Safety and toxicity of intrathecal liposomal cytarabine (Depocyte) in children and adolescents with recurrent or refractory brain tumors: a multi-institutional retrospective study. Anticancer Drugs. 2009;20:794-799. [PMID: 19617818 DOI: 10.1097/cad.0b013e32832f4abe]

The leptomeninges as a critical organ for normal CNS development and function: First patient and public involved systematic review of arachnoiditis (chronic meningitis)

BACKGROUND & IMPORTANCE

This patient and public-involved systematic review originally focused on arachnoiditis, a supposedly rare "iatrogenic chronic meningitis" causing permanent neurologic damage and intractable pain. We sought to prove disease existence, causation, symptoms, and inform future directions. After 63 terms for the same pathology were found, the study was renamed Diseases of the Leptomeninges (DLMs). We present results that nullify traditional clinical thinking about DLMs, answer study questions, and create a unified path forward.

METHODS

The prospective PRISMA protocol is published at Arcsology.org. We used four platforms, 10 sources, extraction software, and critical review with ≥2 researchers at each phase. All human sources to 12/6/2020 were eligible for qualitative synthesis utilizing R. Weekly updates since cutoff strengthen conclusions.

RESULTS

Included were 887/14286 sources containing 12721 DLMs patients. Pathology involves the subarachnoid space (SAS) and pia. DLMs occurred in all countries as a contributor to the top 10 causes of disability-adjusted life years lost, with communicable diseases (CDs) predominating. In the USA, the ratio of CDs to iatrogenic causes is 2.4:1, contradicting arachnoiditis literature. Spinal fusion surgery comprised 54.7% of the iatrogenic category, with rhBMP-2 resulting in 2.4x more DLMs than no use (p<0.0001). Spinal injections and neuraxial anesthesia procedures cause 1.1%, and 0.2% permanent DLMs, respectively. Syringomyelia, hydrocephalus, and arachnoid cysts are complications caused by blocked CSF flow. CNS neuron death occurs due to insufficient arterial supply from compromised vasculature and nerves traversing the SAS. Contrast MRI is currently the diagnostic test of choice. Lack of radiologist recognition is problematic.

DISCUSSION & CONCLUSION

DLMs are common. The LM clinically functions as an organ with critical CNS-sustaining roles involving the SAS-pia structure, enclosed cells, lymphatics, and biologic pathways. Cases involve all specialties. Causes are numerous, symptoms predictable, and outcomes dependent on time to treatment and extent of residual SAS damage. An international disease classification and possible treatment trials are proposed.

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.

Nanomedicines - Tiny particles and big challenges

After decades of research, nanotechnology has been used in a broad array of biomedical products including medical devices, drug products, drug substances, and pharmaceutical-grade excipients. But like many great achievements in science, there is a fine balance between the risks and opportunities of this new technology. Some materials and surface structures in the nanosize range can exert unexpected toxicities and merit a more detailed safety assessment. Regulatory agencies such as the United States Food and Drug Administration or the European Medicines Agency have started dealing with the potential risks posed by nanomaterials. Considering that a thorough characterization is one of the key aspects of controlling such risks this review presents the regulatory background of nanosafety assessment and provides some practical advice on how to characterize nanomaterials and drug formulations. Further, the challenges of how to maintain and monitor pharmaceutical quality through a highly complex production processes will be discussed.

Nanomedicines for Pediatric Cancers

Chemotherapy protocols for childhood cancers are still problematic due to the high toxicity associated with chemotherapeutic agents and incorrect dosing regimens extrapolated from adults. Nanotechnology has demonstrated significant ability to reduce toxicity of anticancer compounds. Improvement in the therapeutic index of cytostatic drugs makes this strategy an alternative to common chemotherapy in adults. However, the lack of nanomedicines specifically for pediatric cancer care raises a medical conundrum. This review highlights the current state and progress of nanomedicine in pediatric cancer and discusses the real clinical challenges and opportunities.

Antiglioma effects of cytarabine on leptomeningeal metastasis of high-grade glioma by targeting the PI3K/Akt/mTOR pathway

Leptomeningeal metastasis (LM) of high-grade glioma is a highly lethal disease requiring new effective therapeutic measures. For both de novo or relapsed glioma with LM, intrathecal cytarabine chemotherapy is not frequently used for first-line and relapse protocols. We encountered a clinical case demonstrating effective application of cytarabine in high-grade glioma with LM, prompting us to explore the effects of cytarabine on malignant glioma and molecular mechanisms of such effects through in vivo and in vitro experiments. The U87 cell line was selected to represent human glioma for studies. Cell viability was measured by MTT assay, plate colony formation assay, and trypan-blue dye exclusion test. Apoptosis was assessed by flow cytometry. Protein expression levels were detected by Western blot assay and immunohistochemistry. mRNA expression was examined by quantitative real-time reverse transcription polymerase chain reaction. Cytarabine inhibited tumor growth during the in vivo experiment. The present study confirmed that cytarabine inhibits proliferation and promotes apoptosis of U87 cells, and molecular analysis of this effect showed that cytarabine significantly reduces expression of phosphatidylinositol 3-kinase/serine/threonine kinase also known as the protein kinase B/mechanistic target of rapamycin (PI3K/Akt/mTOR) pathway, Ki-67, BCL2, and 4-1BB, and upregulates Bax and cleaved caspase-3. Our findings indicated that intrathecal administration of cytarabine manifests potential in prophylaxis and treatment of malignant glioma with LM. Effective medications for high-grade glioma with LM should contain cytarabine.

Central Nervous System Complications in Children Receiving Chemotherapy or Hematopoietic Stem Cell Transplantation

Therapy-related neurotoxicity greatly affects possibility of survival and quality of life of pediatric patients treated for cancer. Central nervous system (CNS) involvement is heterogeneous, varying from very mild and transient symptoms to extremely severe and debilitating, or even lethal syndromes. In this review, we will discuss the broad scenario of CNS complications and toxicities occurring during the treatment of pediatric patients receiving both chemotherapies and hematopoietic stem cell transplantation. Different types of complications are reviewed ranging from therapy related to cerebrovascular with a specific focus on neuroradiologic and clinical features.

Intraventricular etoposide safety and toxicity profile in children and young adults with refractory or recurrent malignant brain tumors

Systemic administration of etoposide is effective in treating metastatic, recurrent or refractory brain tumors, but penetration into the cerebrospinal fluid is extremely poor. This study was designed to determine the safety and toxicity profile of intraventricular etoposide administration and was affiliated with the prospective, multicenter, nonblinded, nonrandomized, multi-armed HIT-REZ-97 trial. The study enrolled 68 patients, aged 1.1-34.6 (median age 11 years). Adverse events that could possibly be related to intraventricular etoposide therapy were documented and analyzed. Intraventricular etoposide was simultaneously administered with either oral or intravenous chemotherapy in 426 courses according to three major schedules varying in dosing (0.25-1 mg), frequency of administration (bolus injection, every 12 or 24 h), course duration (5-10 days) and length of interval between courses (2-5 weeks). Potential treatment-related adverse effects included transient headache, seizures, infection of the reservoir, nausea and neuropsychological symptoms. Hematological side effects were not observed. One patient, with history of multiple prior therapies, who received long-term intraventricular and oral etoposide treatment developed acute myeloid leukemia as a secondary malignancy. Overall intraventricular etoposide is well tolerated. The results of this study have warranted a phase II trial to determine the effectiveness of this regimen in disease stages with very limited therapeutic options.

Implications of Intrathecal Chemotherapy for Anaesthesiologists: A Brief Review

Intrathecal chemotherapy is routinely prescribed in medical oncology practice, either for prophylaxis or for treatment of leptomeningeal disease due to a primary haematological disease or a metastatic disease due to any other malignancy. As these groups of patients are coagulopathic either because of the disease per se or due to systemic chemotherapy, lumbar puncture in them is considered challenging and is expected to be performed by an anaesthesiologist because of their expertise in this procedure. However, the challenge is not only in performing the lumbar puncture safely but also in dealing with other issues like explaining and handling complications that can happen either due to the drug injected intrathecally or due to a neurodeficit occurring either due to the underlying coagulopathy or due to the progression of leptomeningeal disease.

Lipoprotein based drug delivery: Potential for pediatric cancer applications

While survival rates for patients with childhood cancers have substantially improved, the quality of life of the survivors is often adversely impacted by the residual effects of chemo and radiation therapy. Because of the existing metabolic and physiological disparities between pediatric and adult patients, the treatment of pediatric cancer patients poses special challenges to oncologists. While numerous clinical trials being conducted, to improve treatment outcomes for pediatric cancer patients, new approaches are required to increase the efficacy and to minimize the drug related toxic side effects. Nanotechnology is a potentially effective tool to overcome barriers to effective cancer therapeutics including poor bioavailability and non-specific targeting. Among the nano-delivery approaches, lipoprotein based formulations have shown particularly strong promise to improve cancer therapeutics. The present article describes the challenges faced in the treatment of pediatric cancers and reviews the potential of lipoprotein-based therapeutics for these malignancies.

Pharmacokinetics and toxicity of intrathecal liposomal cytarabine in children and adolescents following age-adapted dosing

BACKGROUND AND OBJECTIVE

Assessment of the optimal drug dose for intrathecal therapy in children is challenging because of the non-linear increase in cerebrospinal fluid (CSF) volume throughout childhood and potential differences in the elimination rate in children versus adults. The present study was designed to prospectively collect pharmacokinetic and safety data on age-adapted intrathecal liposomal cytarabine in children aged >3 years.

PATIENTS AND METHODS

Sixteen patients with malignant brain tumours were included in the study. Children aged 3-10 years received liposomal cytarabine 35 mg with concomitant dexamethasone, and those aged >10 years received 50 mg. Serial CSF and plasma samples were collected before administration and 1 h, 12 h, 24 h, 1 week and 2 weeks post-dosing. CSF was analysed for free and encapsulated cytarabine, and plasma was analysed for free cytarabine.

RESULTS

The average elimination half-life values in children aged 3-10 years and in those aged >10 years, treated with liposomal cytarabine 35 mg and 50 mg, respectively, were 40.9 and 43.7 h for free cytarabine and 31.5 and 36.4 h for encapsulated cytarabine in CSF. Although these values were lower than those previously reported, cytarabine concentrations exceeded the cytotoxic threshold of 0.1 mg/L in all patients until 1 week post-intraventricular administration. Cytarabine concentrations in plasma were negligible. In general, liposomal cytarabine was well tolerated, with relevant but manageable toxicities.

CONCLUSION

Liposomal cytarabine in doses of 35 mg for children aged 3-10 years and 50 mg for older patients shows sufficient drug exposure for at least 1 week and appears to be well tolerated.

Nanomedicine in cerebral palsy

Cerebral palsy is a chronic childhood disorder that can have diverse etiologies. Injury to the developing brain that occurs either in utero or soon after birth can result in the motor, sensory, and cognitive deficits seen in cerebral palsy. Although the etiologies for cerebral palsy are variable, neuroinflammation plays a key role in the pathophysiology of the brain injury irrespective of the etiology. Currently, there is no effective cure for cerebral palsy. Nanomedicine offers a new frontier in the development of therapies for prevention and treatment of brain injury resulting in cerebral palsy. Nanomaterials such as dendrimers provide opportunities for the targeted delivery of multiple drugs that can mitigate several pathways involved in injury and can be delivered specifically to the cells that are responsible for neuroinflammation and injury. These materials also offer the opportunity to deliver agents that would promote repair and regeneration in the brain, resulting not only in attenuation of injury, but also enabling normal growth. In this review, the current advances in nanotechnology for treatment of brain injury are discussed with specific relevance to cerebral palsy. Future directions that would facilitate clinical translation in neonates and children are also addressed.

Treatment for recurrent medulloblastoma with intrathecal liposomal cytarabine and systemic metronomic combination therapy

The prognosis of recurrent medulloblastoma is dismal, with a median survival of less than 1 year. Our patient was initially diagnosed with high-risk medulloblastoma when he was 14 years old. He had a recurrence 18 months after the end of therapy. Recurrence treatment consisted of 13 intrathecal applications of liposomal cytarabine over an 18-month period, and oral metronomic antiangiogenic therapy with thalidomide, celecoxib, and etoposide. Side effects from the intrathecal treatment were most likely related to arachnoiditis despite prolonged prophylaxis with steroids. He also developed partial hearing loss. Neutropenia was the main side effect of the metronomic therapy. He remains alive, with a good quality of life and without evidence of disease 34 months from the start of recurrence therapy. This combination of local antineoplastic and systemic antiangiogenic therapy seems to be promising for recurrent medulloblastoma. However, more patients and standardized protocols are needed to verify the benefit of this combination therapy and to define the correct duration of treatment.

Self-assembled squalenoyl-cytarabine nanostructures as a potent nanomedicine for treatment of leukemic diseases

Background

In this investigation, the antileukemic activity of a new nanomedicine based on the conjugation of 1,1′,2-tris-nor-squalenic acid with cytarabine (Ara-C) was evaluated.

Methods

Squalenoyl-Ara-C conjugate (Sq-Ara-C) self-assembled nanosystems were obtained by the nanoprecipitation method and characterized in vitro and in vivo.

Results

This new nanomedicine, which had a mean diameter of approximately 150 nm, improved the in vitro antitumoral activity of Ara-C in different cancer cell lines (L1210, K562, and MCF-7). Sq-Ara-C nanomedicine allowed reduction of the IC₅₀ value with respect to the free drug and was also active against drug-resistant leukemic cells (L1210R). A noticeable increase in the survival rate of mice with aggressive metastatic L1210R leukemia was observed after treatment with Sq-Ara-C (50 mg/kg) as compared with the free active compound (100 mg/kg). Finally, evaluation of the biodistribution and pharmacokinetic profiles of the drug demonstrated that these nanoaggregates preferentially localized to the liver and spleen, and protected the drug from physiological metabolism.

Conclusion

Squalenoylation of cytarabine offers several pharmacological benefits both in vitro and in vivo.

Targeting the neurovascular unit for treatment of neurological disorders

Drug discovery for CNS disorders has been restricted by the inability for therapeutic agents to cross the blood-brain barrier (BBB). Moreover, current drugs aim to correct neuron cell signaling, thereby neglecting pathophysiological changes affecting other cell types of the neurovascular unit (NVU). Components of the NVU (pericytes, microglia, astrocytes, and neurons, and basal lamina) act as an intricate network to maintain the neuronal homeostatic microenvironment. Consequently, disruptions to this intricate cell network lead to neuron malfunction and symptoms characteristic of CNS diseases. A lack of understanding in NVU signaling cascades may explain why current treatments for CNS diseases are not curative. Current therapies treat symptoms by maintaining neuron function. Refocusing drug discovery to sustain NVU function may provide a better method of treatment by promoting neuron survival. In this review, we will examine current therapeutics for common CNS diseases, describe the importance of the NVU in cerebral homeostasis and discuss new possible drug targets and technologies that aim to improve treatment and drug delivery to the diseased brain.

Translocator protein (TSPO) ligand-Ara-C (cytarabine) conjugates as a strategy to deliver antineoplastic drugs and to enhance drug clinical potential

The aim of this work was to evaluate TSPO ligand-Ara-C conjugation as an approach for the selective delivery of the antineoplastic agent to brain tumors as well as for overcome P-gp resistance induction observed for the majority of cytotoxic agents, enhancing the drug clinical potential. To this end, the novel N-imidazopyridinacetyl-Ara-C conjugates 3a-c, 10 and 15 have been prepared and evaluated for their cytotoxicity against glioma cell lines. In contrast to that observed for 3a-c and 10, the conjugate 15 resulted stable in both phosphate buffer and physiological medium. In all cases, the release of free Ara-C from hydrolyzed conjugates was checked by HPLC and ESI-MS analysis. Conjugates 10 and 15 displayed very high in vitro TSPO affinity and selectivity, and, hence, they may possess potential for targeted brain delivery. Due to the favorable features displayed by the conjugate 15, it was further evaluated on glioma cell lines, expressing high levels of TSPO, in the presence and in the absence of specific nucleoside transport (NT) inhibitors. In contrast to that observed for the free Ara-C, the presence of NT inhibitors did not reduce the cytotoxic activity of 15. Moreover, conjugate 15, as N(4)-acyl derivative of Ara-C, should be resistant to inactivation by cytidine deaminase, and it may possess enhanced propensity to target brain tumor cells characterized by a reduced expression of NTs. In addition, this conjugate behaves as a clear P-gp modulator and thereby may be useful to reverse MDR. Transport studies across the MDCKII-MDR1 monolayer indicated that conjugate 15 should overcome the BBB by transcellular pathway. All these features may be useful for enhancing the clinical potential of the nucleoside drug Ara-C.

Intrathecal liposomal cytarabine in relapsed or refractory infant and pediatric leukemias: the Children's Hospital of Philadelphia experience and review of the literature

Intrathecal chemotherapy is integral to curing childhood leukemia; however, bioavailability is limited by the blood-brain barrier. Recently FDA-approved, intrathecal liposomal cytarabine (ITlipAC) increases drug concentration over time with fewer invasive procedures. We present a series of 4 children, including 2 infants, with relapsed central nervous system leukemia who went into remission using ITlipAC, with a review of the literature reporting ITlipAC use in children with relapsed leukemia. Drug-attributable side effects were observed more frequently in children with preexisting neurologic conditions and with adult dosing. Combined with other pediatric reports, our experience supports the efficacy of ITlipAC in pediatric and infant leukemic meningitis.

Neurologic complications after intrathecal liposomal cytarabine in combination with systemic polychemotherapy in primary CNS lymphoma

Intrathecal application of liposomal cytarabine (Ara-C) (DepoCyte(®)) has been associated with neurotoxicity when applied as part of a polychemotherapy regimen. Patients with primary central nervous system lymphoma treated with high-dose systemic methotrexate (MTX)- and Ara-C-based polychemotherapy including six cycles of liposomal Ara-C (50 mg intrathecally every 3 weeks) were prospectively monitored for neurotoxic side-effects. Between November 2005 and February 2009, 149 intrathecal applications of liposomal cytarabine (DepoCyte(®)) were carried out in 33 patients, 7 (21%) of whom developed an incomplete conus medullaris/cauda equina syndrome with incontinence for bladder (6) and bowel function (3) or lumbosacral polyradicular paresis (1), resolving only incompletely over a follow-up period of 9-30 months. In six of these seven patients, lumbosacral magnetic resonance imaging (MRI) was negative for leptomeningeal infiltration or arachnoiditis. Cerebrospinal fluid (CSF) analysis performed in six of these seven patients showed normal cell count in all and increased total protein in four of them. One patient among these seven suffered a seizure without other identifiable causes. Conus/cauda syndrome has to be considered as a serious potential neurotoxic side-effect in patients receiving liposomal Ara-C as part of a multimodal regimen including high-dose systemic MTX and Ara-C.

Liposomal cytarabine for central nervous system embryonal tumors in children and young adults

To assess the tolerability and efficacy of liposomal cytarabine (LC), an encapsulated, sustained-release, intrathecal (IT) formulation of cytosine arabinoside, in de novo and relapsed central nervous system (CNS) embryonal tumors in children and young adults. We studied retrospectively all patients less than age 30 at our institution treated consecutively with LC for medulloblastoma (MB), primitive neuroectodermal tumor (PNET), and atypical teratoid rhabdoid tumor (ATRT). Seventeen patients received LC (2 mg/kg up to 50 mg, every 2 weeks to monthly) at diagnosis of high-risk CNS embryonal tumor (2 PNET, 3 ATRT) or relapse of MB (12 MB; 9 had leptomeningeal metastases). Sixteen patients received concurrent systemic chemotherapy. A total of 108 doses were administered (IT 82, intraventricular 26) with a mean of six (range 1-16) treatments per patient. Only three administrations were associated with adverse effects of arachnoiditis or headache. None developed malignant cerebrospinal fluid (CSF) cytology while receiving LC. All the six evaluable patients with malignant CSF cytology and treated with at least two doses cleared their CSF (mean 3 doses, range 1-5). Median overall survival in relapse patients was 9.1 months. Five patients (4 de novo and 1 relapsed) remain alive in complete remission for a median 26.8 months from first LC. Liposomal cytarabine is an easily administered, well-tolerated, and active drug in patients with high-risk embryonal neoplasms. One-third of our cohort remains in remission from otherwise fatal diagnoses. Our findings warrant a phase II trial of LC in newly diagnosed or recurrent CNS embryonal tumors.