.5%, p = 0.3). The most common adverse events were bone marrow aplasia, fever of unknown origin, infections, and elevated liver enzyme elevation. Sinusoidal obstruction syndrome occurred in two children.

Conclusions

The use of GO in severely pretreated children, including those under 15 years of age, with previous failure of AML treatment is a feasible and effective bridging therapy to allo-HSCT with an acceptable toxicity profile.

Therapeutic Targeting of Acute Myeloid Leukemia by Gemtuzumab Ozogamicin

Acute myeloid leukemia (AML) is a complex hematological malignancy characterized by genetic and clinical heterogeneity and high mortality. Despite the recent introduction of novel pharmaceutical agents in hemato-oncology, few advancements have been made in AML for decades. In the last years, the therapeutic options have rapidly changed, with the approval of innovative compounds that provide new opportunities, together with new challenges for clinicians: among them, on 1 September, 2017 the Food and Drug Administration granted approval for Gemtuzumab Ozogamicin (GO) in combination with daunorubicin and cytarabine for the treatment of adult patients affected by newly diagnosed CD33⁺ AML. Benefits of GO-based regimens were also reported in the pre- and post-transplantation settings. Moreover, several biomarkers of GO response have been suggested, including expression of CD33 and multidrug resistance genes, cytogenetic and molecular profiles, minimal residual disease and stemness signatures. Among them, elevated CD33 expression on blast cells and non-adverse cytogenetic or molecular risk represent largely validated predictors of good response.

Safety of gemtuzumab ozogamicin as monotherapy or combination therapy in an expanded-access protocol for patients with relapsed or refractory acute myeloid leukemia

Gemtuzumab ozogamicin (GO) remained available to US clinicians through an open-label expanded-access protocol (NCT02312037) until GO was reapproved. Patients were aged ≥3 months with relapsed/refractory (R/R) acute myeloid leukemia (AML), high-risk myelodysplastic syndrome, or acute promyelocytic leukemia (APL), and had exhausted other treatment options. Three hundred and thirty one patients received GO as monotherapy for R/R AML (n = 139), combination therapy for R/R AML (n = 183), or treatment for R/R APL (n = 9). Corresponding treatment discontinuations occurred in 68, 39, and 33% of patients. All-causality grade 5 AEs occurred in 52, 22, and 22% of patients in the monotherapy, combination, and APL groups, respectively. Corresponding grades 3 and 4 treatment-related AEs were reported in 60, 55 and 78% of patients. Hepatotoxicity occurred in five patients: veno-occlusive disease (n = 4) and drug-induced liver injury (n = 1). GO was generally well tolerated in patients with R/R AML or APL. Most frequent treatment-related grade ≥3 AEs were hematologic AEs.Clinicaltrials.gov identifier: NCT02312037.

The addition of gemtuzumab ozogamicin to chemotherapy in adult patients with acute myeloid leukemia

The treatment of acute myeloid leukaemia has remained largely unchanged for the last 30 years since the advent of combination chemotherapy with cytarabine arabinoside and daunorubicin with remission rates around 70% but with long term survival still only around 40% in young adults. Doses of chemotherapy have been pushed to the limit of toxicity. Gemtuzumab ozogamicin allows additional chemotherapy to be delivered to the leukaemic cells without significantly adding to toxicity since the active agent is coupled to a monoclonal anti-CD33 antibody. It was approved by the FDA in 2000 for the treatment of elderly patients with relapsed CD33 positive AML at a dose of 9mg/m(2) on two days two weeks apart. Almost at once, questions were raised about its safety, with a particular liver signal, and it was voluntarily withdrawn from practice in 2010. Many groups have been examining the role of gemtuzumab ozogamicin in combination with chemotherapy, usually at lower doses than originally recommended, with varying degrees of success and toxicity and gemtuzumab ozogamicin is now entering a period of rehabilitation. Currently it is only commercially available in Japan although it is currently also available in the UK Bloodwise AML18 study.

A phase II study of decitabine and gemtuzumab ozogamicin in newly diagnosed and relapsed acute myeloid leukemia and high-risk myelodysplastic syndrome

Decitabine may open the chromatin structure of leukemia cells making them accessible to the calicheamicin epitope of gemtuzumab ozogamicin (GO). A total of 110 patients (median age 70 years; range 27-89 years) were treated with decitabine and GO in a trial designed on model-based futility to accommodate subject heterogeneity: group 1: relapsed/refractory acute myeloid leukemia (AML) with complete remission duration (CRD) <1 year (N=28, 25%); group 2: relapsed/refractory AML with CRD ⩾1 year (N=5, 5%); group 3: untreated AML unfit for intensive chemotherapy or untreated myelodysplastic syndrome (MDS) or untreated myelofibrosis (MF; N=57, 52%); and group 4: AML evolving from MDS or relapsed/refractory MDS or MF (N=20, 18%). Treatment consisted of decitabine 20 mg/m(2) daily for 5 days and GO 3 mg/m(2) on day 5. Post-induction therapy included five cycles of decitabine+GO followed by decitabine alone. Complete remission (CR)/CR with incomplete count recovery was achieved in 39 (35%) patients; group 1= 5/28 (17%), group 2=3/5 (60%), group 3=24/57 (42%) and group 4=7/20 (35%). The 8-week mortality in groups 3 and 4 was 16% and 10%, respectively. Common drug-related adverse events included nausea, mucositis and hemorrhage. Decitabine and GO improved the response rate but not overall survival compared with historical outcomes in untreated AML ⩾60 years.

Treatment of Acute Myeloid Leukemia in Adolescent and Young Adult Patients

The objectives of this review were to discuss standard and investigational treatment strategies for adolescent and young adult with acute myeloid leukemia, excluding acute promyelocytic leukemia. Acute myeloid leukemia (AML) in adolescent and young adult patients (AYAs) may need a different type of therapy than those currently used in children and older patients. As soon as AML is diagnosed, AYA patient should be offered to participate in well-designed clinical trials. The standard treatment approach for AYAs with AML is remission induction chemotherapy with an anthracycline/cytarabine combination, followed by either consolidation chemotherapy or stem cell transplantation, depending on the ability of the patient to tolerate intensive treatment and cytogenetic features. Presently, continuing progress of novel drugs targeting specific pathways in acute leukemia may bring AML treatment into a new era.

Gemtuzumab ozogamicin in acute myeloid leukemia revisited

INTRODUCTION

Gemtuzumab ozogamicin (GO) is a combination of calicheamicin and a recombinant humanized IgG4 antibody directed against CD33. From 2000 to 2010, it was approved by the FDA for treatment of relapsed, older patients with CD33(+) acute myeloid leukemia (AML). After withdrawal from the market, several trials have provided new evidence on the safety and clinical efficacy of GO.

AREAS COVERED

In this review, we discuss pharmacological and clinical aspects of GO. GO was found to show benefit in AML patients as adjunct to intensive chemotherapy when it was given in parallel to induction therapy. The benefit was restricted to patients with a favorable- or an intermediate-risk cytogenetic profile. Higher doses of GO above 6 mg/m(2) per administration were associated with increased toxicity without survival benefit, whereas repetitive doses of 3 mg/m(2) resulting in cumulative doses of 9 mg/m(2) were well tolerated. Predictive markers for response to GO other than the cytogenetic profile and P-glycoprotein activity are still missing.

EXPERT OPINION

GO as adjunct and in parallel to intensive induction chemotherapy does significantly improve survival end points in AML patients with favorable/intermediate-risk cytogenetics. A dose of 3 mg/m(2) per administration appears safer compared with 6 mg/m(2) and even 9 mg/m(2).

Novel therapies for children with acute myeloid leukaemia

Significant improvements in survival for children with acute myeloid leukaemia (AML) have been made over the past three decades, with overall survival rates now approximately 60-70%. However, these gains can be largely attributed to more intensive use of conventional cytotoxics made possible by advances in supportive care, and although over 90% of children achieve remission with frontline therapy, approximately one third in current protocols relapse. Furthermore, late effects of therapy cause significant morbidity for many survivors. Novel therapies are therefore desperately needed. Early-phase paediatric trials of several new agents such as clofarabine, sorafenib and gemtuzumab ozogamicin have shown encouraging results in recent years. Due to the relatively low incidence of AML in childhood, the success of paediatric early-phase clinical trials is largely dependent upon collaborative clinical trial design by international cooperative study groups. Successfully incorporating novel therapies into frontline therapy remains a challenge, but the potential for significant improvement in the duration and quality of survival for children with AML is high.

Ara-C, Idarubicine and Gentuzumab Ozogamicin (AIM) as Salvage Treatment in Advanced Acute Myeloid Leukemia Patients

Long-term survival of relapsed/refractory acute myeloid leukemia (AML) remains a major problem, particularly in patients not eligible for transplantation.

We hereby evaluated the feasibility and efficacy of adding Gemtuzumab Ozogamicin to salvage chemotherapy (Ara-C, Idarubicine, Peg-Filgrastim) in relapsed/refractory AML. The main endpoints were: the rate of complete remissions (CR) and the proportion of patients capable of undergoing a stem cell transplant.

Fourty-two patients were enrolled. The overall CR rate was 76% and no induction deaths were reported. In 56% of patients, a transplant procedure could be performed. The treatment schedule proved feasible and well tolerated, providing a high CR rate and a useful bridge to transplant.