Safety and Efficacy of Liposomal Cytarabine in the Treatment of Neoplastic Meningitis

An overview of the therapeutic strategies for neoplastic meningitis due to breast cancer: when and why?

INTRODUCTION

Neoplastic meningitis (NM), also known as leptomeningeal carcinomatosis, is characterized by the infiltration of tumor cells into the meninges, and poses a significant therapeutic challenge owing to its aggressive nature and limited treatment options. Breast cancer is a common cause of NM among solid tumors, further highlighting the urgent need to explore effective therapeutic strategies. This review aims to provide insights into the evolving landscape of NM therapy in breast cancer by collating existing research, evaluating current treatments, and identifying potential emerging therapeutic options.

AREAS COVERED

This review explores the clinical features, therapeutic strategies, recent advances, and challenges of managing NM in patients with breast cancer. Its management includes multimodal strategies, including systemic and intrathecal chemotherapy, radiation therapy, and supportive care. This review also emphasizes targeted drug options and optimal drug concentrations, and discusses emerging therapies. Additionally, it highlights the variability in treatment outcomes and the potential of combination regimens to effectively manage NM in breast cancer.

EXPERT OPINION

Challenges in treating NM include debates over clinical trial end points and the management of adverse effects. Drug resistance and low response rates are significant hurdles, particularly inHER2-negative breast cancer. The development of more precise and cost-effective medications with improved selectivity is crucial. Additionally, global efforts are needed for infrastructure development and cancer control considering the diverse nature of the disease.

Multivesicular liposome: A lipid-based drug delivery system for efficient drug delivery

The advancement of delivery tools for therapeutic agents has brought several novel formulations with increased drug loading, sustained release, targeted delivery, and prolonged efficacy. Amongst the several novel delivery approaches, multivesicular liposome has gained potential interest because this delivery system possesses the above advantages. In addition, this multivesicular liposomal delivery prevents degradation of the entrapped drug within the physiological environment while administered. The special structure of the vesicles allowed successful entrapment of hydrophobic and hydrophilic therapeutic agents, including proteins and peptides. Furthermore, this novel formulation could maintain the desired drug concentration in the plasma for a prolonged period, which helps to reduce the dosing frequencies, improve bioavailability, and safety. This tool could also provide stability of the formulation, and finally gaining patient compliance. Several multivesicular liposomes received approval for clinical research, while others are at different stages of laboratory research. In this review, we have focused on the preparation of multivesicular liposomes along with their application in different ailments for the improvement of the performance of the entrapped drug. Moreover, the challenges of delivering multivesicular vesicles have also been emphasized. Overall, it could be inferred that multivesicular liposomal delivery is a novel platform of advanced drug delivery with improved efficacy and safety.

What Went Wrong with Anticancer Nanomedicine Design and How to Make It Right

The three design criteria of anticancer nanomedicines to improve anticancer efficacy and to reduce toxicity have been debated for decades: (1) Nanomedicines increase drug accumulation through enhanced permeability and retention (EPR) in tumors to improve anticancer efficacy. (2) Long systemic circulation of nanomedicines with high plasma concentration reduces reticuloendothelial system (RES) clearance and decreases drug accumulation in the normal organs to reduce toxicity, and to enhance the EPR effect. (3) A universal nanodelivery platform based on EPR and long systemic circulation can be developed to deliver different anticancer drugs. Although these criteria have repeatedly been confirmed in preclinical xenograft cancers, the majority of anticancer nanomedicines have failed to improve clinical efficacy, while the clinical efficacies/safety of successful nanomedicines are inconsistent with these design criteria. First, the debate over tumor EPR may have mixed two different questions and missed more clinically relevant comparisons for nanomedicines versus free drugs. When tumors are compared with normal tissues, tumor EPR has been confirmed in both mouse xenograft tumors and human cancers. However, nanomedicines may not enhance drug accumulation in human tumors compared with free drugs, despite outstanding improvement in preclinical cancers. Heterogeneity of enhanced permeability and retention in human cancers occurs for small/large molecules and nanomedicines, which cannot fully explain the poor translation of nanomedicines' efficacy from preclinical cancer models to cancer patients. Second, long-circulation nanomedicine should not be used as a universal design criterion because it does not further improve tumor accumulation by tumor EPR in human patients nor universally reduce distribution in normal organs. In contrast, nanomedicines change the drug tissue distribution to alter anticancer efficacy/safety. Third, a universal nanodelivery platform that uses the same design criteria for different drugs is not feasible. Rather, drug-specific nanodelivery systems are required to overcome the intrinsic shortcomings of delivered drugs, which are determined by the physicochemical, pharmacokinetic, and pharmacodynamic properties of the delivered drugs and nanocarriers to improve their efficacy/safety.

Intrathecal drug delivery in the era of nanomedicine

Administration of substances directly into the cerebrospinal fluid (CSF) that surrounds the brain and spinal cord is one approach that can circumvent the blood-brain barrier to enable drug delivery to the central nervous system (CNS). However, molecules that have been administered by intrathecal injection, which includes intraventricular, intracisternal, or lumbar locations, encounter new barriers within the subarachnoid space. These barriers include relatively high rates of turnover as CSF clears and potentially inadequate delivery to tissue or cellular targets. Nanomedicine could offer a solution. In contrast to the fate of freely administered drugs, nanomedicine systems can navigate the subarachnoid space to sustain delivery of therapeutic molecules, genes, and imaging agents within the CNS. Some evidence suggests that certain nanomedicine agents can reach the parenchyma following intrathecal administration. Here, we will address the preclinical and clinical use of intrathecal nanomedicine, including nanoparticles, microparticles, dendrimers, micelles, liposomes, polyplexes, and other colloidalal materials that function to alter the distribution of molecules in tissue. Our review forms a foundational understanding of drug delivery to the CSF that can be built upon to better engineer nanomedicine for intrathecal treatment of disease.

Leptomeningeal metastasis

Leptomeningeal metastasis (LM) results from dissemination of cancer cells to both the leptomeninges (pia and arachnoid) and cerebrospinal fluid (CSF) compartment. Breast cancer, lung cancer, and melanoma are the most common solid tumors that cause LM. Recent approval of more active anticancer therapies has resulted in improvement in survival that is partly responsible for an increased incidence of LM. Neurologic deficits, once manifest, are mostly irreversible, and often have a significant impact on patient quality of life. LM-directed therapy is based on symptom palliation, circumscribed use of neurosurgery, limited field radiotherapy, intra-CSF and systemic therapies. Novel methods of detecting LM include detection of CSF circulating tumor cells and tumor cell-free DNA. A recent international guideline for a standardization of response assessment in LM may improve cross-trial comparisons as well as within-trial evaluation of treatment. An increasing number of retrospective studies suggest that molecular-targeted therapy, such as EGFR and ALK inhibitors in lung cancer, trastuzumab in HER2+ breast cancer, and BRAF inhibitors in melanoma, may be effective as part of the multidisciplinary management of LM. Prospective randomized trials with standardized response assessment are needed to further validate these preliminary findings.

An overview on the current status of cancer nanomedicines

PURPOSE

Cancer remains a significant cause of morbidity and mortality across the globe. A recent report suggests around 14.1 million new cases and 8.2 million cancer-related deaths, which are expected to reach 21.7 million and 13 million by 2030 worldwide, respectively.

MATERIALS AND METHODS

Because of highly complex mechanisms of cancer progression, it is important to explore and develop new innovative technologies which are more efficient compared with presently available treatment options.

RESULTS

Currently, chemotherapy, radiation and surgery are the most commonly used cancer treatment methods. In the last decade, nanomedicine emerged as an alternative treatment option that uses specific drug-delivery systems, improves efficacy of drugs and reduces detrimental side effects to normal tissues.

CONCLUSION

In this review, we have summarized cancer nanomedicines (active and passive drug delivery) available in the market. We have also discussed other nanomedicines that are at different stages of clinical trials.

Analysis of the role of intratecal liposomal cytarabine in the prophylaxis and treatment of central nervous system lymphomatosis: The Balearic Lymphoma Group experience

Central nervous system (CNS) lymphomatosis is a fatal complication of aggressive non-Hodgkin lymphoma (NHL). In lymphoblastic or Burkitt lymphoma, without specific CNS prophylaxis the risk of CNS relapse is 20–30%. DLBCL has a lower risk of relapse (around 5%) but several factors increase its incidence. There is no consensus or trials to conclude which is the best CNS prophylaxis. Best results seem to be associated with the use of intravenous (iv) high-dose methotrexate (HDMTX) but with a significant toxicity. Other options are the administration of intrathecal (IT) MTX, cytarabine or liposomal cytarabine (ITLC). Our aim is to analyze the experience of the centers of the Balearic Lymphoma Group (BLG) about the toxicity and efficacy of ITLC in the prophylaxis and therapy of CNS lymphomatosis. We retrospectively reviewed cases from 2005 to 2015 (n = 58) treated with ITLC. Our toxicity results were: 33% headache, 20% neurological deficits, 11% nausea, 9% dizziness, 4% vomiting, 4% fever, 2% transient blindness and 2% photophobia. In the prophylactic cohort (n = 26) with a median follow-up of 55 months (17–81) only 3 CNS relapses (11%) were observed (testicular DLBCL, Burkitt and plasmablastic lymphoma, with a cumulative incidence of 8%, 14% and 20% respectively). In the treatment cohort (n = 32), CSF complete clearance was obtained in 77% cases. Median OS was 6 months (0–16). Death causes were lymphoma progression (19 patients, 79%), treatment toxicity (2 patients) and non-related (3 patients, 12%). Toxicity profile was good especially when concomitant dexamethasone was administered. In the prophylactic cohort the incidence of CNS relapse in DLBCL group was similar to previously reported for HDMTX and much better than IT MTX. A high number of ITLC injections was associated with better rates of CSF clearance, clinical responses, PFS and lower relapses. Survival is still poor in CNS lymphomatosis and new therapeutic approaches are still needed.

Liposome technologies and drug delivery to the CNS

Brain and nervous system disorders represent a large unmet medical need. Central nervous system drug development is hampered by the restricted transport of drugs across the blood-brain barrier. Different strategies to deliver drugs to the brain have been developed. We discuss the current status of development of liposomal drug delivery to the brain. There is a growing interest in targeted delivery of liposomes to the brain and much progress has been made towards successful development of novel treatments for patients with devastating brain diseases.

Radionuclide imaging of liposomal drug delivery

INTRODUCTION

Ever since their discovery, liposomes have been radiolabeled to monitor their fate in vivo. Despite extensive preclinical studies, only a limited number of radiolabeled liposomal formulations have been examined in patients. Since they can play a crucial role in patient management, it is of importance to enable translation of radiolabeled liposomes into the clinic.

AREAS COVERED

Liposomes have demonstrated substantial advantages as drug delivery systems and can be efficiently radiolabeled. Potentially, radiolabeled drug-loaded liposomes form an elegant theranostic system, which can be tracked in vivo using single-photon emission computed tomography (SPECT) or positron emission tomography (PET) imaging. In this review, we discuss important aspects of liposomal research with a focus on the use of radiolabeled liposomes and their potential role in drug delivery and monitoring therapeutic effects.

EXPERT OPINION

Radiolabeled drug-loaded liposomes have been poorly investigated in patients and no radiolabeled liposomes have been approved for use in clinical practice. Evaluation of the risks, pharmacokinetics, pharmacodynamics and toxicity is necessary to meet pharmaceutical and commercial requirements. It remains to be demonstrated whether the results found in animal studies translate to humans before radiolabeled liposomes can be implemented into clinical practice.

[Relapse of acute promyelocytic leukemia in the central nervous system revealed by isolated dementia]

INTRODUCTION

Approximately 1.5% of dementia is due to curable aetiology. We report an isolated dementia syndrome due to a meningeal relapse of acute promyelocytic leukaemia with favourable outcome after appropriate treatment.

CASE REPORT

A 72-year-old woman, in remission of an acute promyelocytic leukaemia, presented a loss of autonomy for several months due to corticosubcortical dementia. Lumbar puncture showed blast cells indicating meningeal relapse of leukaemia. Intrathecal chemotherapy and arsenic trioxide obtained biological and molecular remission as well as restoration of normal cognitive functions.

CONCLUSION

In patients with hematologic past history such as acute promyelocytic leukaemia, an isolated cognitive impairment should alert physicians to search for an isolated neuromeningeal relapse.

Advances and Challenges of Liposome Assisted Drug Delivery

The application of liposomes to assist drug delivery has already had a major impact on many biomedical areas. They have been shown to be beneficial for stabilizing therapeutic compounds, overcoming obstacles to cellular and tissue uptake, and improving biodistribution of compounds to target sites in vivo. This enables effective delivery of encapsulated compounds to target sites while minimizing systemic toxicity. Liposomes present as an attractive delivery system due to their flexible physicochemical and biophysical properties, which allow easy manipulation to address different delivery considerations. Despite considerable research in the last 50 years and the plethora of positive results in preclinical studies, the clinical translation of liposome assisted drug delivery platforms has progressed incrementally. In this review, we will discuss the advances in liposome assisted drug delivery, biological challenges that still remain, and current clinical and experimental use of liposomes for biomedical applications. The translational obstacles of liposomal technology will also be presented.