CPX-351 in acute myeloid leukemia: can a new formulation maximize the efficacy of old compounds?

Synchronized Codelivery of Combination Chemotherapies Intratumorally Using a Lipidic Lyotropic Liquid Crystal System

In this work, an injectable in situ depot-forming lipidic lyotropic liquid crystal (L3C) system is developed to codeliver a precisely synchronized combination of chemotherapeutics intratumorally. The developed L3C system is composed of amphiphilic lipids and surfactants, including monoolein, phosphatidylcholine, tocopherol acetate, and d-α-tocopherol polyethylene glycol 1000 succinate. Owing to its amphiphilic nature, the developed formulation can coaccommodate both hydrophobic and hydrophilic chemotherapeutic moieties simultaneously. The study presents a proof of concept by designing a combination chemotherapy regimen in vitro and demonstrating its in vivo translation using doxorubicin and paclitaxel as model hydrophilic and hydrophobic drug moieties, respectively. The synchronized combination of the two chemotherapeutics with maximum synergistic activity was identified, coloaded in the developed L3C system at predefined stoichiometric ratios, and evaluated for antitumor efficacy in the 4T1 breast tumor model in BALB/c mice. The drug-loaded L3C formulation is a low-viscosity injectable fluid with a lamellar phase that transforms into a hexagonal mesophase depot system upon intratumoral injection. The drug-loaded depot system locally provides sustained intratumoral delivery of the chemotherapeutics combination at their precisely synchronized ratio for over a period of one month. Results demonstrate that the exposure of the tumor to the precisely synchronized intratumoral chemotherapeutics combination via the developed L3C system resulted in significantly higher antitumor activity and reduced cardiotoxicity compared to the unsynchronized combination chemotherapy or the synchronized but uncoordinated drug delivery administered by a conventional intravenous route. These findings demonstrate the potential of the developed L3C system for achieving synchronized codelivery of the chemotherapeutics combination intratumorally and improving the efficacy of combination chemotherapy.

Smart nanoparticles for cancer therapy

Smart nanoparticles, which can respond to biological cues or be guided by them, are emerging as a promising drug delivery platform for precise cancer treatment. The field of oncology, nanotechnology, and biomedicine has witnessed rapid progress, leading to innovative developments in smart nanoparticles for safer and more effective cancer therapy. In this review, we will highlight recent advancements in smart nanoparticles, including polymeric nanoparticles, dendrimers, micelles, liposomes, protein nanoparticles, cell membrane nanoparticles, mesoporous silica nanoparticles, gold nanoparticles, iron oxide nanoparticles, quantum dots, carbon nanotubes, black phosphorus, MOF nanoparticles, and others. We will focus on their classification, structures, synthesis, and intelligent features. These smart nanoparticles possess the ability to respond to various external and internal stimuli, such as enzymes, pH, temperature, optics, and magnetism, making them intelligent systems. Additionally, this review will explore the latest studies on tumor targeting by functionalizing the surfaces of smart nanoparticles with tumor-specific ligands like antibodies, peptides, transferrin, and folic acid. We will also summarize different types of drug delivery options, including small molecules, peptides, proteins, nucleic acids, and even living cells, for their potential use in cancer therapy. While the potential of smart nanoparticles is promising, we will also acknowledge the challenges and clinical prospects associated with their use. Finally, we will propose a blueprint that involves the use of artificial intelligence-powered nanoparticles in cancer treatment applications. By harnessing the potential of smart nanoparticles, this review aims to usher in a new era of precise and personalized cancer therapy, providing patients with individualized treatment options.

Oncology stewardship in acute myeloid leukemia

In recent years, an explosion of novel agents has shifted the treatment paradigm for patients with acute myeloid leukemia. The optimal place in therapy for many of these novel agents remains unknown due to limited guidance from national guidelines and the way these agents were studied prior to entering the market. A critical evaluation of the literature and incorporation of oncology stewardship principles can be helpful in determining an optimal place for these agents while being mindful of the overall cost that is associated with therapies. The purpose of this review is to critically evaluate the efficacy and safety data for five controversial agents and provide examples of the use of stewardship practices in determining their place in the treatment of acute myeloid leukemia.

Can the New and Old Drugs Exert an Immunomodulatory Effect in Acute Myeloid Leukemia?

Simple Summary

The advent of novel immunotherapeutic strategies has revealed the importance of immune dysregulation and of a tolerogenic microenvironment for acute myeloid leukemia (AML) fitness. We reviewed the “off-target” effects on the immune system of different drugs used in the treatment of AML to explore the advantages of this unexpected interaction.

Abstract

Acute myeloid leukemia (AML) is considered an immune-suppressive neoplasm capable of evading immune surveillance through cellular and environmental players. Increasing knowledge of the immune system (IS) status at diagnosis seems to suggest ever more attention of the crosstalk between the leukemic clone and its immunologic counterpart. During the last years, the advent of novel immunotherapeutic strategies has revealed the importance of immune dysregulation and suppression for leukemia fitness. Considering all these premises, we reviewed the “off-target” effects on the IS of different drugs used in the treatment of AML, focusing on the main advantages of this interaction. The data reported support the idea that a successful therapeutic strategy should consider tailored approaches for performing leukemia eradication by both direct blasts killing and the engagement of the IS.

How to address second and therapy-related acute myelogenous leukaemia

Secondary acute myelogenous leukaemia (AML), as compared to de novo AML, occurs in the more elderly population, is independently more resistant to cytotoxic chemotherapy, has a higher relapse rate, and a worse prognosis. Secondary AML (sAML) is a heterogeneous disease, both biologically and clinically, even within the World Health Organization subgroups of sAML. Outcomes are the poorest in subgroups with sAML arising from an antecedent haematologic disorder which has been previously treated (ts-AML), and sAML in patients <55 years of age. This review describes the suboptimal outcomes of contemporary therapy, to support the notion of an unmet need for innovative treatment strategies in sAML. Despite the recent approval of CPX-351, long-term outcomes for this high-risk disease remain dismal. Resistance mechanisms to intensive chemotherapy contribute to relapse. Targeted immune therapy may avoid multidrug resistance mechanisms, but are unlikely to provide long-term remission due to a complex and rapidly evolving clonal disease profile. Advances for sAML will likely be accomplished by CAR T cell therapy or bispecific antibodies providing a bridge to allogeneic stem cell transplantation. Therefore, focus should be placed on novel strategies that can augment the untargeted effector function of allogeneic grafts.

Tumor in 3D: In Vitro Complex Cellular Models to Improve Nanodrugs Cancer Therapy

Nanodrugs represent novel solutions to reshuffle repurposed drugs for cancer therapy. They might offer different therapeutic options by combining targeted drug delivery and imaging in unique platforms. Such nanomaterials are deemed to overcome the limitations of currently available treatments, ultimately improving patients' life quality. However, despite these promises being made for over three decades, the poor clinical translation of nanoparticle- based therapies calls for deeper in vit.. and in vivo investigations. Translational issues arise very early during the development of nanodrugs, where complex and more reliable cell models are often replaced by easily accessible and convenient 2D monocultures. This is particularly true in the field of cancer therapy. In fact, 2D monocultures provide poor information about the real impact of the nanodrugs in a complex living organism, especially given the poor mimicry of the solid Tumors Microenvironment (TME). The dense and complex extracellular matrix (ECM) of solid tumors dramatically restricts nanoparticles efficacy, impairing the successful implementation of nanodrugs in medical applications. Herein, we propose a comprehensive guideline of the 3D cell culture models currently available, including their potential and limitations for the evaluation of nanodrugs activity. Advanced culture techniques, more closely resembling the physiological conditions of the TME, might give a better prediction of the reciprocal interactions between cells and nanoparticles and eventually help reconsider the use of old drugs for new applications.

Liposomal encapsulated cytarabine and daunorubicin (CPX-351) for older patients with acute myeloid leukemia

Acute myeloid leukemia (AML) is a heterogenous disease that predominantly affects older adults. Despite recent advances in therapy, outcomes for AML with conventional induction chemotherapy are worse with advanced age. CPX-351 is a liposomal encapsulated formulation of cytarabine and daunorubicin in a 5:1 molar ratio that has been demonstrated to deliver synergistic ratiometric dosing of these drugs in pre-clinical studies. Early phase studies noted the encapsulated formulation of CPX-351 led to the extended duration of detectable cytarabine and daunorubicin levels compared to conventional chemotherapy, which may contribute to prolonged cytopenias. Further clinical trials demonstrated the safety and efficacy of CPX-351 in older adults, particularly those with secondary AML (sAML). The treatment landscape of AML is evolving with the recent approval of multiple therapeutic agents. Further studies are indicated to evaluate the role of CPX-351 potentially in combination with other targeted drugs.

Recent Advances in Use of Topoisomerase Inhibitors in Combination Cancer Therapy

Inhibitors targeting human topoisomerase I and topoisomerase II alpha have provided a useful chemotherapy option for the treatment of many patients suffering from a variety of cancers. While the treatment can be effective in many patient cases, use of these human topoisomerase inhibitors is limited by side-effects that can be severe. A strategy of employing the topoisomerase inhibitors in combination with other treatments can potentially sensitize the cancer to increase the therapeutic efficacy and reduce resistance or adverse side effects. The combination strategies reviewed here include inhibitors of DNA repair, epigenetic modifications, signaling modulators and immunotherapy. The ongoing investigations on cellular response to topoisomerase inhibitors and newly initiated clinical trials may lead to adoption of novel cancer therapy regimens that can effectively stop the proliferation of cancer cells while limiting the development of resistance.

Health state utilities associated with treatment options for acute myeloid leukemia (AML)

Aims: Acute myeloid leukemia (AML) treatment typically involves remission induction chemotherapy followed by consolidation chemotherapy. New treatments for AML have recently been introduced, including a chemotherapy formulation called CPX-351, which is administered via less time-intensive IV infusion than the standard "7 + 3" continuous infusion regimen of cytarabine plus an anthracycline. The purpose of this study was to estimate utilities that could be used in economic modeling of AML treatment. Materials and methods: In time trade-off interviews, participants from the UK general population valued 12 health states drafted based on literature and clinician interviews. To identify disutility associated with chemotherapy, two types of induction and four types of consolidation were added to an otherwise identical health state describing AML. The decrease in utility when adding these chemotherapy regimens represents the disutility of each regimen. Five additional health states were valued to estimate utilities associated with other AML treatments. Results: Two hundred participants completed interviews. Mean (SD) utilities were 0.55 (0.31) for pre-treatment AML and 0.66 (0.29) for AML in temporary remission. Adding any chemotherapy significantly decreased utility (p < 0.0001). Induction had a mean disutility of -0.11 with CPX-351 and -0.15 with 7 + 3. Mean disutility for consolidation ranged from -0.03 with outpatient CPX-351 to -0.11 with inpatient 5 + 2. Utilities are also reported for other AML treatments (e.g. transplant, low-intensity chemotherapy). Limitations: One limitation is that the differences in adverse event profiles between the treatment regimens were based on clinician opinion. Future use of CPX-351 in clinical trials or clinical settings will provide additional information on its adverse event profile. Conclusions: While all chemotherapy regimens were associated with disutility, regimens with shorter hospitalization and less time-intensive infusion were generally perceived as preferable. These utilities may be useful in cost-utility models comparing the value of AML treatments.

Blast Transformation in Myeloproliferative Neoplasms: Risk Factors, Biological Findings, and Targeted Therapeutic Options

Myeloproliferative neoplasms represent a heterogenous group of disorders of the hematopoietic stem cell, with an intrinsic risk of evolution into acute myeloid leukemia. The frequency of leukemic evolution varies according to myeloproliferative neoplasms subtype. It is highest in primary myelofibrosis, where it is estimated to be approximately 10–20% at 10 years, following by polycythemia vera, with a risk of 2.3% at 10 years and 7.9% at 20 years. In essential thrombocythemia, however, transformation to acute myeloid leukemia is considered relatively uncommon. Different factors are associated with leukemic evolution in myeloproliferative neoplasms, but generally include advanced age, leukocytosis, exposure to myelosuppressive therapy, cytogenetic abnormalities, as well as increased number of mutations in genes associated with myeloid neoplasms. The prognosis of these patients is dismal, with a medium overall survival ranging from 2.6–7.0 months. Currently, there is no standard of care for managing the blast phase of these diseases, and no treatment to date has consistently led to prolonged survival and/or hematological remission apart from an allogeneic stem cell transplant. Nevertheless, new targeted agents are currently under development. In this review, we present the current evidence regarding risk factors, molecular characterization, and treatment options for this critical subset of myeloproliferative neoplasms patients.

Treatment of MDS

The heterogeneous nature of myelodysplastic syndromes (MDS) demands a complex and personalized variety of therapeutic approaches. Among them, allogeneic hematopoietic stem cell transplantation remains the only potentially curative option and is accessible to only a small number of fit patients. For the majority of patients with MDS, treatment strategies are nonintensive and risk-adapted (by the revised version of the International Prognostic Scoring System), ranging from iron chelation and growth factors to lenalidomide and hypomethylating agents. These approaches are noncurative and aimed instead at improving cytopenias and quality of life and delaying disease progression. These limitations underpin the need for more translational research-based clinical trials in well-defined subgroups of patients with MDS. Indeed, much progress has been made over the past decade in understanding the complex molecular mechanisms underlying MDS. Unfortunately, this has not yet translated into approval of novel treatment options. There is a particularly urgent medical need in patients failing current first-line therapies, such as with erythropoiesis-stimulating or hypomethylating agents. Nevertheless, actual developments are expected to pave the way for exciting novel therapeutic opportunities. This review provides an overview of the current therapeutic landscape in MDS focusing on recent advances in clinical and translational research.

The leukemia strikes back: a review of pathogenesis and treatment of secondary AML

Secondary AML is associated with a disproportionately poor prognosis, consistently shown to exhibit inferior response rates, event-free survival, and overall survival in comparison with de novo AML. Secondary AML may arise from the evolution of an antecedent hematologic disorder, or it may arise as a complication of prior cytotoxic chemotherapy or radiation therapy in the case of therapy-related AML. Because of the high frequency of poor-risk cytogenetics and high-risk molecular features, such as alterations in TP53, leukemic clones are often inherently chemoresistant. Standard of care induction had long remained conventional 7 + 3 until its reformulation as CPX-351, recently FDA approved specifically for secondary AML. However, recent data also suggests relatively favorable outcomes with regimens based on high-dose cytarabine or hypomethylating agents. With several investigational agents being studied, the therapeutic landscape becomes even more complex, and the treatment approach involves patient-specific, disease-specific, and therapy-specific considerations.

Drug delivery systems for elemene, its main active ingredient β-elemene, and its derivatives in cancer therapy

β-elemene is a noncytotoxic Class II antitumor drug extracted from the traditional Chinese medicine Curcuma wenyujin Y. H. Chen et C. Ling. β-elemene exerts its effects by inhibiting cell proliferation, arresting the cell cycle, inducing cell apoptosis, exerting antiangiogenesis and antimetastasis effects, reversing multiple-drug resistance (MDR), and enhancing the immune system. Elemene injection and oral emulsion have been used to treat various tumors, including cancer of the lung, liver, brain, breast, ovary, gastric, prostate, and other tissues, for >20 years. The safety of both elemene injection and oral emulsion in the clinic has been discussed. Recently, the secondary development of β-elemene has attracted the attention of researchers and made great progress. On the one hand, studies have been carried out on liposome-based systems (including solid lipid nanoparticles [SLNs], nanostructured lipid carriers [NLCs], long-circulating liposomes, active targeting liposomes, and multidrug-loaded liposomes) and emulsion systems (including microemulsions, self-emulsion drug delivery systems [SEDDSs], and active targeting microemulsion) to solve the issues of poor solubility in water, low bioavailability, and severe phlebitis, as well as to improve antitumor efficacy. The pharmacokinetics of different drug delivery systems of β-elemene are also summarized. On the other hand, a number of highly active anticancer β-elemene derivatives have been obtained through modification of the structure of β-elemene. This review focuses on the two drug delivery systems and derivatives of β-elemene for cancer therapy.

CPX-351 exhibits hENT-independent uptake and can be potentiated by fludarabine in leukaemic cells lines and primary refractory AML

CPX-351, a liposomal formulation co-encapsulating cytarabine and daunorubicin (DNR) in a synergistic 5:1 M ratio, has shown favourable response in newly diagnosed elderly high-risk AML. This study assessed intracellular ara-CTP levels following in vitro exposure of human immortalised leukaemic cell lines and primary AML blasts to CPX-351, and investigated fludarabine potentiation of intracellular ara-CTP formation from CPX-351. Comparison of intracellular handling of CPX-351 to cytarabine in HL-60 cells indicated slower conversion to ara-CTP for CPX-351, but equivalent cytotoxicity to cytarabine and combined DNR/cytarabine (DA) at 48 h, mostly likely reflecting the need for intracellular liposome processing to release encapsulated drugs. Further assessment demonstrated cytotoxicity of CPX-351 to be superior to DA at 48 and 72 h in cytarabine-resistant THP-1 cells (p < 0.001), and this effect could not be inhibited upon blockade of human equilibrative nucleoside transporter (hENT) function with dipyridamole. Assessment of Flu-CPX in primary blasts from presentation AML patients (n = 5) demonstrated a more rapid and pronounced potentiation of ara-CTP from CPX-351 than in immortalised cell lines, with 4/5 patients showing significant increases in ara-CTP, notably for those that went on to fail induction and relapse treatment in vivo (n = 3). This suggests a favourable impact on patient outcome from Flu-CPX.

An Anti-CLL-1 Antibody-Drug Conjugate for the Treatment of Acute Myeloid Leukemia

PURPOSE

The treatment of acute myeloid leukemia (AML) has not significantly changed in 40 years. Cytarabine- and anthracycline-based chemotherapy induction regimens (7 + 3) remain the standard of care, and most patients have poor long-term survival. The reapproval of Mylotarg, an anti-CD33-calicheamicin antibody-drug conjugate (ADC), has demonstrated ADCs as a clinically validated option to enhance the effectiveness of induction therapy. We are interested in developing a next-generation ADC for AML to improve upon the initial success of Mylotarg.

EXPERIMENTAL DESIGN

The expression pattern of CLL-1 and its hematopoietic potential were investigated. A novel anti-CLL-1-ADC, with a highly potent pyrrolobenzodiazepine (PBD) dimer conjugated through a self-immolative disulfide linker, was developed. The efficacy and safety profiles of this ADC were evaluated in mouse xenograft models and in cynomolgus monkeys.

RESULTS

We demonstrate that CLL-1 shares similar prevalence and trafficking properties that make CD33 an excellent ADC target for AML, but lacks expression on hematopoietic stem cells that hampers current CD33-targeted ADCs. Our anti-CLL-1-ADC is highly effective at depleting tumor cells in AML xenograft models and lacks target independent toxicities at doses that depleted target monocytes and neutrophils in cynomolgus monkeys.

CONCLUSIONS

Collectively, our data suggest that an anti-CLL-1-ADC has the potential to become an effective and safer treatment for AML in humans, by reducing and allowing for faster recovery from initial cytopenias than the current generation of ADCs for AML.