Central Nervous System Penetration Research Articles

The emergence of letermovir and maribavir drug-resistant mutations: from clinical trials to real-world studies.

Cytomegalovirus (CMV) infection is associated with severe clinical disease and high morbidity in immunocompromised hosts. Letermovir and maribavir, are two recently developed antiviral drugs used in the prevention and treatment of resistant and refractory CMV. Following the publication of landmark randomized trials and increased use, both clinical trial data and real-world experience has reported the development of antiviral drug resistance. The aim of this review was to comprehensively review the published literature on letermovir and maribavir drug resistance and to describe the clinical scenarios in which they may emerge. For letermovir, the most frequently detected resistance mutations occur in the UL56 gene (C325Y/W/F) and confer total resistance. Maribavir resistance mutations most often occur in the UL97 gene and resistance-associated variants (RAVs) T409M, H411Y, C480F have all been detected. The clinical context in which letermovir and maribavir resistance occurs include high viral loads at initiation, intensified immunosuppression, subtherapeutic drug exposure because of poor adherence, drug interactions, and inadequate central nervous system (CNS) penetration. Emergence of resistance mutations generally occurs within the first 3 months of initiation. The detection of letermovir and maribavir resistance mutations highlights an ongoing clinical challenge in the management of CMV.

Molecular docking analysis of Salvia sclarea flower extracts evaluated for protein target affinity based on different extraction methods

AbstractThis study evaluates the antioxidant activity and total phenolic, flavonoid, flavonol, and tannin contents of extracts obtained from the flower parts of Salvia sclarea using different extraction methods, such as maceration and rotavapor (RE). The results indicate that the maceration method yields extracts with higher antioxidant activity compared to the rotavapor method (DPPH IC50: 260.70 ± 65.41 mg/mL vs. 345.48 ± 27.91 mg/mL). Additionally, the maceration method produces higher values in terms of total phenolic (26.4 ± 7.78 mg GAE/g extract), flavonoid (10.44 ± 0.21 mg QE/g extract), flavonol (9.20 ± 0.84 mg QE/g extract), and tannin contents (8.36 ± 0.39 mg GAE/g extract), whereas the RE method shows lower values (phenolics: 19.8 ± 3.31 mg GAE/g extract, flavonoids: 10.35 ± 0.35 mg QE/g extract, flavanol's: 5.45 ± 0.01 mg QE/g extract, and tannins: 7.72 ± 0.10 mg GAE/g extract). The gas chromatography–mass spectrometry (GC–MS) analysis of the extracts identified various bioactive compounds. Molecular docking studies revealed that Terpinen‐4‐ol obtained through maceration exhibits a strong binding affinity to a specific protein target, indicating potential biological activity. The predicted pharmacokinetic (ADME (absorption, distribution, metabolism, and excretion)) parameters for Terpinen‐4‐ol suggest favorable absorption and central nervous system (CNS) penetration, while Squalene obtained through maceration shows different pharmacokinetic properties. S. sclarea highlights significant antioxidant potential and provides insight into the bioactive compounds obtained through different extraction methods. To further investigate the potential biological interactions arising from these differences, molecular docking studies were conducted.

Preclinical evaluation of targeted therapies for central nervous system metastases.

The central nervous system (CNS) represents a site of sanctuary for many metastatic tumors when systemic therapies that control the primary tumor cannot effectively penetrate intracranial lesions. Non-small cell lung cancers (NSCLCs) are the most likely of all neoplasms to metastasize to the brain, with up to 60% of patients developing CNS metastases during the disease process. Targeted therapies such as tyrosine kinase inhibitors (TKIs) have helped reduce lung cancer mortality but vary considerably in their capacity to control CNS metastases. The ability of these therapies to effectively target lesions in the CNS depends on several of their pharmacokinetic properties, including blood-brain barrier permeability, affinity for efflux transporters, and binding affinity for both plasma and brain tissue. Despite the existence of numerous preclinical models with which to characterize these properties, many targeted therapies have not been rigorously tested for CNS penetration during the discovery process, whereas some made it through preclinical testing despite poor brain penetration kinetics. Several TKIs have now been engineered with the characteristics of CNS-penetrant drugs, with clinical trials proving these efforts fruitful. This Review outlines the extent and variability of preclinical evidence for the efficacy of NSCLC-targeted therapies, which have been approved by the US Food and Drug Administration (FDA) or are in development, for treating CNS metastases, and how these data correlate with clinical outcomes.

Advances in Intrathecal Nanoparticle Delivery: Targeting the Blood-Cerebrospinal Fluid Barrier for Enhanced CNS Drug Delivery.

The blood-cerebrospinal fluid barrier (BCSFB) tightly regulates molecular exchanges between the bloodstream and cerebrospinal fluid (CSF), creating challenges for effective central nervous system (CNS) drug delivery. This review assesses intrathecal (IT) nanoparticle (NP) delivery systems that aim to enhance drug delivery by circumventing the BCSFB, complementing approaches that target the blood-brain barrier (BBB). Active pharmaceutical ingredients (APIs) face hurdles like restricted CNS distribution and rapid clearance, which diminish the efficacy of IT therapies. NPs can be engineered to extend drug circulation times, improve CNS penetration, and facilitate sustained release. This review discusses key pharmacokinetic (PK) parameters essential for the effectiveness of these systems. NPs can quickly traverse the subarachnoid space and remain within the leptomeninges for extended periods, often exceeding three weeks. Some designs enable deeper brain parenchyma penetration. Approximately 80% of NPs in the CSF are cleared through the perivascular glymphatic pathway, with microglia-mediated transport significantly contributing to their paravascular clearance. This review synthesizes recent progress in IT-NP delivery across the BCSFB, highlighting critical findings, ongoing challenges, and the therapeutic potential of surface modifications and targeted delivery strategies.

Candida parapsilosis intracerebral abscess and intralesional amphotericin B: a novel treatment approach to a rare infection. Illustrative case.

Candida parapsilosis has been implicated in central nervous system (CNS) infections (i.e., meningitis or ventriculitis) but has not been previously reported to cause intracerebral abscesses. CNS infections secondary to C. parapsilosis are notoriously difficult to treat due to the poor CNS penetration of amphotericin B. Historically, intraventricular amphotericin B has been used to treat C. parapsilosis ventriculitis. A 15-year-old female with no comorbidities presented with nonresolving headaches, photophobia, fevers, and meningism. Computed tomography (CT) of the brain revealed a right frontal abscess. After multiple drainage surgeries, subsequent CT scans showed reaccumulation of her abscess. C. parapsilosis was cultured, and the patient was then taken to the operating room where an external ventricular drain catheter was successfully placed within the abscess cavity. Pus was repeatedly aspirated, followed by the instillation of intralesional amphotericin B twice a day for 2 weeks. The patient's clinical condition improved substantially with complete resolution of symptoms, improvement of infective markers, and resolution of radiological features of the abscess. Follow-up of the patient revealed the absence of symptoms and image characteristics of abscess on CT 3 months posttreatment. Intralesional amphotericin B is a novel but effective treatment of C. parapsilosis intracerebral abscess, an organism not previously described as a cause of intracerebral abscesses. https://thejns.org/doi/10.3171/CASE2484.

RET Inhibitors in RET Fusion-Positive Lung Cancers: Past, Present, and Future.

While activating RET fusions are identified in various cancers, lung cancer represents the most common RET fusion-positive tumor. The clinical drug development of RET inhibitors in RET fusion-positive lung cancers naturally began after RET fusions were first identified in patient tumor samples in 2011, and thereafter paralleled drug development in RET fusion-positive thyroid cancers. Multikinase inhibitors were initially tested with limited efficacy and substantial toxicity. RET inhibitors were then designed with improved selectivity, central nervous system penetrance, and activity against RET fusions and most RET mutations, including resistance mutations. Owing their success to these rationally designed features, the first-generation selective RET tyrosine kinase inhibitors (TKIs) had higher response rates, more durable disease control, and an improved safety profile compared to the multikinase inhibitors. This led to lung and thyroid cancer, and later tumor-agnostic regulatory approvals. While next-generation RET TKIs were designed to abrogate uncommon on-target (e.g., solvent front mutation) resistance to selpercatinib and pralsetinib, many of these drugs lacked the selectivity of the first-generation TKIs, raising the question of what the future holds for drug development in RET-dependent cancers.

Delocalized quinolinium-macrocyclic peptides, an atypical chemotype for CNS penetration.

Macrocyclic drugs can address an increasing range of molecular targets but enabling central nervous system (CNS) access to these drugs has been viewed as an intractable problem. We designed and synthesized a series of quinolinium-modified cyclosporine derivatives targeted to the mitochondrial cyclophilin D protein. Modification of the cation to enable greater delocalization was confirmed by x-ray crystallography of the cations. Critically, greater delocalization improved brain concentrations. Assessment of the compounds in preclinical assays and for pharmacokinetics identified a molecule JP1-138 with at least 20 times the brain levels of a non-delocalized compound or those reported for cyclosporine. Levels were maintained over 24 hours together with low hERG potential. The paradigm outlined here could have widespread utility in the treatment of CNS diseases.

TRLS-08. ROVER: A PHASE 1/2 TRIAL IN PROGRESS OF AVAPRITINIB IN PEDIATRIC PATIENTS WITH SOLID TUMORS DEPENDENT ON KIT OR PDGFRA SIGNALING

Abstract BACKGROUND Advanced pediatric solid tumors, including central nervous system (CNS) tumors with PDGFRA and/or KIT mutations/amplifications are aggressive diseases with limited treatment options. KIT alterations occur in germ cell tumors and high-grade glioma (HGG); platelet-derived growth factor receptor alpha (PDGFRA) alterations are common in sarcoma and HGG. No KIT-/PDGFRA-targeted therapies are currently approved for pediatric patients. The selective KIT and PDGFRA inhibitor avapritinib has demonstrated potent activity against KIT activation-loop (exon 17) and juxtamembrane (exon 11) mutants (IC50<2 nM), and PDGFRA activation-loop (D842V) mutants (half-maximal inhibitory concentration [IC50]=0.24 nM). Cellular IC50 of wild-type PDGFRA was 95 nM. CNS penetration in preclinical models (steady-state brain-to-plasma ratios, 0.74–1.00) indicates potential for CNS antitumor activity. Avapritinib is approved in the USA and Europe to treat adults with indolent systemic mastocytosis, in the USA for adults with advanced systemic mastocytosis (AdvSM), and in Europe for adults with AdvSM after ≥1 prior systemic therapy. Avapritinib is also approved to treat adults with unresectable/metastatic gastrointestinal stromal tumors harboring PDGFRA exon 18 mutations (including D842V) in the USA and PDGFRA D842V mutations in Europe. METHODS ROVER, a 2-part phase 1/2, multicenter, open-label study (NCT04773782), is investigating avapritinib (once daily, administered in continuous 28-day cycles) in pediatric patients aged 2 to <18 years with relapsed/refractory solid tumors that harbor PDGFRA and/or KIT mutations/amplifications or patients with diffuse midline glioma H3K27-altered (DMG-H3K27a). Objectives include safety, efficacy, and pharmacokinetics. Part 1 will enroll ≥12 patients; primary endpoint is to determine the recommended Part 2 dose (RP2D). Part 2 will enroll ≥25 patients at the RP2D; primary endpoint is objective response rate per RECIST v1.1 for solid tumors and Response Assessment in Neuro-Oncology for CNS tumors. Study enrollment is planned at 26 sites in 9 countries, including North America, Europe, and Asia/Pacific.

Revisiting intrathecal thiotepa: Efficacy and safety in secondary CNS malignancies.

Treating metastatic malignancies to the central nervous system (CNS) is challenging because many drugs cannot cross the blood-brain-barrier (BBB). Direct intrathecal (IT) drug administration into the cerebrospinal fluid (CSF) is a strategy to overcome this problem. Thiotepa has effective CNS penetration but its popularity has waned over the last two decades due to concerns about its efficacy and potential systemic toxicity. This review evaluates the available evidence for the use of IT thiotepa in hematologic malignancies and non-CNS solid tumors with leptomeningeal disease metastases (LMD). Our search shows that IT thiotepa is a reasonable alternative in hematologic malignancies and LMD due to solid organ malignancies. This suggests a potential role of IT thiotepa in second-or third-line treatment or a substitute role in cases of drug-shortages and adverse effects with other agents. Future research should focus on rigorous comparative trials to establish its definitive role in the evolving landscape of CNS-directed chemotherapy.

Radiosurgery to 5 or more newly diagnosed brain metastases in the systemic therapy era.

2026 Background: Stereotactic radiosurgery (SRS) is an ablative modality for focal treatment of brain metastases (BM) and is standard of care for limited BM. Suitability for SRS has historically been linked to number of BM, with up to 4 BM considered amenable to SRS. JLGK0901 revealed no difference in overall survival (OS) and similar rates of adverse events for patients with 5-10 vs. 2-4 BM. Evidence supporting for SRS for >10 BM is limited. As systemic treatments have evolved to include agents with improved central nervous system (CNS) efficacy and OS, the role of SRS warrants re-evaluation. Methods: We retrospectively reviewed patients from a single institution with ≥5 BM treated with SRS with no prior history of brain radiation 2015-2022 on an IRB-approved protocol. Clinical history, including sex, histology, Karnofsky performance status (KPS), extracranial disease status and systemic regimen used before and after diagnosis of BM, was reviewed. Systemic regimens were categorized based on potential for CNS efficacy as 1) none: no evidence, 2) weak: single agent immunotherapy or known but limited data on CNS efficacy, or 3) strong: multiple agents with known CNS efficacy, single agents with strong CNS efficacy. Kaplan-Meier method was used to estimate survival with log-rank test used to evaluate differences in survival curves. Cox proportional hazards modeling was used to evaluate differences in CNS progression-free survival (CNS-PFS) and OS. Results: 558 patients (48% female) who received SRS to ≥5 BM (range 5-23) were identified. Primary histologies included: 36% non-small cell lung cancer; 22% melanoma; 14% breast; 7% renal; 5% gastrointestinal; 15% other. Median OS was 11.0 months and did not differ between patients with 5-9 (n=441) vs ≥10 BM (n=117) (median OS 11.1 vs. 10.0 months; p=0.53). Median CNS-PFS was 6.6 months and did not differ between 5-9 vs ≥ 10 BM (median CNS-PFS 6.4 vs. 7.7 p=0.86). On univariate analysis, high KPS (HR 0.96; p<0.001) was associated with improved OS. Histology ( p=0.14), BM number ( p=0.53); average BM volume ( p=0.48), and systemic disease status ( p=0.17) were not associated with OS. Change of systemic therapy at time of SRS was associated with improved OS (HR 0.58; p<0.001) and CNS-PFS (HR 0.63; p<0.001). Amongst patients with systemic therapy change, regimens with increased CNS efficacy compared to prior therapy were associated with improved OS (HR 0.59; p<0.001) and CNS-PFS (HR 0.65; p=0.002). Conclusions: In this large, retrospective analysis of patients with ≥ 5 previously untreated BM treated with SRS, we found no association between BM number and CNS-PFS or OS. Change in systemic therapy, particularly to agents with CNS efficacy, was associated with improved outcomes. While limited by biases inherent to retrospective analyses, these results suggest patients with larger number of BM (≥10) are appropriate for SRS, especially when changing to systemic therapy with CNS penetrance.

Targeted Therapies for EGFR Exon 20 Insertion Mutation in Non-Small-Cell Lung Cancer.

Non-small-cell lung cancer (NSCLC) frequently harbors mutations in the epidermal growth factor receptor (EGFR), with exon 20 insertions comprising 1-10% of these mutations. EGFR exon 20 insertions are less responsive to conventional tyrosine kinase inhibitors (TKIs), leading to the development of targeted agents. This review explores key therapeutic agents, such as Amivantamab, Mobocertinib, Poziotinib, Zipalertinib, and Sunvozertinib, which have shown promise in treating NSCLC with EGFR exon 20 insertions. Amivantamab, a bispecific antibody-targeting EGFR and c-MET, demonstrates significant efficacy, particularly when combined with chemotherapy. Mobocertinib, a TKI, selectively targets EGFR exon 20 mutations but faces limitations in efficacy. Poziotinib, another oral TKI, shows mixed results due to mutation-specific responses. Zipalertinib and Sunvozertinib have emerged as potent TKIs with promising clinical data. Despite these advances, challenges in overcoming resistance mutations and improving central nervous system penetration remain. Future research should focus on optimizing first-line combination therapies and enhancing diagnostic strategies for comprehensive mutation profiling.

Comprehensive Review on the Virulence Factors and Therapeutic Strategies with the Aid of Artificial Intelligence against Mucormycosis.

Mucormycosis, a rare but deadly fungal infection, was an epidemic during the COVID-19 pandemic. The rise in cases (COVID-19-associated mucormycosis, CAM) is attributed to excessive steroid and antibiotic use, poor hospital hygiene, and crowded settings. Major contributing factors include diabetes and weakened immune systems. The main manifesting forms of CAM─cutaneous, pulmonary, and the deadliest, rhinocerebral─and disseminated infections elevated mortality rates to 85%. Recent focus lies on small-molecule inhibitors due to their advantages over standard treatments like surgery and liposomal amphotericin B (which carry several long-term adverse effects), offering potential central nervous system penetration, diverse targets, and simpler dosing owing to their small size, rendering the ability to traverse the blood-brain barrier via passive diffusion facilitated by the phospholipid membrane. Adaptation and versatility in mucormycosis are facilitated by a multitude of virulence factors, enabling the pathogen to dynamically respond to various environmental stressors. A comprehensive understanding of these virulence mechanisms is imperative for devising effective therapeutic interventions against this highly opportunistic pathogen that thrives in immunocompromised individuals through its angio-invasive nature. Hence, this Review delineates the principal virulence factors of mucormycosis, the mechanisms it employs to persist in challenging host environments, and the current progress in developing small-molecule inhibitors against them.

Abstract 6472: Response to PARP inhibitors in patients with breast cancer metastatic to the central nervous system

Abstract Background: Central nervous system (CNS) metastasis from breast cancer can be challenging to treat due to the limited blood brain barrier penetration of many systemic therapies. PARP inhibitors (PARPi) block single-strand DNA break repairs and have activity in cancers with homologous recombination repair deficiency; they are FDA approved for patients with metastatic HER2 negative breast cancer with germline BRCA1/2 mutations. While preclinical studies suggest that PARPi have CNS penetration, clinical data is limited. The goal of our study is to describe the clinical benefit of PARPi in patients with breast cancer CNS metastasis. Methods: This retrospective case series was conducted at three academic cancer centers (Johns Hopkins, Dana-Farber, and Duke) and included patients with the following criteria: (1) age≥18 years with a breast cancer diagnosis (any subtype); (2) diagnosis of parenchymal brain metastasis or leptomeningeal disease (LMD); and (3) received PARPi (olaparib, talazoparib) for CNS metastasis. Clinical and pathologic information were analyzed with descriptive statistics (median, range) and Kruskal-Wallis rank sum tests. Survival analysis was performed using Kaplan-Meier curves with log-rank p-values. Results: Although this analysis includes one center’s experience, we will present a combined dataset (N = 45) at the main conference. 11 patients were identified at Johns Hopkins. 4 (36.4%) were Black and 6 (54.5%) were White; 6 (54.5%) had ER+HER2- disease and 5 (45.5%) had TNBC at time of brain metastasis; 5 (45.5%) had BRCA1 mutations, 5 (45.5%) had a BRCA2 mutations, and 1 patient (9%) had a BARD1 mutation; 7 (63.6%) had brain metastasis and 4 (36.4%) had LMD. Median lines of therapy prior to PARPi was 6 [1 - 11]; 8 patients (72.7%) had previous CNS radiation (5 SRS and 3 WBRT) and 3 (27.3%) had previous CNS surgery. On average, patients remained on PARPi for 5 months [0.5 - 66], and overall survival (OS) time from PARPi to death was 16 months [2 - 66]. Time on PARPi was 5 months [2 - 66] for patients with brain metastasis and 3 months [0.5 - 10] for those with LMD (p=0.22). Duration of PARPi and OS did not differ significantly between ER+HER2- and TNBC (p=0.74 and 0.69, respectively), BRCA 1 and 2 (p=0.78 and 0.72, respectively), or brain and LMD metastasis (p=0.22 and 0.91, respectively). Black patients had significantly shorter PARPi duration and survival than White patients (PARPi 2 vs. 8 months, p=0.028 and OS 4 vs 18 months, p=0.028). Prior CNS radiation was significantly associated with longer PARPi duration and survival (PARPi 5 vs 1 month, p=0.02 and OS 17 vs. 3 months, p=0.032). Prior CNS surgery was significantly associated with longer PARPi duration, but not overall survival (PARPi 18 vs 3 months, p=0.05 and OS 28 vs. 7 months, p=0.14). Conclusions: PARPi are associated with significant clinical benefit in patients with breast cancer CNS metastasis. Larger data series will help confirm these observations. Citation Format: Seoho Lee, Rani Bansal, Melissa E. Hughes, Amanda E. Van Swearingen, Heather N. Moore, David O. Kamson, Solmaz Sahebjam, Greg Kirkner, Anna Gorfinkel, Sarah Sammons, Nancy U. Lin, Carey Anders, Cesar A. Santa-Maria. Response to PARP inhibitors in patients with breast cancer metastatic to the central nervous system [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6472.

Experimental and Computational Methods to Assess Central Nervous System Penetration of Small Molecules.

In CNS drug discovery, the estimation of brain exposure to lead compounds is critical for their optimization. Compounds need to cross the blood-brain barrier (BBB) to reach the pharmacological targets in the CNS. The BBB is a complex system involving passive and active mechanisms of transport and efflux transporters such as P-glycoproteins (P-gp) and breast cancer resistance protein (BCRP), which play an essential role in CNS penetration of small molecules. Several in vivo, in vitro, and in silico methods are available to estimate human brain penetration. Preclinical species are used as in vivo models to understand unbound brain exposure by deriving the Kp,uu parameter and the brain/plasma ratio of exposure corrected with the plasma and brain free fraction. The MDCK-mdr1 (Madin Darby canine kidney cells transfected with the MDR1 gene encoding for the human P-gp) assay is the commonly used in vitro assay to estimate compound permeability and human efflux. The in silico methods to predict brain exposure, such as CNS MPO, CNS BBB scores, and various machine learning models, help save costs and speed up compound discovery and optimization at all stages. These methods enable the screening of virtual compounds, building of a CNS penetrable compounds library, and optimization of lead molecules for CNS penetration. Therefore, it is crucial to understand the reliability and ability of these methods to predict CNS penetration. We review the in silico, in vitro, and in vivo data and their correlation with each other, as well as assess published experimental and computational approaches to predict the BBB penetrability of compounds.

Ceftaroline for Central Nervous System Infections: Case Report of a Young Infant, and Scoping Review.

Managing health care acquired and device-associated intracranial infections in young children can be challenging given adverse antibiotic side effects and difficulties in achieving adequate central nervous system (CNS) antibiotic concentrations. Ceftaroline is a cephalosporin with a favorable safety profile and activity against methicillin-resistant Staphylococci and several Gram-negative organisms. Published data on the use of ceftaroline for CNS infections in children and adults are limited. We describe a 2-month-old infant with ventriculo-subgaleal shunt-associated methicillin-resistant Staphylococcus epidermidis ventriculitis, which was successfully treated with ceftaroline, in addition to vancomycin and rifampin. We conducted a scoping review of English-language literature retrieved from PubMed, EMBASE and Web of Science that assessed the use of ceftaroline for CNS infections. We identified 22 articles for inclusion in our review, which described 92 unique patients, of whom 2 were <21 years old. Ceftaroline was commonly used in conjunction with other antibiotics to treat infections caused by Staphylococcus aureus , coagulase-negative Staphylococci and Streptococcus pneumoniae . Most case reports described clinical success with ceftaroline, though small case series and cohort studies yielded mixed efficacy assessments. Adverse effects attributed to ceftaroline were rare and included reversible myelosuppression, eosinophilia, hepatotoxicity and nephrotoxicity. Pharmacokinetic/pharmacodynamic studies suggested similar CNS penetration through inflamed meninges as other beta lactam antibiotics. We identified a growing body of published evidence supporting the use of ceftaroline in combination with other agents for the treatment of CNS infections. In absence of clinical trials, additional real-world data are needed to define the efficacy and safety of ceftaroline for children and adults with CNS infections.

Phase 1 Healthy Volunteer Study of AL01211, an Oral, Non-brain Penetrant Glucosylceramide Synthase Inhibitor, to Treat Fabry Disease and Type 1 Gaucher Disease.

Glycosphingolipid (GSL) storage diseases are caused by deficiencies in the enzymes that metabolize different GSLs in the lysosome. Glucosylceramide synthase (GCS) inhibitors reduce GSL production and have potential to treat multiple GSL storage diseases. AL01211 is a potent, oral GCS inhibitor being developed for the treatment of Type 1 Gaucher disease and Fabry disease. AL01211 has minimal central nervous system penetration, allowing for treatment of peripheral organs without risking CNS-associated adverse effects. AL01211 was evaluated in a Phase 1 healthy volunteer study with single ascending dose (SAD) and multiple ascending dose (MAD) arms, to determine safety, pharmacokinetics including food effect, and pharmacodynamic effects on associated GSLs. In the SAD arm, AL01211 showed a Tmaxof approximately 3.5 hours, mean clearance (CL/F) of 130.1 L/h, and t1/2of 39.3 hours. Consuming a high-fat meal prior to dose administration reduced exposures 3.5-5.5-fold, indicating a food effect. In the MAD arm, AL01211 had an approximately 2-fold accumulation, reaching steady-state levels by 10 days. Increasing exposure inversely correlated with a decrease in GSL with plasma glucosylceramide and globotriacylceramide reduction from baseline levels, reaching 78% and 52% by day 14, respectively. AL01211 was generally well-tolerated with no AL01211 associated serious adverse events, thus supporting its further clinical development.

Durable response to first-line treatment with AZD3759 (zorifertinib) in a patient with epithelial growth factor receptor mutated non-small cell lung cancer and untreated multiple brain metastasis

Central nervous system (CNS) metastases, including brain and leptomeningeal metastasis, are associated with poor prognosis in epidermal growth factor receptor (&lt;i&gt;EGFR&lt;/i&gt;)-mutated non-small cell lung cancer (NSCLC) patients. CNS metastasis occurs in more than 50% of &lt;i&gt;EGFR&lt;/i&gt;-mutated NSCLC cases during the treatment course. The treatment options for CNS metastases in these patients are limited, and there have been ongoing efforts to develop targeted agents with enhanced CNS penetration. AZD3759 (zorifertinib) is a novel &lt;i&gt;EGFR&lt;/i&gt; tyrosine kinase inhibitor with a high capability of CNS penetration and proven efficacy with tolerable safety profiles. In this report, we describe a case of a patient with &lt;i&gt;EGFR&lt;/i&gt;-mutant NSCLC that was initially diagnosed with multiple brain metastasis who demonstrated prolonged response of both intra- and extracranial lesions over 7 years with AZD3759 as first-line treatment.

Series of (([1,1'-Biphenyl]-2-yl)methyl)sulfinylalkyl Alicyclic Amines as Novel and High Affinity Atypical Dopamine Transporter Inhibitors with Reduced hERG Activity.

Currently, there are no FDA-approved medications for the treatment of psychostimulant use disorders (PSUD). We have previously discovered "atypical" dopamine transporter (DAT) inhibitors that do not display psychostimulant-like behaviors and may be useful as medications to treat PSUD. Lead candidates (e.g., JJC8-091, 1) have shown promising in vivo profiles in rodents; however, reducing hERG (human ether-à-go-go-related gene) activity, a predictor of cardiotoxicity, has remained a challenge. Herein, a series of 30 (([1,1'-biphenyl]-2-yl)methyl)sulfinylalkyl alicyclic amines was synthesized and evaluated for DAT and serotonin transporter (SERT) binding affinities. A subset of analogues was tested for hERG activity, and the IC50 values were compared to those predicted by our hERG QSAR models, which showed robust predictive power. Multiparameter optimization scores (MPO > 3) indicated central nervous system (CNS) penetrability. Finally, comparison of affinities in human DAT and its Y156F and Y335A mutants suggested that several compounds prefer an inward facing conformation indicating an atypical DAT inhibitor profile.

Palliative radiotherapy for leptomeningeal metastases after photon-based intensity-modulated radiotherapy in a nasopharyngeal cancer patient.

Leptomeningeal metastasis is a rare in nasopharyngeal carcinoma, affecting less than 5% of patients with a poor prognosis. The aim of this case report was to present management of palliative radiotherapy in leptomeningeal metastasis of nasopharyngeal carcinoma patient. A 33-year-old female presented with nasopharyngeal carcinoma with stage III, T3N3M0, WHO type III. The patient has received chemoradiation with photon-based intensity-modulated radiotherapy (IMRT) technique at the dose of 70 Gy in 33 fractions and showed a satisfactory outcome in 12 months follow-up. Later, at 18 months after chemoradiation completion, the patient complained of worsening bilateral sciatic pain, particularly during coughing, with slight limitations in bilateral hip flexion observed during straight leg raises. The whole spine contrast-enhanced magnetic resonance imaging (MRI) examination showed nodular enhancement of leptomeningeal thickening at the T4 level of the spinal cord lower than S3. Palliative radiation therapy utilized a three-dimensional conformal radiation therapy (3D-CRT) technique producing 35 Gy in 14 fractions placed in a field spanning the T4-S3 vertebral bodies. Methotrexate was administered intravenously every two weeks for three cycles to ensure central nervous system penetration. After four months of follow-up, no evidence of disease was found at the primary site and metastatic areas on subsequent physical examination or imaging with MRI and there was satisfactory improvement in neurologic symptoms. In conclusion, leptomeningeal metastases with primary nasopharyngeal carcinoma are rare and typically cause neurological impairments in patients. Hematogenous or cerebrospinal fluid-mediated spread of the cancer is considered the most likely pathway for leptomeningeal dissemination. Strategic modalities, such as radiotherapy with chemotherapy, may improve outcomes in symptoms and quality of life.

Abstract B157: Preclinical evaluation of the blood-brain barrier permeability and intracranial efficacy of the next-generation RET inhibitor Vepafestinib

Abstract Background. Drug resistance and central nervous system (CNS) metastasis often hampers response to precision therapy for RET-rearranged solid tumors. Vepafestinib (Vepa) is a clinical-stage, potent and selective RET tyrosine-kinase inhibitor (TKI) with proven activity against on-target resistance mutations that arise post first-generation RET TKI. Here, we utilized an array of structural and pharmacokinetic methods to determine blood-brain barrier (BBB) permeability of vepa compared with other RET TKIs. Furthermore, we correlate BBB penetrability of RET inhibitors with in vivo efficacy in preclinical models of RET-rearranged intracranial solid tumors. Methods. RET inhibitors were generated by rational chemical design to identify agents which penetrate BBB more effectively than currently approved RET TKIs, and with reduced efflux transporter susceptibility. Transcellular transport assays were conducted in LLC-PK1 and MDCK II cells expressing P-gp and BCRP, respectively. Brain penetrability was assessed by total (Kp) and unbound (Kp,uu) brain:plasma concentration ratios in male Balb/c mice and microdialysis studies in freely-moving male Wistar rats. Models of CNS metastasis were generated by implanting cells labelled with luciferase into the cerebellum of mice. Studies were conducted in comparison with selpercatinib (Selp), pralsetinib (Pral) and TPX-0046. Results. Assessment of Kp and Kp,uu parameters of analogs revealed an excellent structure-activity relationship where modification at the 6-position of the pyrrolopyrimidine core resulted in improved BBB penetrability. The analog with the most favorable physiochemical and biological properties was Vepa. Vepa showed poor susceptibility to P-gp and BCRP-mediated efflux and better CNS penetrability (Kp,uu: 1.3) and retention than Sel, Pral and TPX-0046. The ratio of the observed concentrations of Vepa in microdialysates from the prefrontal cortex, cerebrospinal fluid (CSF) and plasma free fraction was approximately 1:1:1; these ratios were maintained from 2h to 6.5h after Vepaadministration (up to 8h for CSF). Importantly, Vepa was more effective than Selp at causing regression of intracranial xenograft tumors of RET fusion-driven malignancies (lung adenocarcinoma and sarcoma), thus extending survival of tumor-bearing animals. Common first-generation RET TKI resistance mutations at the solvent front (G810A/C/S/R), gatekeeper (V804L/M), hinge (Y806C) and roof (L730Q/R) regions remained sensitive to Vepa. Vepa was more selective than Selp, Pral and TPX-0046, inhibiting only RET when profiled against a panel of 256 kinases. In contrast, Selp, Pral and TPX-0045 also inhibited VEGFR2, and 4, 11 and 39 additional kinases, respectively. Conclusions. Vepafestinib is a structurally distinct and specific RET inhibitor, with superior brain penetration and retention kinetics. It is more effective than selpercatinib in controlling CNS disease. Vepafestinib is currently undergoing phase 1 and 2 clinical trial for patients with advanced solid tumors with RET alterations (margaRET, NCT04683250). Citation Format: Igor Odintsov, Kentaro Wakayama, Tom Zhang, Satoru Iguchi, Masanori Kato, Allan JW Lui, Inna Khodos, Morana Vojnic, Claudio Giuliano, Annalisa Bonifacio, Monika A Davare, Elisa de Stanchina, Emanuela Lovati, Marc Ladanyi, Isao Miyazaki, Romel Somwar. Preclinical evaluation of the blood-brain barrier permeability and intracranial efficacy of the next-generation RET inhibitor Vepafestinib [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr B157.