Real-life experience with CPX-351 and impact on the outcome of high-risk AML patients: a multicentric French cohort

Older Patients with Acute Myeloid Leukemia Deserve Individualized Treatment

PURPOSE OF REVIEW

Treatment of elderly patients with acute myeloid leukemia is a known challenge for hematologists due to patient diversity, heterogeneous disease biology, and a rapidly evolving treatment landscape. Here, we highlight the importance of determining fitness, review the latest therapeutic developments, and discuss clinical scenarios to provide guidance on individualized treatment for older AML patients.

RECENT FINDINGS

Several factors, like age, performance status, and comorbidities, play a role in fitness and are associated with outcome. Comorbidity scoring systems and geriatric assessments are tools to help physicians select the most appropriate treatment for each patient. The addition of venetoclax, targeted therapy with IDH1/2 and FLT3 inhibitors, and enhanced formulas of existing drugs like CPX-351 and oral azacitidine have improved responses and outcomes. New drugs and combination therapies have increased the therapeutic options for elderly AML patients but determination of fitness and disease biology is essential to select patient-tailored treatments.

What to use to treat AML: the role of emerging therapies

The development and approval of novel substances have resulted in substantial improvements in the treatment of acute myeloid leukemia (AML). In the current era of novel treatment options, genetic and molecular testing at the time of diagnosis and relapse becomes increasingly relevant. Midostaurin in combination with intensive chemotherapy is the standard of care as upfront therapy in younger AML patients with mutated fms-related tyrosine kinase 3 (FLT3). Gilteritinib, a second- generation FLT3 inhibitor, represents a key drug for relapsed/refractory (R/R) FLT3-mutated AML patients. Targeted therapy has also been developed for patients with mutated isocitrate dehydrogenase 1 (IDH1) and IDH2. The US Food and Drug Administration (FDA) approved ivosidenib as a monotherapy for newly diagnosed older adult IDH1-mutated patients and enasidenib for R/R IDH2-mutated AML patients. CPX-351, a liposomal formulation of daunorubicin and cytarabine, has become an important upfront treatment strategy for fit patients with therapy-related AML or AML with myelodysplasia-related changes that are generally challenging to treat. The antibody drug conjugate gemtuzumab ozogamicin was approved in combination with intensive therapy for patients with newly diagnosed (FDA/European Medicines Agency [EMA]) as well as R/R CD33+ AML. The combination of venetoclax, an oral selective B-cell leukemia/lymphoma-2 inhibitor, with hypomethylating agents or low-dose AraC (LDAC) has changed the treatment landscape and prognosis for older adult patients very favorably. The addition of glasdegib, a small-molecule hedgehog inhibitor, to LDAC is another example of novel options in older patients. Further substances have shown promising results in early clinical trials.

Evolving Therapeutic Approaches for Older Patients with Acute Myeloid Leukemia in 2021

Simple Summary

The better understanding of disease biology, the availability of new effective drugs and the increased awareness of patients’ heterogeneity in terms of fitness and personal expectations has made the current treatment paradigm of AML in the elderly very challenging. Here, we discuss the evolving criteria used to define eligibility for induction chemotherapy and transplantation, the introduction of new agents in the treatment of patients with very different clinical conditions, the implications of precision medicine and the importance of quality of life and supportive care, proposing a simplified algorithm that we follow in 2021.

Abstract

Acute myeloid leukemia (AML) in older patients is characterized by unfavorable prognosis due to adverse disease features and a high rate of treatment-related complications. Classical therapeutic options range from intensive chemotherapy in fit patients, potentially followed by allogeneic hematopoietic cell transplantation (allo-HCT), to hypomethylating agents or palliative care alone for unfit/frail ones. In the era of precision medicine, the treatment paradigm of AML is rapidly changing. On the one hand, a plethora of new targeted drugs with good tolerability profiles are becoming available, offering the possibility to achieve a prolonged remission to many patients not otherwise eligible for more intensive therapies. On the other hand, better tools to assess patients’ fitness and improvements in the selection and management of those undergoing allo-HCT will hopefully reduce treatment-related mortality and complications. Importantly, a detailed genetic characterization of AML has become of paramount importance to choose the best therapeutic option in both intensively treated and unfit patients. Finally, improving supportive care and quality of life is of major importance in this age group, especially for the minority of patients that are still candidates for palliative care because of very poor clinical conditions or unwillingness to receive active treatments. In the present review, we discuss the evolving approaches in the treatment of older AML patients, which is becoming increasingly challenging following the advent of new effective drugs for a very heterogeneous and complex population.

Real-world experience of CPX-351 as first-line treatment for patients with acute myeloid leukemia

To investigate the efficacy and toxicities of CPX-351 outside a clinical trial, we analyzed 188 patients (median age 65 years, range 26–80) treated for therapy-related acute myeloid leukemia (t-AML, 29%) or AML with myelodysplasia-related changes (AML-MRC, 70%). Eighty-six percent received one, 14% two induction cycles, and 10% received consolidation (representing 22% of patients with CR/CRi) with CPX-351. Following induction, CR/CRi rate was 47% including 64% of patients with available information achieving measurable residual disease (MRD) negativity (<10⁻³) as measured by flow cytometry. After a median follow-up of 9.3 months, median overall survival (OS) was 21 months and 1-year OS rate 64%. In multivariate analysis, complex karyotype predicted lower response (p = 0.0001), while pretreatment with hypomethylating agents (p = 0.02) and adverse European LeukemiaNet 2017 genetic risk (p < 0.0001) were associated with lower OS. Allogeneic hematopoietic cell transplantation (allo-HCT) was performed in 116 patients (62%) resulting in promising outcome (median survival not reached, 1-year OS 73%), especially in MRD-negative patients (p = 0.048). With 69% of patients developing grade III/IV non-hematologic toxicity following induction and a day 30-mortality of 8% the safety profile was consistent with previous findings. These real-world data confirm CPX-351 as efficient treatment for these high-risk AML patients facilitating allo-HCT in many patients with promising outcome after transplantation.

Management and Outcomes of Blast Transformed Chronic Myelomonocytic Leukemia

PURPOSE OF REVIEW

Despite recent advances in the treatment of de novo acute myeloid leukemia (AML), AML arising from antecedent chronic myelomonocytic leukemia (CMML) continues to have dismal outcomes. While the unique biological drivers of CMML and subsequent leukemic transformation (LT) have been revealed with advances in molecular characterization, this has not yet translated to the bedside. Here, we review these biologic drivers, outcomes with current therapies, and rationale avenues of future investigation specifically in blast phase CMML (CMML-BP).

RECENT FINDINGS

CMML-BP outcomes are studied as an aggregate with more common categories of AML with myelodysplasia-related changes (AML-MRCs) or the even broader category of secondary AML (sAML), which illustrates the crux of the problem. While a modest survival advantage with allogeneic hematopoietic stem cell transplant exists, the difficulty is bridging patients to transplant and managing patients that require an allograft-sparing approach. Limited data suggest that short-lived remissions can be obtained employing CPX-351 or venetoclax-based lower intensity combination therapy. Promising future strategies include repurposing cladribine, exploiting the supportive role of dendritic cell subsets with anti-CD123 therapies, MCL-1 inhibition, dual MEK/PLK1 inhibition, FLT3 inhibition in RAS-mutated and CBL-mutated subsets, and immune therapies targeting novel immune checkpoint molecules such as the leukocyte immunoglobulin-like receptor B4 (LILRB4), an immune-modulatory transmembrane protein restrictively expressed on monocytic cells. The successful management of an entity as unique as CMML-BP will require a cooperative, concerted effort to design and conduct clinical trials dedicated to this rare form of sAML.

Molecular Landscape of Therapy-related Myeloid Neoplasms in Patients Previously Treated for Gynecologic and Breast Cancers

Definition of therapy-related myeloid neoplasms (TRMN) is only based on clinical history of exposure to leukemogenic therapy. No specific molecular classification combining therapy-related acute myeloid leukemia and therapy-related myelodysplastic syndromes has been proposed. We aimed to describe the molecular landscape of TRMN at diagnosis, among 77 patients with previous gynecologic and breast cancer with a dedicated next-generation sequencing panel covering 74 genes. We investigated the impact of clonal hematopoiesis of indeterminate potential-associated mutations (CHIP-AMs defined as presence at TRMN stage of mutations described in CHIP with a frequency >1%) on overall survival (OS) and the clinical relevance of a modified genetic ontogeny-based classifier that categorized patients in 3 subgroups. The most frequently mutated genes were TP53 (31%), DNMT3A (19%), IDH1/2 (13%), NRAS (13%), TET2 (12%), NPM1 (10%), PPM1D (9%), and PTPN11 (9%). CHIP-AMs were detected in 66% of TRMN patients, with no impact on OS. Yet, patients with CHIP-AM were older and had a longer time interval between solid tumor diagnosis and TRMN. According to our modified ontogeny-based classifier, we observed that the patients with TP53 or PPM1D mutations had more treatment lines and complex karyotypes, the “MDS-like” patients were older with more gene mutations, while patients with “De novo/pan-AML” mutations were younger with more balanced chromosomal translocations. Median OS within each subgroup was 7.5, 14.5, and 25.2 months, respectively, with statistically significant difference in multivariate analysis. These results support the integration of cytogenetic and molecular markers into the future TRMN classification to reflect the biological diversity of TRMN and its impact on outcomes.

Impact of induction chemotherapy with intermediate-dosed cytarabine and subsequent allogeneic stem cell transplantation on the outcome of high-risk acute myeloid leukemia

Background

Acute myeloid leukemia (AML) with antecedent hematological disease (s-AML) and treatment-related AML (t-AML) predicts poor prognosis. Intensive treatment protocols of those high-risk patients should consider allogeneic stem cell transplantation (allo-HSCT) in first complete remission (CR). Despite allo-HSCT, relapse rate remains high. Induction chemotherapy with liposomal cytarabine and daunorubicin (CPX-351) has been approved for patients with AML with myeloid-related changes (AML-MRC) or t-AML based on improved survival and remission rates compared to standard 7 + 3 induction.

Patients and methods

110 patients with newly diagnosed s-AML or t-AML at a university hospital were analyzed retrospectively. Median age was 62 years (24–77 years). A total of 65 patients with s-AML after MDS (59%) and 23 patients (20.9%) with t-AML were included. Induction chemotherapy consisted of intermediate-dosed cytarabine (ID-AraC) in combination with idarubicin (patients up to 60 years) or mitoxantrone (patients over 60 years). In patients subsequently undergoing allo-HSCT, reduced conditioning regimens (RIC) were applied prior to transplantation in 47 of 62 patients (76%).

Results

Induction chemotherapy with ID-AraC resulted in an overall response rate of 83% including complete remission (CR/CRi) in 69 patients (63%) with a low rate of early death (2.7%). Most relevant non-hematologic toxicity consisted of infectious complications including sepsis with need of intensive care treatment in five patients (4.5%) and proven or probable invasive fungal disease in eight patients (7.2%). Relapse-free survival (RFS), event-free survival (EFS) and overall survival (OS) of the whole cohort were 19 months (0–167), 10 months (0–234) and 15 months (0–234), respectively (p < 0.0001). A significant improvement of OS was observed in patients who underwent allo-HSCT compared to those without subsequent allo-HSCT: 9 vs. 46 months, p < 0.0001. Rate of transplantation-related mortality (TRM) in the early phase post allo-HSCT was low (0.9% at day 30 and 1.8% at day 90, respectively). RIC conditioning results in OS rate of 60% after 60 months post allo-HSCT (median OS not reached).

Conclusion

S-AML and t-AML patients receiving induction chemotherapy with intermediate-dosed cytarabine showed satisfactory response rate and consolidation therapy with allo-HSCT after full or reduced-intensity conditioning further improved survival in these patients with similar outcome as reported for CPX-351.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00432-021-03733-0.

Emerging therapies for AML with myelodysplasia-related changes: slowly but surely moving the needle

Introduction: Patients with acute myeloid leukemia with myelodysplasia-related changes (AML-MRC) have historically poor outcomes with conventional chemotherapy regimens. Current treatment strategies focus on intensive induction therapy followed by allogeneic stem cell transplant or a less intensive approach with hypomethylating agents with or without venetoclax. CPX-351 is a liposomal formulation of cytarabine and daunorubicin that has been shown to significantly improve response rates and survival compared with 7 + 3 (continuous infusion cytarabine plus anthracyclines). Despite the approval of CPX-351 for AML-MRC, overall prognosis remains poor with an unmet need to develop novel therapeutic strategies for this patient population.Areas covered: This article reviews the data for existing therapeutic options for patients with AML-MRC and the emerging therapies undergoing clinical trial development for this patient population.Expert opinion: The development of CPX-351 as a more effective induction therapeutic backbone for patients with AML-MRC presents an opportunity to investigate novel combination regimens in order to further improve outcomes. Promising emerging therapeutic modalities include immunotherapeutic strategies, small-molecule inhibitors and targeted agents. Unfortunately, there have been few clinical trials focusing on patients with AML-MRC with reliance instead on subgroup analyses. Clinical trials focused specifically on this patient population are urgently needed.

Older adults with newly diagnosed high-risk/secondary AML who achieved remission with CPX-351: phase 3 post hoc analyses

CPX-351, a dual-drug liposomal encapsulation of daunorubicin/cytarabine in a synergistic 1:5 molar ratio, is approved for the treatment of adults with newly diagnosed, therapy-related acute myeloid leukemia (t-AML) or AML with myelodysplasia-related changes (AML-MRC). In a pivotal phase 3 study, patients aged 60 to 75 years with newly diagnosed, high-risk/secondary AML were randomized to receive CPX-351 or conventional 7+3 chemotherapy. In the primary endpoint analysis, CPX-351 demonstrated significantly prolonged median overall survival (OS) vs 7+3. These exploratory post hoc subgroup analyses evaluated the impact of achieving complete remission (CR) or CR with incomplete neutrophil or platelet recovery (CRi) with CPX-351 (73/153 [48%]) vs conventional 7+3 (52/56 [33%]) on outcomes. CPX-351 improved median OS vs 7+3 in patients who achieved CR or CRi (25.43 vs 10.41 months; hazard ratio = 0.49; 95% confidence interval, 0.31, 0.77). Improved median OS was seen across AML subtypes (t-AML, AML-MRC), age subgroups (60 to 69 vs 70 to 75 years), patients with prior hypomethylating agent exposure, and patients who did not undergo transplantation. Patients who achieved CR or CRi with CPX-351 also had a higher rate of transplantation, a longer median OS landmarked from the date of transplantation (not reached vs 11.65 months; hazard ratio = 0.43; 95% confidence interval, 0.21, 0.89), and a safety profile that was consistent with the known safety profile of 7+3. These results suggest deeper remissions may be achieved with CPX-351, leading to improved OS. This study was registered at www.clinicaltrials.gov as #NCT01696084.

FLT3 Tyrosine Kinase Inhibitors for the Treatment of Fit and Unfit Patients with FLT3-Mutated AML: A Systematic Review

FLT3-mutated acute myeloid leukemia accounts for around 30% of acute myeloid leukemia (AML). The mutation carried a poor prognosis until the rise of tyrosine kinase inhibitors (TKIs). New potent and specific inhibitors have successfully altered the course of the disease, increasing the complete response rate and the survival of patients with FLT3-mutated AML. The aim of this article is to review all the current knowledge on these game-changing drugs as well as the unsolved issues raised by their use for fit and unfit FLT3-mutated AML patients. To this end, we analyzed the results of phase I, II, III clinical trials evaluating FLT3-TKI both in the first-line, relapse monotherapy or in combination referenced in the PubMed, the American Society of Hematology, the European Hematology Association, and the Clinicaltrials.gov databases, as well as basic science reports on TKI resistance from the same databases. The review follows a chronological presentation of the different trials that allowed the development of first- and second-generation TKI and ends with a review of the current lines of evidence on leukemic blasts resistance mechanisms that allow them to escape TKI.