Phase I trial of lenalidomide in pediatric patients with recurrent, refractory, or progressive primary CNS tumors: Pediatric Brain Tumor Consortium study PBTC-018

Immunotherapy for pediatric low-grade gliomas

Pediatric low-grade gliomas (pLGGs) are the most common brain tumor types affecting children. Although gross-total resection remains the treatment of choice, many tumors are not amenable to complete removal, because they either involve midline structures, such as the optic chiasm or hypothalamus, and are not conducive to aggressive resection, or have diffuse biological features and blend with the surrounding brain. Historically, radiation therapy was used as the second-line option for disease control, but with the recognition that this often led to adverse long-term sequelae, particularly in young children, conventional chemotherapy assumed a greater role in initial therapy for unresectable tumors. A variety of agents demonstrated activity, but long-term disease control was suboptimal, with more than 50% of tumors exhibiting disease progression within 5 years. More recently, it has been recognized that a high percentage of these tumors in children exhibit constitutive activation of the mitogen-activated protein kinase (MAPK) pathway because of BRAF translocations or mutations, NFI mutations, or a host of other anomalies that converged on MAPK. This led to phase 1, 2, and 3 trials that explored the activity of blocking this signaling pathway, and the efficacy of this approach compared to conventional chemotherapy. Despite initial promise of these strategies, not all children tolerate this therapy, and many tumors resume growth once MAPK inhibition is stopped, raising concern that long-term and potentially life-long treatment will be required to maintain tumor control, even among responders. This observation has led to interest in other treatments, such as immunotherapy, that may delay or avoid the need for additional treatments. This chapter will summarize the place of immunotherapy in the current armamentarium for these tumors and discuss prior results and future options to improve disease control, with a focus on our prior efforts and experience in this field.

An Overview of Optic Pathway Glioma With Neurofibromatosis Type 1: Pathogenesis, Risk Factors, and Therapeutic Strategies

Optic pathway gliomas (OPGs) are most predominant pilocytic astrocytomas, which are typically diagnosed within the first decade of life. The majority of affected children with OPGs also present with neurofibromatosis type 1 (NF1), the most common tumor predisposition syndrome. OPGs in individuals with NF1 primarily affect the optic pathway and lead to visual disturbance. However, it is challenging to assess risk in asymptomatic patients without valid biomarkers. On the other hand, for symptomatic patients, there is still no effective treatment to prevent or recover vision loss. Therefore, this review summarizes current knowledge regarding the pathogenesis of NF1-associated OPGs (NF1-OPGs) from preclinical studies to seek potential prognostic markers and therapeutic targets. First, the loss of the NF1 gene activates 3 distinct Ras effector pathways, including the PI3K/AKT/mTOR pathway, the MEK/ERK pathway, and the cAMP pathway, which mediate glioma tumorigenesis. Meanwhile, non-neoplastic cells from the tumor microenvironment (microglia, T cells, neurons, etc.) also contribute to gliomagenesis via various soluble factors. Subsequently, we investigated potential genetic risk factors, molecularly targeted therapies, and neuroprotective strategies for tumor prevention and vision recovery. Last, potential directions and promising preclinical models of NF1-OPGs are presented for further research. On the whole, NF1-OPGs develop as a result of the interaction between glioma cells and the tumor microenvironment. Developing effective treatments require a better understanding of tumor molecular characteristics, as well as multistage interventions targeting both neoplastic cells and non-neoplastic cells.

Immunomodulatory drugs: a promising clinical ally for cancer immunotherapy

While immunomodulatory imide drugs (IMiDs) have been authorised for treatment of haematological cancers for over two decades, the appreciation of their ability to stimulate antitumour T cell and natural killer (NK) cell responses is relatively recent. Clinical trial data increasingly show that targeted immunotherapies, such as antibodies, T cells, and vaccines, improve outcomes when delivered in combination with the IMiD derivatives lenalidomide or pomalidomide. Here, we review these clinical data to highlight the relevance of IMiDs in combinatorial immunotherapy for both haematological and solid tumours. Further research into the molecular mechanisms of IMiDs and an increased understanding of their immunomodulatory effects may refine the specific applications of IMiDs and improve the design of future clinical trials, moving IMiDs to the forefront of combinatorial cancer immunotherapy.

Posterior fossa tumors in children: current insights

While in adults most intracranial tumors develop around the cerebral hemispheres, 45 to 60% of pediatric lesions are found in the posterior fossa, although this anatomical region represents only 10% of the intracranial volume. The latest edition of the WHO classification for CNS tumors presented some fundamental paradigm shifts that particularly affected the classification of pediatric tumors, also influencing those that affect posterior fossa. Molecular biomarkers play an important role in the diagnosis, prognosis, and treatment of childhood posterior fossa tumors and can be used to predict patient outcomes and response to treatment and monitor its effectiveness. Although genetic studies have identified several posterior fossa tumor types, differing in terms of their location, cell of origin, genetic mechanisms, and clinical behavior, recent management strategies still depend on uniform approaches, mainly based on the extent of resection. However, significant progress has been made in guiding therapy decisions with biological or molecular stratification criteria and utilizing molecularly targeted treatments that address specific tumor biological characteristics. The primary focus of this review is on the latest advances in the diagnosis and treatment of common subtypes of posterior fossa tumors in children, as well as potential therapeutic approaches in the future.   Conclusion: Molecular biomarkers play a central role, not only in the diagnosis and prognosis of posterior fossa tumors in children but also in customizing treatment plans. They anticipate patient outcomes, measure treatment responses, and assess therapeutic effectiveness. Advances in neuroimaging and treatment have significantly enhanced outcomes for children with these tumors. What is Known: • Central nervous system tumors are the most common solid neoplasms in children and adolescents, with approximately 45 to 60% of them located in the posterior fossa. • Multimodal approaches that include neurosurgery, radiation therapy, and chemotherapy are typically used to manage childhood posterior fossa tumors What is New: • Notable progress has been achieved in the diagnosis, categorization and management of posterior fossa tumors in children, leading to improvement in survival and quality of life.

Phase II Randomized Trial of Lenalidomide in Children With Pilocytic Astrocytomas and Optic Pathway Gliomas: A Report From the Children's Oncology Group

PURPOSE

Children with low-grade glioma often require long-term therapy and suffer from treatment morbidity. Although targeted agents are promising, tumor targets often encompass normal developmental pathways and long-term effects of inhibition are unknown. Lenalidomide is an immunomodulatory agent with wide-ranging properties. Phase I studies indicated greater tolerability of lenalidomide in children compared with adults and a potential dose-response effect.

PATIENTS AND METHODS

We performed a phase II trial of lenalidomide in children with pilocytic astrocytomas and optic pathway gliomas who failed initial therapy. Primary objectives included determination of objective response rate of children randomly assigned to regimen A, low-dose (20 mg/m2/dose), or regimen B, high-dose (115 mg/m2/dose) lenalidomide, and assessment for early progression. Secondary objectives included estimation of event-free survival, overall survival, incidence of toxic events, and assessment of plasma lenalidomide concentrations. Lenalidomide was administered once daily × 21 days of each 28-day cycle for each regimen.

RESULTS

Seventy-four eligible patients were enrolled (n = 37, each arm). The predefined activity level of interest was achieved for both arms. Four objective responses were observed in each arm, and the number of early progressors was low. Eighteen patients completed 26 cycles of therapy (regimen A, n = 12; regimen B, n = 6). The median number of cycles was 14 (range, 2-26) for regimen A and 11 for regimen B (range, 1-26). Of 74 eligible patients who received study drug, 30 required dose reduction for toxicity (regimen A, n = 6; regimen B, n = 24) and 16 discontinued because of toxicity (regimen A, n = 2; regimen B, n = 14).

CONCLUSION

Lenalidomide demonstrates a sufficient level of activity in children with low-grade glioma to warrant further exploration. Low-dose (20 mg/m2/dose administered once daily × 21 days of each 28-day cycle) lenalidomide appears to have better tolerability with comparable activity.

Thromboembolic toxicity observed with concurrent trametinib and lenalidomide therapy

The event-free survival of pediatric low-grade gliomas is poor, and patients often require multiple treatment strategies. While MEK and RAF inhibitors are efficacious in early-phase trials, not all patients respond, and many experience progression following completion of therapy. Evaluating combination therapies that may enhance efficacy or prolong disease stabilization is warranted. We report our institutional experience using concurrent trametinib and lenalidomide in the treatment of primary pediatric central and peripheral nervous system tumors. Two of four patients using this combination therapy experienced severe thromboembolic events, necessitating discontinuation of therapy. This combination requires further investigation, and we urge caution if used.

Species Specificity and Selection of Models for Drug Oxidations Mediated by Polymorphic Human Enzymes

Many drug oxygenations are mainly mediated by polymorphic cytochromes P450 (P450s) and also by flavin-containing monooxygenases (FMOs). More than 50 years of research on P450/FMO-mediated drug oxygenations have clarified their catalytic roles. The natural product coumarin causes hepatotoxicity in rats via the reactive coumarin 3,4-epoxide, a reaction catalyzed by P450 1A2; however, coumarin undergoes rapid 7-hydroxylation by polymorphic P450 2A6 in humans. The primary oxidation product of the teratogen thalidomide in rats is deactivated 5'-hydroxythalidomide plus sulfate and glucuronide conjugates; however, similar 5'-hydroxythalidomide and 5-hydroxythalidomide are formed in rabbits in vivo. Thalidomide causes human P450 3A enzyme induction in liver (and placenta) and is also activated in vitro and in vivo by P450 3A through the primary human metabolite 5-hydroxythalidomide (leading to conjugation with glutathione/nonspecific proteins). Species differences exist in terms of drug metabolism in rodents and humans, and such differences can be very important when determining the contributions of individual enzymes. The approaches used for investigating the roles of human P450 and FMO enzymes in understanding drug oxidations and clinical therapy have not yet reached maturity and still require further development. SIGNIFICANCE STATEMENT: Drug oxidations in animals and humans mediated by P450s and FMOs are important for understanding the pharmacological properties of drugs, such as the species-dependent teratogenicity of the reactive metabolites of thalidomide and the metabolism of food-derived odorous trimethylamine to non-odorous (but proatherogenic) trimethylamine N-oxide. Recognized differences exist in terms of drug metabolism between rodents, non-human primates, and humans, and such differences are important when determining individual liver enzyme contributions with substrates in in vitro and in vivo systems.

Italian Precision Medicine in Pediatric Oncology: Moving beyond Actionable Alterations

Neuroblastoma (NB) is the most common extracranial solid tumor encountered in childhood. Although there has been significant improvement in the outcomes of patients with high-risk disease, the prognosis for patients with metastatic relapse or refractory disease is poor. Hence, the clinical integration of genome sequencing into standard clinical practice is necessary in order to develop personalized therapy for children with relapsed or refractory disease. The PeRsonalizEdMEdicine (PREME) project focuses on the design of innovative therapeutic strategies for patients suffering from relapsed NB. We performed whole exome sequencing (WES) of patient-matched tumor-normal samples to identify genetic variants amenable to precision medicine. Specifically, two patients were studied (First case: a three-year-old male with early relapsed NB; Second case: a 20-year-old male who relapsed 10 years after the first diagnosis of NB). Results were reviewed by a multi-disciplinary molecular tumor board (MTB) and clinical reports were issued to the ordering physician. WES revealed the mutation c.G320C in the CUL4A gene in case 1 and the mutation c.A484G in the PSMC2 gene in case 2. Both patients were treated according to these actionable alterations, with promising results. The effective treatment of NB is one of the main challenges in pediatric oncology. In the era of precision medicine, the need to design new therapeutic strategies for NB is fundamental. Our results demonstrate the feasibility of incorporating clinical WES into pediatric oncology practice.

Outcome of Lenalidomide Treatment for Cognitive Impairment Caused by Immune Reconstitution Inflammatory Syndrome in Patients with HIV-Related Cryptococcal Meningitis

Purpose

Cognitive impairment associated with human immunodeficiency virus (HIV)-related cryptococcal meningitis (HCM) in the context of immune reconstitution inflammatory syndrome is difficult to address. This study was a follow-up of lenalidomide treatment outcomes in patients with HCM and cognitive impairment after complete cryptococcal clearance.

Patients and Methods

Seven HCM patients with neuroinflammation and cognitive impairment after complete cryptococcal clearance were enrolled in this prospective study. Neurocognitive assessment, clinical examination and cerebrospinal fluid (CSF) assays were performed before and after lenalidomide treatment.

Results

After lenalidomide treatment, the Montreal Cognitive Assessment [week (W) 0 (median [interquartile range]: 23.0 (13.0–24.0) vs W24: 26.0 (24.0–28.00), P=0.018] and International HIV Dementia Scale scores [W0: 9.0 (2.5–10.5) vs W24: 11.0 (10.00–12.0), P=0.028] improved significantly, mainly in the domain of memory function. There was no significant difference in the Center for Epidemiological Research Depression scores for anxiety and depression before and after treatment. Further stratified analyses revealed that the patients with cognitive improvement group had higher levels of CSF white blood cells [94.0 (44.0–180.0) vs 0 (0–1.5), P=0.032], CSF protein [4.9 (3.0–6.6) vs 0.6 (0.5–0.7), P=0.034], CSF albumin [318.5 (190.9–346.5) vs 33.5 (30.4–46.2), P=0.034], and CSF IgG [160.5 (73.8–256. 0) vs 4.7 (4.3–7.4), P=0.034] but a lower CSF glucose level [2.4 (2.0–2.7) vs 2.8 (2.8–3.9), P=0.032] than the patients with cognitive non-improvement group before treatment. CSF inflammatory cytokines of the growth-related oncogene, interleukin [IL]-10, granulocyte-colony stimulating factor, IL-6, IL-8, complement factor H, tumor necrosis factor-α, and α-2 macroglobulin were obviously decreased in patients with cognitive improvement group after lenalidomide treatment.

Conclusion

Lenalidomide potentially reduces cognitive impairment caused by immune reconstitution inflammatory syndrome in patients with HCM after cryptococcal clearance by inhibiting intracranial inflammation.

Low cerebrospinal fluid-to-plasma ratios of orally administered lenalidomide mediated by its low cell membrane permeability in patients with hematologic malignancies

Lenalidomide is a synthetic analog of thalidomide formed by the removal of one keto group (plus the addition of an amino group); it has anti-tumor activities beneficial for the treatment of hematologic malignancies. However, lenalidomide distribution to brain in animal models is reportedly low compared with that of thalidomide. The aim of this study was to evaluate plasma and cerebrospinal fluid concentrations of lenalidomide in three patients with malignant hematologic malignancies. Lenalidomide was detected in plasma from the three Japanese patients 1.5 h following oral administration of 20 mg lenalidomide using liquid chromatography/mass spectrometry, despite the in vitro gastrointestinal permeability of lenalidomide being low. Clinically observed cerebrospinal fluid-to-plasma ratios of lenalidomide were low (1.3-2.4%). Observed influx permeability values for lenalidomide in monkey blood-brain barrier model and human placental cell systems were one order of magnitude lower than those of thalidomide and another second-generation drug, pomalidomide along with a positive permeability control, caffeine. Because of the low cell-barrier permeability of lenalidomide demonstrated in in vitro assays, clinically relevant pharmacokinetic profiles of lenalidomide resulted in low penetrability from plasma into cerebrospinal fluid in patients with hematologic malignancies. Lenalidomide is conclusively suggested to expert its favorable immunomodulatory effects via systemic exposures in the patients.

Lenalidomide bypasses CD28 co-stimulation to reinstate PD-1 immunotherapy by activating Notch signaling

Programmed cell death protein 1 (PD-1) checkpoint blockade therapy requires the CD28 co-stimulatory receptor for CD8⁺ T cell expansion and cytotoxicity. However, CD28 expression is frequently lost in exhausted T cells and during immune senescence, limiting the clinical benefits of PD-1 immunotherapy in individuals with cancer. Here, using a cereblon knockin mouse model that regains in vivo T cell response to lenalidomide, an immunomodulatory imide drug, we show that lenalidomide reinstates the anti-tumor activity of CD28-deficient CD8⁺ T cells after PD-1 blockade. Lenalidomide redirects the CRL4^Crbn ubiquitin ligase to degrade Ikzf1 and Ikzf3 in T cells and unleashes paracrine interleukin-2 (IL-2) and intracellular Notch signaling, which collectively bypass the CD28 requirement for activation of intratumoral CD8⁺ T cells and inhibition of tumor growth by PD-1 blockade. Our results suggest that PD-1 immunotherapy can benefit from a lenalidomide combination when treating solid tumors infiltrated with abundant CD28^- T cells.

Recent Update in Pharmacological Agents for Optic Pathway Glioma

Optic pathway gliomas (OPGs) are insidious, debilitating low-grade tumors. They can affect the optic nerve, optic chiasm, and optic tracts and can be sporadic or associated with neurofibromatosis type 1 (NF1). The location of OPGs within the optic pathway typically precludes complete resection or optimal radiation dose. Treatment is unnecessary for sporadic and NF1-related OPGs that do not cause visual impairments. Chemotherapy is the mainstay of treatment for patients with progressive disease. However, outcomes following standard treatments have been mixed, and standardized outcome measurements are lacking. In recent years, newer molecularly targeted therapies such as anti-vascular endothelial growth factor (VEGF) monoclonal antibody, mitogen-activated protein kinase (MAPK) inhibitor, and mammalian target of rapamycin (mTOR) inhibitor, represent a promising treatment modality.

A Holistic Review on the Current and Future Status of Biology-Driven and Broad-Spectrum Therapeutic Options for Medulloblastoma

With a thorough investigation of the etiology of medulloblastomas, a comprehensive review was done to categorize available clinical trials in order to discuss the future potential of breakthroughs in treatment options. The pertinent issues of medulloblastoma therapy with radiation being inapplicable to children under the age of 3, and therapies causing toxicity are detailed and discussed in the context of understanding how the current therapies may address these suboptimal treatment modalities. This study aggregated published studies from the US government clinical trials website and filtered them based on their direct treatment towards medulloblastomas. Thirty-two clinical trials were applicable to be analyzed and the treatment mechanisms were discussed along with the efficacy; molecular groupings of medulloblastomas were also investigated. The investigated therapies tend to target sonic hedgehog (SHH)-subtype medulloblastomas, but there is a necessity for group 3 subtype and group 4 subtype to be targeted as well. Due to the heterogeneous nature of tumor relapse in groups 3 and 4, there are less specified trials towards those molecular groupings, and radiation seems to be the main scope of treatment. Medulloblastomas being primarily a pediatric tumor require treatment options that minimize radiation to increase the quality of living in children and to prevent long-term symptoms of over radiation. Exploring symptomatic treatment with donepezil in children with combination therapies may be a potential route for future trials; immunotherapies seem to hold potential in treating patients reacting adversely to radiation therapy.

Recurrent or progressive pediatric brain tumors: population pharmacokinetics and exposure-response analysis of pomalidomide

BACKGROUND

Pomalidomide, an immunomodulatory drug, was investigated for pediatric brain tumors. The objectives of this analysis were to characterize the PK of pomalidomide and to examine exposure-response relationship in pediatric patients with recurrent or progressive primary brain tumors.

METHODS

Nonlinear mixed effects modeling was employed in developing a population PK model of pomalidomide using a total of 343 concentrations from 70 patients. Logistic regression models were used for exposure-response analyses.

RESULTS

The PK of pomalidomide was adequately described with a one compartment model with first-order absorption and elimination. Body surface area (BSA) was identified as a statistically significant covariate of apparent clearance and volume of distribution; however, the impact of BSA on exposure parameters was not deemed clinically relevant. Pomalidomide exposure was not associated with higher probabilities of treatment-emergent adverse events or pomalidomide dose interruptions during Cycle 1. Covariates such as BSA, weight, sex, age, and race had no significant effect on safety endpoints. The PK of pomalidomide in pediatric patients with brain tumors was generally consistent with that in adult patients with multiple myeloma after adjustment for BSA.

CONCLUSIONS

This is the first study to characterize PK of pomalidomide in pediatric patients, which supports BSA-based dosing for pediatric patients.

IMPACT

This is the first study to characterize PK of pomalidomide in pediatric patients, which supports BSA-based dosing for pediatric patients. There is no significant pomalidomide PK difference between adults and pediatrics. Pomalidomide exposure was not associated with higher probabilities of treatment-emergent adverse event or pomalidomide dose interruptions during Cycle 1.

Is more better? An analysis of toxicity and response outcomes from dose-finding clinical trials in cancer

BACKGROUND

The overwhelming majority of dose-escalation clinical trials use methods that seek a maximum tolerable dose, including rule-based methods like the 3+3, and model-based methods like CRM and EWOC. These methods assume that the incidences of efficacy and toxicity always increase as dose is increased. This assumption is widely accepted with cytotoxic therapies. In recent decades, however, the search for novel cancer treatments has broadened, increasingly focusing on inhibitors and antibodies. The rationale that higher doses are always associated with superior efficacy is less clear for these types of therapies.

METHODS

We extracted dose-level efficacy and toxicity outcomes from 115 manuscripts reporting dose-finding clinical trials in cancer between 2008 and 2014. We analysed the outcomes from each manuscript using flexible non-linear regression models to investigate the evidence supporting the monotonic efficacy and toxicity assumptions.

RESULTS

We found that the monotonic toxicity assumption was well-supported across most treatment classes and disease areas. In contrast, we found very little evidence supporting the monotonic efficacy assumption.

CONCLUSIONS

Our conclusion is that dose-escalation trials routinely use methods whose assumptions are violated by the outcomes observed. As a consequence, dose-finding trials risk recommending unjustifiably high doses that may be harmful to patients. We recommend that trialists consider experimental designs that allow toxicity and efficacy outcomes to jointly determine the doses given to patients and recommended for further study.

Effect of Lenalidomide on Pentylenetetrazole-Induced Clonic Seizure Threshold in Mice: A Role for N-Methyl-D-Aspartic Acid Receptor/Nitric Oxide Pathway

Background and Purpose

Accumulating evidence suggest that lenalidomide, a structural analog of thalidomide, has neuro-modulatory and neuroprotective properties. In the present study, we investigated effects of acute administration of lenalidomide on clonic seizure threshold in mice induced by pentylenetetrazole (PTZ) and possible role of N-methyl-D-aspartic acid receptor (NMDAR) and nitric oxide (NO) pathway.

Methods

We have utilized a clonic model of seizure in NMRI mice induced by PTZ to evaluate the potential effect of lenalidomide on seizure threshold. Different doses of lenalidomide (5, 10, 20, and 50 mg/kg, intraperitoneal [i.p.]) were administered 1 hour before PTZ. To evaluate probable role of NMDAR/NO signaling, the non-selective NO synthase inhibitor L-N^G-nitroarginine methyl ester (L-NAME; 10 mg/kg, i.p.), neuronal NOS (nNOS) inhibitor 7-nitroindazole (7-NI; 30 mg/kg, i.p.), selective inducible NOS inhibitor aminoguanidine (AG; 100 mg/kg, i.p.), selective NMDAR antagonist MK-801 (0.01 mg/kg, i.p.), and selective NMDAR agonist D-serine (30 mg/kg, i.p.) were injected 15 minutes before lenalidomide.

Results

Lenalidomide at 10 and 20 mg/kg significantly elevated the PTZ-induced seizure thresholds. Interestingly, L-NAME (10 mg/kg, i.p), 7-NI (30 mg/kg, i.p), and AG (100 mg/kg, i.p) reversed the anticonvulsive effect of lenalidomide (10 mg/kg). Moreover, treatment with the NMDAR agonist D-serine (30 mg/kg, i.p.) did not alter the anticonvulsive properties of lenalidomide (10 mg/kg, i.p). However, the NMDAR antagonist MK-801 (0.01 mg/kg, i.p) significantly reversed the anticonvulsive effects of lenalidomide (10 mg/kg).

Conclusions

Our study demonstrated a role for the NMDAR/NO pathway in the anticonvulsive effects of lenalidomide on the PTZ-induced clonic seizures in mice.

Phase 2 Study of Pomalidomide (CC-4047) Monotherapy for Children and Young Adults With Recurrent or Progressive Primary Brain Tumors

Introduction

Treatment of recurrent primary pediatric brain tumors remains a major challenge, with most children succumbing to their disease. We conducted a prospective phase 2 study investigating the safety and efficacy of pomalidomide (POM) in children and young adults with recurrent and progressive primary brain tumors.

Methods

Patients with recurrent and progressive high-grade glioma (HGG), diffuse intrinsic pontine glioma (DIPG), ependymoma, or medulloblastoma received POM 2.6 mg/m²/day (the recommended phase 2 dose [RP2D]) on days 1-21 of a 28-day cycle. A Simon's Optimal 2-stage design was used to determine efficacy. Primary endpoints included objective response (OR) and long-term stable disease (LTSD) rates. Secondary endpoints included duration of response, progression-free survival (PFS), overall survival (OS), and safety.

Results

46 patients were evaluable for response (HGG, n = 19; DIPG, ependymoma, and medulloblastoma, n = 9 each). Two patients with HGG achieved OR or LTSD (10.5% [95% CI, 1.3%-33.1%]; 1 partial response and 1 LTSD) and 1 patient with ependymoma had LTSD (11.1% [95% CI, 0.3%-48.2%]). There were no ORs or LTSD in the DIPG or medulloblastoma cohorts. The median PFS for patients with HGG, DIPG, ependymoma, and medulloblastoma was 7.86, 11.29, 8.43, and 8.43 weeks, respectively. Median OS was 5.06, 3.78, 12.02, and 11.60 months, respectively. Neutropenia was the most common grade 3/4 adverse event.

Conclusions

Treatment with POM monotherapy did not meet the primary measure of success in any cohort. Future studies are needed to evaluate if POM would show efficacy in tumors with specific molecular signatures or in combination with other anticancer agents.

Clinical Trial Registration

ClinicalTrials.gov, identifier NCT03257631; EudraCT, identifier 2016-002903-25.

Phase 1 study of pomalidomide in children with recurrent, refractory, and progressive central nervous system tumors: A Pediatric Brain Tumor Consortium trial

BACKGROUND

Central nervous system (CNS) malignancies are the most common solid tumors among children, and novel therapies are needed to help improve survival. Pomalidomide is an immunomodulatory agent that displays antiangiogenic and cytotoxic activity, making it an appropriate candidate to explore in pediatric CNS tumors.

METHODS

A phase 1 first in pediatric trial of pomalidomide was conducted in children with recurrent, progressive, and refractory CNS tumors. The primary objective was to determine the maximum tolerated dose (MTD) and/or recommended phase 2 dose (RP2D) when given orally once daily for 21 consecutive days of a 28-day cycle. Once the MTD was established, 12 additional patients were enrolled on expansion cohorts based on age and steroid use.

RESULTS

Twenty-nine children were enrolled and 25 were evaluable for dose-limiting toxicity (DLT). The MTD was 2.6 mg/m² (dose level 2). Four DLTs were observed in three patients at dose level 3 (3.4 mg/m² ) includeding grade 3 diarrhea, grade 3 thrombocytopenia, grade 3 lung infection, and grade 4 neutropenia. The most common adverse events were grade 1 and 2 myelosuppression. One patient with an oligodendroglioma had stable disease for nine cycles, and a second patient with an anaplastic pleomorphic xanthoastrocytoma achieved a sustained partial response. Immunologic analyses suggested that pomalidomide triggers immunomodulation.

CONCLUSIONS

The MTD of pomalidomide is 2.6 mg/m² . It was well tolerated, and immune correlates showed a serum immune response. These data led to an industry-sponsored phase 2 trial of pomalidomide monotherapy in children with recurrent brain tumors (NCT03257631).

Current Salvage Treatment Strategies for Younger Children (<10 y of Age) With Progressive Low-grade Glioma After Initial Chemotherapy in North America: A Web-based Survey

Pediatric low-grade gliomas (LGGs) are the most common brain tumors in children. Treatment of pediatric LGG can often be challenging, particularly when not resectable and refractory or recurrent following standard chemotherapy regimens. There is no current accepted standard of care salvage regimen for progressive LGG after the failure of first-line chemotherapy. A web-based survey was distributed to pediatric cancer centers throughout North America to inquire regarding institutional preferences of salvage treatment strategies after initial chemotherapy for LGG in children less than 10 years of age, as well as molecular testing preferences. Highlights from the survey results were as follows: vincristine/carboplatin (VC) and vinblastine (VBL) were the top 2 preferred salvage regimens for non-BRAF-altered pediatric LGG. BRAF and MEK inhibitors were the most preferred salvage regimens for BRAF V600e-mutated and BRAF fusion-positive pediatric LGG, respectively. VC ranked second. As high as 47.8% of North American centers would use conformal radiation for younger children with non-neurofibromatosis type 1 LGG after failing 2 to 3 chemotherapy regimens. Overall, 87% (87%) of North American institutions obtain some type of routine molecular testing for non-neurofibromatosis type 1-associated pediatric LGG cases. Less than 60% of centers obtain routine H3 K27M molecular testing for pediatric LGG with a midline location.

Trametinib-based Treatment of Pediatric CNS Tumors: A Single Institutional Experience

MEK inhibitors are an emerging therapy with increasing use in mitogen-activated protein kinase-driven central nervous system (CNS) tumors. There is limited data regarding efficacy and toxicity in pediatric patients. We report our clinical experience with trametinib-based therapy for the treatment of 14 consecutive pediatric patients with recurrent low-grade glioma (N=11) or high-grade CNS tumors (N=3) with MAP kinase pathway mutations. Patients received trametinib as monotherapy (N=9) or in combination (N=5) with another antineoplastic agent. Nine patients (64%) were progression free during treatment. Five patients showed a partial response, while 4 had stable disease. Two patients (14%) progressed on therapy. All partial responses were in patients with low-grade tumors. The remaining 3 patients were not evaluable due to toxicity limiting duration of therapy. Two of 3 patients with low-grade glioma with leptomeningeal dissemination showed radiographic treatment response. Five patients reported improved clinical symptoms while on trametinib. Adverse events on trametinib-based therapy included dermatologic, mouth sores, fever, gastrointestinal, infection, neutropenia, headache, and fatigue, and were more common in patients using combination therapy. Trametinib-based therapy demonstrated signals of efficacy in our single institutional cohort of pediatric patients with mitogen-activated protein kinase-driven CNS tumors. Our observations need to be confirmed in a clinical trial setting.

A phase I trial of lenalidomide and radiotherapy in children with diffuse intrinsic pontine gliomas or high-grade gliomas

PURPOSE

This study was performed to determine the maximum tolerated dose (MTD) or recommended phase 2 dose (RP2D) of the immunomodulatory agent, lenalidomide, when administered daily during 6 weeks of radiation therapy to children with newly diagnosed diffuse intrinsic pontine glioma (DIPG) or high-grade glioma (HGG) PATIENTS & METHODS: Children and young adults < 22 years of age with newly diagnosed disease and no prior chemotherapy or radiation therapy were eligible. Children with HGG were required to have an inoperable or incompletely resected tumor. Eligible patients received standard radiation therapy to a prescription dose of 54-59.4 Gy, with concurrent administration of lenalidomide daily during radiation therapy in a standard 3 + 3 Phase I dose escalation design. Following completion of radiation therapy, patients had a 2-week break followed by maintenance lenalidomide at 116 mg/m²/day × 21 days of a 28-day cycle.

RESULTS

Twenty-nine patients (age range 4-19 years) were enrolled; 24 were evaluable for dose finding (DIPG, n = 13; HGG, n = 11). The MTD was not reached at doses of lenalidomide up to 116 mg/m²/day. Exceptional responses were noted in DIPG and malignant glioma (gliomatosis cerebri) notably at higher dose levels and at higher steady state plasma concentrations. The primary toxicity was myelosuppression.

CONCLUSION

The RP2D of lenalidomide administered daily during radiation therapy is 116 mg/m²/day. Children with malignant gliomas tolerate much higher doses of lenalidomide during radiation therapy compared to adults. This finding is critical as activity was observed primarily at higher dose levels suggesting a dose response.

A systematic review of ongoing clinical trials in optic pathway gliomas

INTRODUCTION

Optic pathway gliomas (OPGs), also known as Visual Pathway Gliomas, are insidious, debilitating tumours. They are most commonly WHO grade 1 pilocytic astrocytomas and frequently occur in patients with neurofibromatosis type 1. The location of OPGs within the optic pathway typically precludes complete resection or optimal radiation dosing, hence outcomes remain poor compared to many other low-grade gliomas. The aim of this systematic review was to formulate a comprehensive list of all current ongoing clinical trials that are specifically looking at clinical care of OPGs in order to identify trends in current research and provide an overview to guide future research efforts.

METHODS

This systematic review was conducted in line with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. The Cochrane Controlled Register of Trials (CENTRAL) and ClinicalTrials.gov were searched. Inclusion and exclusion criteria were applied and final results were reviewed.

RESULTS

501 clinical trials were identified with the search strategy. All were screened and eligible studies extracted and reviewed. This yielded 36 ongoing clinical trials, 27 of which were pharmacological agents in phase I-III. The remaining trials were a mixture of biological agents, radiation optimisation, diagnostic imaging, surgical intervention, and a social function analysis.

CONCLUSION

OPG is a complex multifaceted disease, and advances in care require ongoing research efforts across a spectrum of different research fields. This review provides an update on the current state of research in OPG and summarises ongoing trials.

Antitumor effect of lenalidomide in malignant glioma cell lines

Glioblastoma is a malignant brain tumor exhibiting highly aggressive proliferation and invasion capacities. Despite treatment by aggressive surgical resection and adjuvant therapy including temozolomide and radiation therapy, patient prognosis remains poor. Lenalidomide, a derivative of thalidomide, is known to be an immunomodulatory agent that has been used to treat hematopoietic malignancies. There are numerous studies revealing an antitumor effect of lenalidomide in hematopoietic cells, but not in glioma cells. The present study aimed to demonstrate the antitumor effect of lenalidomide on malignant glioma cell lines. The growth inhibition of malignant glioma cells (A-172, AM-38, T98G, U-138MG, U-251MG, and YH-13) by lenalidomide was assessed using a Coulter counter. The mechanism of the antitumor effect of lenalidomide was examined employing a fluorescence-activated cell sorter, western blot analysis, and quantitative real-time reverse transcriptional polymerase chain reaction (RT-qPCR) in malignant glioma cell lines (A-172, AM-38). The results revealed that the number of malignant glioma cells was decreased in a concentration-dependent manner by lenalidomide. DNA flow cytometric analysis demonstrated an increase in the ratio of cells at the G₀/G₁ phase following lenalidomide treatment. Western blot analysis and RT-qPCR revealed that p53 activation and the expression of p21 were increased in glioma cells treated with lenalidomide. Western blot analysis revealed that cleavage of PARP did not occur; however, increased expression of Bax protein, cleavage of caspase-9 and cleavage of caspase-3 were confirmed. Analysis by FACS also supported the conclusion that little apoptosis induction occurred following lenalidomide treatment of malignant glioma cell lines. In conclusion, lenalidomide exerts an antitumor effect on glioma cells due to alterations in cell cycle distribution.

Neuroinflammation as a Factor of Neurodegenerative Disease: Thalidomide Analogs as Treatments

Neuroinflammation is initiated when glial cells, mainly microglia, are activated by threats to the neural environment, such as pathogen infiltration or neuronal injury. Although neuroinflammation serves to combat these threats and reinstate brain homeostasis, chronic inflammation can result in excessive cytokine production and cell death if the cause of inflammation remains. Overexpression of tumor necrosis factor-α (TNF-α), a proinflammatory cytokine with a central role in microglial activation, has been associated with neuronal excitotoxicity, synapse loss, and propagation of the inflammatory state. Thalidomide and its derivatives, termed immunomodulatory imide drugs (IMiDs), are a class of drugs that target the 3'-untranslated region (3'-UTR) of TNF-α mRNA, inhibiting TNF-α production. Due to their multi-potent effects, several IMiDs, including thalidomide, lenalidomide, and pomalidomide, have been repurposed as drug treatments for diseases such as multiple myeloma and psoriatic arthritis. Preclinical studies of currently marketed IMiDs, as well as novel IMiDs such as 3,6'-dithiothalidomide and adamantyl thalidomide derivatives, support the development of IMiDs as therapeutics for neurological disease. IMiDs have a competitive edge compared to similar anti-inflammatory drugs due to their blood-brain barrier permeability and high bioavailability, with the potential to alleviate symptoms of neurodegenerative disease and slow disease progression. In this review, we evaluate the role of neuroinflammation in neurodegenerative diseases, focusing specifically on the role of TNF-α in neuroinflammation, as well as appraise current research on the potential of IMiDs as treatments for neurological disorders.

Development of a physiologically based pharmacokinetic model for intravenous lenalidomide in mice

PURPOSE

Lenalidomide is used widely in B-cell malignancies for its immunomodulatory activity. It is primarily eliminated via the kidneys, with a significant proportion of renal elimination attributed to active processes. Lenalidomide is a weak substrate of P-glycoprotein (P-gp), though it is unclear whether P-gp is solely responsible for lenalidomide transport. This study aimed to determine whether the current knowledge of lenalidomide was sufficient to describe the pharmacokinetics of lenalidomide in multiple tissues.

METHODS

A physiologically based pharmacokinetic model was developed using the Open Systems Pharmacology Suite to explore the pharmacokinetics of lenalidomide in a variety of tissues. Data were available for mice dosed intravenously at 0.5, 1.5, 5, and 10 mg/kg, with concentrations measured in plasma, brain, heart, kidney, liver, lung, muscle, and spleen. P-gp expression and activity were sourced from the literature.

RESULTS

The model predictions in plasma, liver, and lung were representative of the observed data (median prediction error 13%, - 10%, and 30%, respectively, with 90% confidence intervals including zero), while other tissue predictions showed sufficient similarity to the observed data. Contrary to the data, model predictions for the brain showed no drug reaching brain tissue when P-gp was expressed at the blood-brain barrier. The data were better described by basolateral transporters at the intracellular wall. Local sensitivity analysis showed that transporter activity was the most sensitive parameter in these models for exposure.

CONCLUSION

As P-gp transport at the blood-brain barrier did not explain the observed brain concentrations alone, there may be other transporters involved in lenalidomide disposition.

Pediatric Brainstem Gliomas: A Retrospective Study of 180 Patients from the SEER Database

BACKGROUND/AIMS

Large population-based studies are needed to assess the epidemiology and survival risk factors associated with pediatric brainstem gliomas. This retrospective study explores factors that may influence survival in this population.

METHODS

Utilizing the SEER database, the authors retrospectively assessed survival in histologically confirmed brainstem gliomas in patients aged 17 and younger. Survival was described with Kaplan-Meyer curves and multivariate regression analysis.

RESULTS

This analysis of 180 cases showed that age (hazard ratio [HR] 1.04, 95% CI 0.96-1.14, p = 0.34), non-white race (HR 1.00, 95% CI 0.35-2.85 p > 0.99), distant or invasive extension of the tumor (HR 0.4, 95% CI 0.08-2.53, p = 0.37), and radiation therapy (HR 1.27, 95% CI 0.52-3.11, p = 0.61) were not associated with decreased survival. High-grade tumor status (HR 8.64, 95% CI 3.49-21.41, p < 0.001) was associated with decreased survival. Partial resection (HR 0.11, 95% CI 0.04-0.30, p < 0.001) and gross-total resection (HR 0.03, 95% CI 0.01-0.14, p < 0.001) were associated with improved survival.

CONCLUSIONS

High-grade brainstem gliomas have a worse prognosis. Early diagnosis and surgery appear to be associated with improved survival, while the role of radiation is unclear.

A First-in-Human Study of Novel Cereblon Modulator Avadomide (CC-122) in Advanced Malignancies

PURPOSE

Avadomide is a novel, small-molecule therapeutic agent that modulates cereblon E3 ligase activity and exhibits potent antitumor and immunomodulatory activities. This first-in-human phase I study (NCT01421524) evaluated the safety and clinical activity of avadomide in patients with advanced solid tumors, non-Hodgkin lymphoma (NHL), and multiple myeloma.

PATIENTS AND METHODS

Thirty-four patients were treated with avadomide in 7 dose-escalation cohorts using a 3 + 3 design (0.5-3.5 mg, 28-day continuous dosing cycles). The primary objectives were to determine the dose-limiting toxicity (DLT), nontolerated dose (NTD), maximum tolerated dose (MTD), recommended phase II dose, and pharmacokinetics of avadomide. The secondary objective was to determine preliminary avadomide efficacy. Exploratory objectives included evaluation of pharmacodynamic effects of avadomide.

RESULTS

DLTs were reported in 2 patients, and grade ≥3 treatment-emergent adverse events (TEAEs) occurred in 14 patients (41%). The most common TEAEs (≥15%) were fatigue, neutropenia, and diarrhea. The NTD and MTD were 3.5 and 3.0 mg, respectively. Of 5 patients with NHL, 1 achieved a complete response, and 2 had partial responses. Although no objective responses were observed in patients with solid tumors, 5 of 6 patients with brain cancer experienced nonprogression of ≥6 months. A dose-dependent relationship between Aiolos degradation in peripheral B and T cells occurred within 5 hours of the first dose of avadomide administered, starting at 0.5 mg.

CONCLUSIONS

Avadomide monotherapy demonstrated acceptable safety and favorable pharmacokinetics in patients with solid tumors, NHL, and multiple myeloma. In addition, 3 objective responses were observed in NHL.

Lack of value of juvenile animal toxicity studies for supporting the safety of pediatric oncology phase I trials

Toxicity studies in juvenile animals (JAS) are sometimes performed to support clinical trials in pediatric oncology patients, and there are differing conclusions on the value of JAS for pediatric drug development. This manuscript provides a review of the pediatric clinical data for 25 molecularly-targeted and 4 biologic anticancer therapeutics. Other publications that evaluated the value of JAS in pediatric drug development focus on differences in toxicity between juvenile animals and adult animals. The present paper examines pediatric-specific clinical findings to focus on dose setting in pediatric oncology patients and safety monitoring in terms of the potential value of JAS. Our assessment demonstrates that pediatric starting doses were safe for all 29 therapeutics examined in that no life-threatening toxicities occurred in the first cohort, and overall the ratio of the pediatric maximum tolerated dose (MTD) to the recommended adult dose was close to 1. In addition, the 4 serious adverse events (SAEs) that weren't detectable with standard monitoring plans for pediatric oncology trials would not have been detectable in a standard JAS. This review demonstrates that safe starting doses in pediatric oncology patients for these therapeutics could have been solely based on adult doses without any knowledge of findings in JAS.

The possible role of maintenance treatment for primary central nervous system lymphoma

Primary central nervous system lymphoma (PCNSL) is a rare and aggressive brain tumor. The prognosis is poor, with high rates of relapse and disease progression after treatment. In addition, PCNSL affects a largely older population, so that a significant proportion of patients are ineligible for intensive therapies and high-dose chemotherapy. The elderly patients are also susceptible to the accelerated and detrimental cognitive side effects of whole-brain irradiation which is an alternative consolidation to high-dose chemotherapy. Maintenance therapy has been shown to be a promising strategy to prolong remission time in other hematopoietic malignancies. Herein, we discuss the place of maintenance treatment in PCNSL in view of perspective obtained from hematological malignancies and non-Hodgkin's lymphoma.

Medulloblastoma in children and adolescents: a systematic review of contemporary phase I and II clinical trials and biology update

Survival rates for patients with medulloblastoma have improved in the last decades but for those who relapse outcome is dismal and new approaches are needed. Emerging drugs have been tested in the last two decades within the context of phase I/II trials. In parallel, advances in genetic profiling have permitted to identify key molecular alterations for which new strategies are being developed. We performed a systematic review focused on the design and outcome of early-phase trials evaluating new agents in patients with relapsed medulloblastoma. PubMed, clinicaltrials.gov, and references from selected studies were screened to identify phase I/II studies with reported results between 2000 and 2015 including patients with medulloblastoma aged <18 years. A total of 718 studies were reviewed and 78 satisfied eligibility criteria. Of those, 69% were phase I; 31% phase II. Half evaluated conventional chemotherapeutics and 35% targeted agents. Overall, 662 patients with medulloblastoma/primitive neuroectodermal tumors were included. The study designs and the response assessments were heterogeneous, limiting the comparisons among trials and the correct identification of active drugs. Median (range) objective response rate (ORR) for patients with medulloblastoma in phase I/II studies was 0% (0-100) and 6.5% (0-50), respectively. Temozolomide containing regimens had a median ORR of 16.5% (0-100). Smoothened inhibitors trials had a median ORR of 8% (3-8). Novel drugs have shown limited activity against relapsed medulloblastoma. Temozolomide might serve as backbone for new combinations. Novel and more homogenous trial designs might facilitate the development of new drugs.

Pediatric low-grade gliomas: implications of the biologic era

For the past decade, it has been recognized that pediatric low-grade gliomas (LGGs) and glial-neuronal tumors carry distinct molecular alterations with resultant aberrant intracellular signaling in the Ras-mitogen-activated protein kinase pathway. The conclusions and recommendations of a consensus conference of how best to integrate the growing body of molecular genetic information into tumor classifications and, more importantly, for future treatment of pediatric LGGs are summarized here. There is uniform agreement that molecular characterization must be incorporated into classification and is increasingly critical for appropriate management. Molecular-targeted therapies should be integrated expeditiously, but also carefully into the management of these tumors and success measured not only by radiographic responses or stability, but also by functional outcomes. These trials need to be carried out with the caveat that the long-term impact of molecularly targeted therapy on the developing nervous system, especially with long duration treatment, is essentially unknown.

Central Nervous System Prophylaxis for Aggressive B-cell Lymphoma: Who, What, and When?

Central nervous system (CNS) relapse of aggressive B-cell lymphoma is a rare but serious complication with poor survival. Different approaches have been used to define risks factors for CNS relapse and establish prophylactic measures. Although patients with low or intermediate risk of CNS relapse should not undergo special diagnostic or therapeutic measures, CNS MRI as well as cytology and flow cytometry of the cerebrospinal fluid are suggested for high-risk patients (and patients with testicular involvement) at diagnosis, and prophylactic high-dose methotrexate in patients without proven CNS involvement. Future risk and treatment models may include molecular features and new treatment options.

A comparison of safety and efficacy of cytotoxic versus molecularly targeted drugs in pediatric phase I solid tumor oncology trials

BACKGROUND

Prior reviews of phase I pediatric oncology trials involving primarily cytotoxic agents have reported objective response rates (ORRs) and toxic death rates of 7.9-9.6% and 0.5%, respectively. These data may not reflect safety and efficacy in phase I trials of molecularly targeted (targeted) drugs.

METHODS

A systematic review of pediatric phase I solid tumor trials published in 1990-2013 was performed. The published reports were evaluated for patient characteristics, toxicity information, and response numbers.

RESULTS

A total of 143 phase I pediatric clinical trials enrolling 3,896 children involving 53 targeted and 48 cytotoxic drugs were identified. A meta-analysis demonstrated that the ORR is 2.1-fold higher with cytotoxic drugs (0.066 vs. 0.031 per subject; P = 0.007). By contrast, the pooled estimate of the stable disease rate (SDR) is similar for cytotoxic and targeted drugs (0.2 vs. 0.23 per subject; P = 0.27).  The pooled estimate of the dose-limiting toxicity rate is 1.8-fold larger with cytotoxic drugs (0.24 vs. 0.13 per subject; P = 0.0003). The hematologic grade 3-4 (G3/4) toxicity rate is 3.6-fold larger with cytotoxic drugs (0.43 vs. 0.12 per treatment course; P = 0.0001); however, the nonhematologic G3/4 toxicities and toxic deaths occur at similar rates for cytotoxic and targeted drugs.

CONCLUSIONS

In phase I pediatric solid tumor trials, ORRs were significantly higher for cytotoxic versus targeted agents. SDRs were similar in targeted and cytotoxic drug trials. Patients treated with cytotoxic agents were more likely to experience hematologic G3/4 toxicities than those patients receiving targeted drugs.

Dose-finding designs for trials of molecularly targeted agents and immunotherapies

Recently, there has been a surge of early phase trials of molecularly targeted agents (MTAs) and immunotherapies. These new therapies have different toxicity profiles compared to cytotoxic therapies. MTAs can benefit from new trial designs that allow inclusion of low-grade toxicities, late-onset toxicities, addition of an efficacy endpoint, and flexibility in the specification of a target toxicity probability. To study the degree of adoption of these methods, we conducted a Web of Science search of articles published between 2008 and 2014 that describe phase 1 oncology trials. Trials were categorized based on the dose-finding design used and the type of drug studied. Out of 1,712 dose-finding trials that met our criteria, 1,591 (92.9%) utilized a rule-based design, and 92 (5.4%; range 2.3% in 2009 to 9.7% in 2014) utilized a model-based or novel design. Over half of the trials tested an MTA or immunotherapy. Among the MTA and immunotherapy trials, 5.8% used model-based methods, compared to 3.9% and 8.3% of the chemotherapy or radiotherapy trials, respectively. While the percentage of trials using novel dose-finding designs has tripled since 2007, the adoption of these designs continues to remain low.

Clinical Pharmacokinetics and Pharmacodynamics of Lenalidomide

Lenalidomide is a lead therapeutic in multiple myeloma and deletion 5q myelodysplastic syndromes and shows promising activities in other hematologic malignancies. This article presents a comprehensive review of the clinical pharmacokinetics and pharmacodynamics of lenalidomide. Oral lenalidomide is rapidly and highly absorbed (>90 % of dose) under fasting conditions. Food affects oral absorption, reducing area under the concentration-time curve (AUC) by 20 % and maximum concentration (C max) by 50 %. The increase in AUC and C max is dose proportional, and interindividual variability in plasma exposure is low to moderate. Lenalidomide distributes into semen but is undetectable 3 days after stopping treatment. Biotransformation of lenalidomide in humans includes chiral inversion, trivial hydroxylation, and slow non-enzymatic hydrolysis. Approximately 82 % of an oral dose is excreted as lenalidomide in urine within 24 h. Lenalidomide has a short half-life (3-4 h) and does not accumulate in plasma upon repeated dosing. Its pharmacokinetics are consistent across patient populations, regardless of the type of hematologic malignancy. Renal function is the only important factor affecting lenalidomide plasma exposure. Lenalidomide has no QT prolongation risk at approved doses, and higher plasma exposure to lenalidomide is associated with increased risk of neutropenia and thrombocytopenia. Despite being a weak substrate of P-glycoprotein (P-gp) in vitro, lenalidomide does not have clinically significant pharmacokinetic interactions with P-gp substrates/inhibitors in controlled studies. The AUC-matched dose adjustment is recommended for patients with renal impairment at the start of therapy. No dose adjustment for lenalidomide is needed on the basis of age, ethnicity, mild hepatic impairment, or drug-drug interactions.

Synthesis and Biological Evaluation of Novel Aromatic Imide-Polyamine Conjugates

Three types of conjugates in which aromatic imide scaffolds were coupled to diverse amine/polyamine motifs were synthesized, and their antitumor activities were evaluated in vitro and in vivo. Results showed that the conjugate 11e of 1,8-naphthilimide with spermine had pronounced effects on inhibiting tumor cell proliferation and inducing tumor cell apoptosis via ROS-mediated mitochondrial pathway. The in vivo assays on three H22 tumor transplant models revealed that compound 11e exerted potent ability in preventing lung cancer metastasis and extending lifespan. Furthermore, the efficacy of 11e in inhibiting tumor growth and improving body weight index were better than that of positive control, amonafide. Our study demonstrates that compound 11e is a valuable lead compound for further investigation.

Antigen-specific immunoreactivity and clinical outcome following vaccination with glioma-associated antigen peptides in children with recurrent high-grade gliomas: results of a pilot study

Recurrent high-grade gliomas (HGGs) of childhood have an exceedingly poor prognosis with current therapies. Accordingly, new treatment approaches are needed. We initiated a pilot trial of vaccinations with peptide epitopes derived from glioma-associated antigens (GAAs) overexpressed in these tumors in HLA-A2+ children with recurrent HGG that had progressed after prior treatments. Peptide epitopes for three GAAs (EphA2, IL13Rα2, survivin), emulsified in Montanide-ISA-51, were administered subcutaneously adjacent to intramuscular injections of poly-ICLC every 3 weeks for 8 courses, followed by booster vaccines every 6 weeks. Primary endpoints were safety and T-cell responses against the GAA epitopes, assessed by enzyme-linked immunosorbent spot (ELISPOT) analysis. Treatment response was evaluated clinically and by magnetic resonance imaging. Twelve children were enrolled, 6 with glioblastoma, 5 with anaplastic astrocytoma, and one with malignant gliomatosis cerebri. No dose-limiting non-CNS toxicity was encountered. ELISPOT analysis, in ten children, showed GAA responses in 9: to IL13Rα2 in 4, EphA2 in 9, and survivin in 3. One child had presumed symptomatic pseudoprogression, discontinued vaccine therapy, and responded to subsequent treatment. One other child had a partial response that persisted throughout 2 years of vaccine therapy, and continues at >39 months. Median progression-free survival (PFS) from the start of vaccination was 4.1 months and median overall survival (OS) was 12.9 months. 6-month PFS and OS were 33 and 73 %, respectively. GAA peptide vaccination in children with recurrent malignant gliomas is generally well tolerated, and has preliminary evidence of immunological and modest clinical activity.

Immune responses and outcome after vaccination with glioma-associated antigen peptides and poly-ICLC in a pilot study for pediatric recurrent low-grade gliomas

BACKGROUND

Low-grade gliomas (LGGs) are the most common brain tumors of childhood. Although surgical resection is curative for well-circumscribed superficial lesions, tumors that are infiltrative or arise from deep structures are therapeutically challenging, and new treatment approaches are needed. Having identified a panel of glioma-associated antigens (GAAs) overexpressed in these tumors, we initiated a pilot trial of vaccinations with peptides for GAA epitopes in human leukocyte antigen-A2+ children with recurrent LGG that had progressed after at least 2 prior regimens.

METHODS

Peptide epitopes for 3 GAAs (EphA2, IL-13Rα2, and survivin) were emulsified in Montanide-ISA-51 and administered subcutaneously adjacent to intramuscular injections of polyinosinic-polycytidylic acid stabilized by lysine and carboxymethylcellulose every 3 weeks for 8 courses, followed by booster vaccines every 6 weeks. Primary endpoints were safety and T-lymphocyte responses against GAA epitopes. Treatment response was evaluated clinically and by MRI.

RESULTS

Fourteen children were enrolled. Other than grade 3 urticaria in one child, no regimen-limiting toxicity was encountered. Vaccination induced immunoreactivity to at least one vaccine-targeted GAA in all 12 evaluable patients: to IL-13Rα2 in 3, EphA2 in 11, and survivin in 3. One child with a metastatic LGG had asymptomatic pseudoprogression noted 6 weeks after starting vaccination, followed by dramatic disease regression with >75% shrinkage of primary tumor and regression of metastatic disease, persisting >57 months. Three other children had sustained partial responses, lasting >10, >31, and >45 months, and one had a transient response.

CONCLUSIONS

GAA peptide vaccination in children with recurrent LGGs is generally well tolerated, with preliminary evidence of immunological and clinical activity.

Complications from pharmacotherapy

The pharmacotherapy management of cancers of the nervous system has significant overlap with systemic solid cancers that may utilize similar drugs or agents. There is however a unique aspect related to central nervous system (CNS) cancers where therapies directed against a malignant process may have enhanced toxicities or toxicities unique to the CNS. In addition, many agents used to treat CNS malignancies have unique CNS toxicities that may require a specific intervention. This chapter attempts to review conventional and biologic therapies utilized for CNS malignancies and characterize expected and, if known, unique toxicities.

Review of low-grade gliomas in children--evolving molecular era and therapeutic insights

Low-grade gliomas are the commonest brain tumor in children comprising heterogeneous pathological entities. Though the overall prognosis is good, unresectable, and recurrent or progressive tumors in eloquent areas of the brain remain major therapeutic challenge even with advances in chemotherapeutic strategies. With the evolving surge of molecular data, improved understanding of the biology of these tumors is now perceivable that could provide insights into novel therapies. We hope the new era will enable us to profile comprehensive histopathological/molecular classification and prognostic molecular markers in these tumors and guide us to tailor optimal targeted therapy.

Improving outcomes for neurofibromatosis 1-associated brain tumors

Children and adults with neurofibromatosis type 1 (NF1) are predisposed to developing CNS tumors, including optic pathway gliomas (OPGs), brainstem gliomas (BSGs) and high-grade gliomas. Although current first-line treatments for low-grade gliomas (OPGs and BSGs) may prevent further tumor growth, they rarely result in restoration of the associated visual or neurological deficits. The availability of accurate small-animal models of NF1-associated brain tumors has established tractable experimental platforms for the discovery and evaluation of promising therapeutic agents. On the basis of these preclinical studies, biologically targeted agents are now being evaluated in children with NF1-associated low-grade brain tumors. Collectively, these models have also begun to reveal potential neuroprotective and risk assessment strategies for this brain tumor-prone population.

Advances in the management of low-grade gliomas

Low-grade gliomas (LGGs) represent the most common childhood brain tumors and are a histologically heterogenous group of tumors. Most LGGs are surgically resectable with excellent 10-year overall survival outcomes of more than 90 % with surgery alone. Tumors not amenable to surgical resection and those with an aggressive biology are more challenging to treat. Conventional radiotherapy is a more efficacious method of long-term tumor control than chemotherapy. However, radiation is associated with significant cognitive, endocrine, and cerebrovascular late effects, making chemotherapy an often-preferred modality over radiotherapy, especially in younger children. Multiple chemotherapy regimens have been evaluated over the past few decades with comparable survival outcomes and differing toxicity profiles. Newer regimens containing antiangiogenic agents also show promise. Recent molecular studies have implicated the BRAF oncogene, a key regulator of the MAPK pathway, and the AKT/mTOR pathway in pediatric LGG tumorigenesis. This has opened up promising new avenues for targeted therapy, with many agents currently under investigation.

Simultaneous determination of dexamethasone and lenalidomide in rat plasma by solid phase extraction and ultra-performance liquid chromatography-tandem mass spectrometry: application to pharmacokinetic studies

Determination of dexamethasone and lenalidomide in plasma by SPE and UPLC-MS/MS for the purpose of TDM: application to pharmacokinetic studies.

Targeted therapy in pediatric low-grade glioma

Collectively, pediatric low-grade gliomas account for most brain tumors reported in children. Surgery is typically curable for operable lesions. However, more effective therapies are required for inaccessible tumors, both to overcome refractory disease and to minimize the toxicity associated with conventional adjuvant chemotherapy and radiotherapy regimens. Recent years have witnessed rapid improvements in our understanding of the molecular pathogenesis of several childhood tumors, including low-grade gliomas. As a result, several novel compounds targeting and inhibiting critical components of molecular signaling pathways purported to be overactive in the disease have been developed. This article summarizes the most recent literature evaluating such novel targeted agents in childhood low-grade gliomas.

Pediatric phase II trials of poly-ICLC in the management of newly diagnosed and recurrent brain tumors

Brain tumors are the most common solid tumor diagnosed in childhood that account for significant morbidity and mortality. New therapies are urgently needed; hence, we conducted the first ever prospective open-label phase II trials of the biological response modifier, poly-ICLC, in children with brain tumors. Poly-ICLC is a synthetic double-stranded RNA that has direct antiviral, antineoplastic, and immune adjuvant effects. A total of 47 children representing a variety of brain tumor histopathologic subtypes were treated with poly-ICLC. On the basis of the results of the initial phase II trial, an expanded prospective phase II trial in low-grade glioma (LGG) has been initiated. MRI was used to acquire volume-based measures of tumor response. No dose-limiting toxicities have been observed. In the initial study 3 of 12 subjects with progressive high-grade gliomas (HGGs) responded, and 2 of 4 children with progressive LGG experienced stable disease for 18 to 24 months. In the follow-up LGG phase II study, 2 of 5 LGG patients were stable over 18 months, with 1 stable for 6 months. Overall 5 of 10 LGG patients have responded. On the basis of low toxicity and the promising LGG response, poly-ICLC may be effective for childhood LGG, and the results justify biomarker studies for personalization of poly-ICLC as a single agent or adjuvant.