Afatinib and radiotherapy, with or without temozolomide, in patients with newly diagnosed glioblastoma: results of a phase I trial

Folic Acid Functionalized AQ4N/Gd@PDA Nanoplatform with Real-Time Monitoring of Hypoxia Relief and Enhanced Synergistic Chemo/Photothermal Therapy in Glioma

Purpose

Hypoxia is often associated with glioma chemoresistance, and alleviating hypoxia is also crucial for improving treatment efficacy. However, although there are already some methods that can improve efficacy by alleviating hypoxia, real-time monitoring that can truly achieve hypoxia relief and efficacy feedback still needs to be explored.

Methods

AQ4N/Gd@PDA-FA nanoparticles (AGPF NPs) were synthesized using a one-pot method and were characterized. The effects of AGPF NPs on cell viability, cellular uptake, and apoptosis were investigated using the U87 cell line. Moreover, the effectiveness of AGPF NPs in alleviating hypoxia was explored in tumor-bearing mice through photoacoustic imaging. In addition, the diagnosis and treatment effect of AGPF NPs were evaluated by magnetic resonance imaging (MRI) and bioluminescent imaging (BLI) on orthotopic glioma mice respectively.

Results

In vitro experiments showed that AGPF NPs had good dispersion, stability, and controlled release. AGPF NPs were internalized by cells through endocytosis, and could significantly reduce the survival rate of U87 cells and increase apoptosis under irradiation. In addition, we monitored blood oxygen saturation at the tumor site in real-time through photoacoustic imaging (PAI), and the results showed that synergistic mild-photothermal therapy/chemotherapy effectively alleviated tumor hypoxia. Finally, in vivo anti-tumor experiments have shown that synergistic therapy can effectively alleviate hypoxia and inhibit the growth of orthotopic gliomas.

Conclusion

This work not only provides an effective means for real-time monitoring of the dynamic feedback between tumor hypoxia relief and therapeutic efficacy, but also offers a potential approach for the clinical treatment of gliomas.

Improving the efficacy of anti-EGFR drugs in GBM: Where we are going?

The therapies targeting mutations of driver genes in cancer have advanced into clinical trials for a variety of tumors. In glioblastoma (GBM), epidermal growth factor receptor (EGFR) is the most commonly mutated oncogene, and targeting EGFR has been widely investigated as a promising direction. However, the results of EGFR pathway inhibitors have not been satisfactory. Limited blood-brain barrier (BBB) permeability, drug resistance, and pathway compensation mechanisms contribute to the failure of anti-EGFR therapies. This review summarizes recent research advances in EGFR-targeted therapy for GBM and provides insight into the reasons for the unsatisfactory results of EGFR-targeted therapy. By combining the results of preclinical studies with those of clinical trials, we discuss that improved drug penetration across the BBB, the use of multi-target combinations, and the development of peptidomimetic drugs under the premise of precision medicine may be promising strategies to overcome drug resistance in GBM.

Afatinib in paediatric patients with recurrent/refractory ErbB-dysregulated tumours: Results of a phase I/expansion trial

AIM

This phase I/expansion study assessed the safety, pharmacokinetics and preliminary antitumor activity of afatinib in paediatric patients with cancer.

METHODS

The dose-finding part enroled patients (2-<18 years) with recurrent/refractory tumours. Patients received 18 or 23 mg/m2/d afatinib orally (tablet or solution) in 28-d cycles. In the maximum tolerated dose (MTD) expansion, eligible patients (1-<18 years) had tumours fulfilling ≥2 of the following criteria in the pre-screening: EGFR amplification; HER2 amplification; EGFR membrane staining (H-score>150); HER2 membrane staining (H-score>0). The primary end-points were dose-limiting toxicities (DLTs), afatinib exposure, and objective response.

RESULTS

Of 564 patients pre-screened, 536 patients had biomarker data and 63 (12%) fulfilled ≥2 EGFR/HER2 criteria required for inclusion in the expansion part. A total of 56 patients were treated (17 in the dose-finding and 39 in the expansion part). DLTs were observed in one of six MTD-evaluable patients receiving 18 mg/m²/d and in two of five MTD-evaluable patients receiving 23 mg/m²/d; 18 mg/m²/d was defined as the MTD. There were no new safety signals. Pharmacokinetics confirmed exposure consistent with the approved dose in adults. One partial response (-81% per Response Assessment in Neuro-Oncology) was observed in a patient with a glioneuronal tumour harbouring a CLIP2::EGFR fusion; unconfirmed partial responses were observed in two patients. In total, 25% of patients experienced objective response or stable disease (95% confidence interval: 14-38).

CONCLUSION

Targetable EGFR/HER2 drivers are rare in paediatric cancers. Treatment with afatinib led to a durable response (>3 years) in one patient with a glioneuronal tumour with CLIP2::EGFR fusion.

Hit discovery of novel 2-phenyl-substituted 4-amino-6,7-dihydro-5H-cyclopenta[d]pyrimidines as potential anti-glioblastoma therapeutics: Design, synthesis, biological evaluation, and computational screening

Glioblastoma multiforme (GBM) is a highly-aggressive, dreadful disease with poor prognosis and disappointing clinical success. There is an unmet medical need of molecularly-targeted therapeutics for GBM treatment. In the present work, a series of novel 2-phenyl-substituted 4-amino-6,7-dihydro-5H-cyclopenta[d]pyrimidines was designed, synthesized, purified, characterized, and evaluated for cytotoxicity against glioblastoma cell line U87-MG. The design process (virtual library enumeration around the core, physicochemical and molecular property prediction/calculation of the designs, filtering the undesirable ones, and the diversity analyses of the lead-like designs), was carefully curated so as to obtain a set of structurally-diverse, novel molecules (total 20), with a particular focus on the relatively unexplored core structure, 6,7-dihydro-5H-cyclopenta[d]pyrimidine. The preliminary screening was done using MTT assay at 10 and 100 μM concentrations of the title compounds F₁ -F₂₀ and positive control cisplatin, which yielded six hits (% inhibition at 10 μM: ~50%)-F₂ , F₃ , F₅ , F₇ , F₁₅ , and F₂₀ , which were taken up for IC₅₀ determination. The top hits F₂ and F₇ (IC₅₀  < 10 μM) were further used for computational studies such as target prediction, followed by their molecular docking in the binding sites of the top-3 predicted targets (epidermal growth factor receptor kinase domain, cyclin-dependent kinase 2 [CDK2]) /cyclin E, and anaplastic lymphoma kinase [ALK]). The docking pose analyses revealed interesting trends. The relatively planar core structure, presence of favorable hinge-binding substructures, basic groups, all added up, and culminated in appreciable cytotoxicity against GBM cell line.

Most recent update of preclinical and clinical data on radioresistance and radiosensitivity of high-grade gliomas-a radiation oncologist's perspective

PURPOSE

This review article discusses the studies concerning advances in radiotherapy of high-grade gliomas published in the second half of 2021.

METHODS

A literature search was performed in PubMed using the terms ("gliom* and radio*") and time limits 1 July 2021-31 December 2021. The articles were then manually selected for relevance to the analyzed topics.

RESULTS

Considerable progress has been made in the preclinical field on the mechanisms of radioresistance and radiosensitization of high-grade gliomas (HGG). However, fewer early-phase (I/II) clinical trials have been performed and, of the latter, even fewer have produced results that justify moving to phase III. In the 6‑month period under consideration, no studies were published that would lead to a change in clinical practice and the overall survival (OS) of patients remained similar to that of 2005, the year in which it increased significantly for the last time thanks to introduction of the alkylating agent temozolomide.

CONCLUSION

After 17 years of stalemate in improving the OS of patients with HGG, an in-depth analysis of the causes should be carried out in order to identify whether the research efforts conducted so far, including in the radiotherapeutic field, have been the most effective or require improvement. In our opinion, in addition to the therapeutic difficulties related to the biology of HGG tumors (e.g., high infiltrating capacity, multiple resistance mechanisms, blood-brain barrier), some public research policy choices may also play a role, especially in consideration of the limited interest of the pharmaceutical industry in the field of rare cancers.

Receptor tyrosine kinase (RTK) targeting in pediatric high-grade glioma and diffuse midline glioma: Pre-clinical models and precision medicine

Pediatric high-grade glioma (pHGG), including both diffuse midline glioma (DMG) and non-midline tumors, continues to be one of the deadliest oncologic diagnoses (both henceforth referred to as “pHGG”). Targeted therapy options aimed at key oncogenic receptor tyrosine kinase (RTK) drivers using small-molecule RTK inhibitors has been extensively studied, but the absence of proper in vivo modeling that recapitulate pHGG biology has historically been a research challenge. Thankfully, there have been many recent advances in animal modeling, including Cre-inducible transgenic models, as well as intra-uterine electroporation (IUE) models, which closely recapitulate the salient features of human pHGG tumors. Over 20% of pHGG have been found in sequencing studies to have alterations in platelet derived growth factor-alpha (PDGFRA), making growth factor modeling and inhibition via targeted tyrosine kinases a rich vein of interest. With commonly found alterations in other growth factors, including FGFR, EGFR, VEGFR as well as RET, MET, and ALK, it is necessary to model those receptors, as well. Here we review the recent advances in murine modeling and precision targeting of the most important RTKs in their clinical context. We additionally provide a review of current work in the field with several small molecule RTK inhibitors used in pre-clinical or clinical settings for treatment of pHGG.

Galvanotactic Migration of Glioblastoma and Brain Metastases Cells

Galvanotaxis, the migration along direct current electrical fields, may contribute to the invasion of brain cancer cells in the tumor-surrounding tissue. We hypothesized that pharmacological perturbation of the epidermal growth factor (EGF) receptor and downstream phosphatidylinositol 3-kinase (PI3K)/AKT pathway prevent galvanotactic migration. In our study, patient-derived glioblastoma and brain metastases cells were exposed to direct current electrical field conditions. Velocity and direction of migration were estimated. To determine the effects of EGF receptor antagonist afatinib and AKT inhibitor capivasertib, assays of cell proliferation, apoptosis and immunoblot analyses were performed. Both inhibitors attenuated cell proliferation in a dose-dependent manner and induced apoptosis. We found that most of the glioblastoma cells migrated preferentially in an anodal direction, while brain metastases cells were unaffected by direct current stimulations. Afatinib presented only a mild attenuation of galvanotaxis. In contrast, capivasertib abolished the migration of glioblastoma cells without genetic alterations in the PI3K/AKT pathway, but not in cells harboring PTEN mutation. In these cells, an increase in the activation of ERK1/2 may in part substitute the inhibition of the AKT pathway. Overall, our data demonstrate that glioblastoma cells migrate in the electrical field and the PI3K/AKT pathway was found to be highly involved in galvanotaxis.

Genomic Analysis of Tumors from Patients with Glioblastoma with Long-Term Response to Afatinib

Glioblastoma is an aggressive form of central nervous system tumor. Recurrence rates following primary therapy are high, and few second-line treatment options provide durable clinical benefit. Aberrations of the epidermal growth factor receptor (EGFR) gene are observed in up to 57% of glioblastoma cases and EGFR overexpression has been identified in approximately 60% of primary glioblastomas. In preclinical studies, afatinib, a second-generation ErbB blocker, inhibited cell proliferation in cells harboring mutations commonly found in glioblastoma. In two previous Phase I/II studies of afatinib plus temozolomide in patients with glioblastoma, limited efficacy was observed; however, there was notable benefit in patients with the EGFR variant III (EGFRvIII) mutation, EGFR amplification, and those with loss of phosphatase and tensin homolog (PTEN). This case series report details treatment histories of three long-term responders from these trials. Next-generation sequencing of tumor samples identified alterations in a number of cancer-related genes, including mutations in, and amplification of, EGFR. Tumor samples from all three patients shared favorable prognostic factors, eg O⁶-methylguanine-DNA methyl-transferase (MGMT) gene promoter methylation; however, negative prognostic factors were also observed, suggesting that these shared genetic features did not completely account for the favorable responses. The genetic profile of the tumor from Patient 1 showed clear differences from the other two tumors: lack of involvement of EGFR aberrations but with a mutation occurring in PTPN11. Preclinical studies showed that single-agent afatinib and temozolomide both separately inhibit the growth of tumors with a C-terminal EGFR truncation, thus providing further rationale for combining these two agents in the treatment of glioblastomas harboring EGFR aberrations. These findings suggest that afatinib may provide treatment benefit in patients with glioblastomas that harbor ErbB family aberrations and, potentially, other genetic aberrations. Further studies are needed to establish which patients with newly diagnosed/recurrent glioblastomas may potentially benefit from treatment with afatinib.

Therapeutic strtegies of glioblastoma (GBM): The current advances in the molecular targets and bioactive small molecule compounds

Glioblastoma (GBM) is the most common aggressive malignant tumor in brain neuroepithelial tumors and remains incurable. A variety of treatment options are currently being explored to improve patient survival, including small molecule inhibitors, viral therapies, cancer vaccines, and monoclonal antibodies. Among them, the unique advantages of small molecule inhibitors have made them a focus of attention in the drug discovery of glioblastoma. Currently, the most used chemotherapeutic agents are small molecule inhibitors that target key dysregulated signaling pathways in glioblastoma, including receptor tyrosine kinase, PI3K/AKT/mTOR pathway, DNA damage response, TP53 and cell cycle inhibitors. This review analyzes the therapeutic benefit and clinical development of novel small molecule inhibitors discovered as promising anti-glioblastoma agents by the related targets of these major pathways. Meanwhile, the recent advances in temozolomide resistance and drug combination are also reviewed. In the last part, due to the constant clinical failure of targeted therapies, this paper reviewed the research progress of other therapeutic methods for glioblastoma, to provide patients and readers with a more comprehensive understanding of the treatment landscape of glioblastoma.