The response and survival of children with recurrent diffuse intrinsic pontine glioma based on phase II study of antineoplastons A10 and AS2-1 in patients with brainstem glioma

Pediatric diffuse midline glioma: Understanding the mechanisms and assessing the next generation of personalized therapeutics

Diffuse midline glioma (DMG) is a pediatric cancer that originates in the midline structures of the brain. Prognosis of DMG patients remains poor due to the infiltrative nature of these tumors and the protection they receive from systemically delivered therapeutics via an intact blood-brain barrier (BBB), making treatment difficult. While the cell of origin remains disputed, it is believed to reside in the ventral pons. Recent research has pointed toward epigenetic dysregulation inducing an OPC-like transcriptomic signature in DMG cells. This epigenetic dysregulation is typically caused by a mutation (K27M) in one of two histone genes-H3F3A or HIST1H3B -and can lead to a differentiation block that increases these cells oncogenic potential. Standard treatment with radiation is not sufficient at overcoming the aggressivity of this cancer and only confers a survival benefit of a few months, and thus, discovery of new therapeutics is of utmost importance. In this review, we discuss the cell of origin of DMGs, as well as the underlying molecular mechanisms that contribute to their aggressivity and resistance to treatment. Additionally, we outline the current standard of care for DMG patients and the potential future therapeutics for this cancer that are currently being tested in preclinical and clinical trials.

Evaluation of two-stage designs of Phase 2 single-arm trials in glioblastoma: a systematic review

BACKGROUND

Due to economical and ethical reasons, the two-stage designs have been widely used for Phase 2 single-arm trials in oncology because the designs allow us to stop the trial early if the proposed treatment is likely to be ineffective. Nonetheless, none has examined the usage for published articles that had applied the two-stage designs in Phase 2 single-arm trials in brain tumor. A complete systematic review and discussions for overcoming design issues might be important to better understand why oncology trials have shown low success rates in early phase trials.

METHODS

We systematically reviewed published single-arm two-stage Phase 2 trials for patients with glioblastoma and high-grade gliomas (including newly diagnosed or recurrent). We also sought to understand how these two-stage trials have been implemented and discussed potential design issues which we hope will be helpful for investigators who work with Phase 2 clinical trials in rare and high-risk cancer studies including Neuro-Oncology. The systematic review was performed based on the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA)-statement. Searches were conducted using the electronic database of PubMed, Google Scholar and ClinicalTrials.gov for potentially eligible publications from inception by two independent researchers up to May 26, 2022. The followings were key words for the literature search as index terms or free-text words: "phase II trials", "glioblastoma", and "two-stage design". We extracted disease type and setting, population, therapeutic drug, primary endpoint, input parameters and sample size results from two-stage designs, and historical control reference, and study termination status.

RESULTS

Among examined 29 trials, 12 trials (41%) appropriately provided key input parameters and sample size results from two-stage design implementation. Among appropriately implemented 12 trials, discouragingly only 3 trials (10%) explained the reference information of historical control rates. Most trials (90%) used Simon's two-stage designs. Only three studies have been completed for both stages and two out of the three completed studies had shown the efficacy.

CONCLUSIONS

Right implementation for two-stage design and sample size calculation, transparency of historical control and experimental rates, appropriate selection on primary endpoint, potential incorporation of adaptive designs, and utilization of Phase 0 paradigm might help overcoming the challenges on glioblastoma therapeutic trials in Phase 2 trials.

Prediction of Cancer-Specific Survival of Brainstem Glioma in Children Based on Risk Stratification Model

Objective. To develop and authenticate a risk stratification framework and nomogram for ascertaining cancer-specific survival (CSS) among the pediatric brainstem gliomas. Methods. For patients less than 12 years, according to Surveillance, Epidemiology, and End Results (SEER), information from 1998 to 2016 is found in their databases. The survival outcomes, treatments, and demographic clinicopathologic conditions are scrutinized per the database validation, and training cohorts are divided and validated using multivariate Cox regression analysis. A nomogram was designed, and predominantly, the risk stratification conceptualization engaged selected tenets according to the multivariate analysis. The model’s authenticity was substantiated through C-index measure and calibration curves. Results. There are 806 pediatric concerns of histologically concluded brainstem glioma in the research. According to multivariate analysis, age, grade, radiotherapy, and race (with $P$ value < 0.05) depicted independent prognostic variations of the pediatric gliomas. The nomogram’s C-index was approximately 0.75 and an accompanied predictive capability for CSS. Conclusion. The nomogram constructed in this glioma’s context is the primary predictor of using risk stratification. A combination of nomograms with the risk stratification mechanism assists clinicians in monitoring high-risk individuals and engage targeted accessory treatment.

Current concepts in radiologic assessment of pediatric brain tumors during treatment, part 1

Pediatric brain tumors differ from those in adults by location, phenotype and genotype. In addition, they show dissimilar imaging characteristics before and after treatment. While adult brain tumor treatment effects are primarily assessed on MRI by measuring the contrast-enhancing components in addition to abnormalities on T2-weighted and fluid-attenuated inversion recovery images, these methods cannot be simply extrapolated to pediatric central nervous system tumors. A number of researchers have attempted to solve the problem of tumor assessment during treatment in pediatric neuro-oncology; specifically, the Response Assessment in Pediatric Neuro-Oncology (RAPNO) working group was recently established to deal with the distinct challenges in evaluating treatment-related changes on imaging, but no established criteria are available. In this article we review the current methods to evaluate brain tumor therapy and the numerous challenges that remain. In part 1, we examine the role of T2-weighted imaging and fluid-attenuated inversion recovery sequences, contrast enhancement, volumetrics and diffusion imaging techniques. We pay particular attention to several specific pediatric brain tumors, such as optic pathway glioma, diffuse midline glioma and medulloblastoma. Finally, we review the best means to assess leptomeningeal seeding.

Complete response and long-term survival (>20 years) of a child with tectal glioma: a case report

Tectal glioma is a midbrain tumor. The patient generally presents with symptoms related to increased intracranial pressure and requires treatment for hydrocephalus. No effective pharmacological treatments have yet been introduced. This report discusses a case of a 13-year-old male diagnosed with tectal glioma who obtained a complete response and long-term survival after the treatment with antineoplastons (ANP) in phase II trial. Prior treatment consisted of placement of a ventriculoperitoneal shunt. After 6 years of stabilization there had been an increase in tumor size with signs of malignant transformation. The patient received treatment with ANP A10 and AS2-1 infusions for 20 months, obtained a complete response, and was switched to maintenance with ANP capsules. All treatments were discontinued in December 2003. Adverse events according to CTCAE v3.0 included: hypernatremia (two events of grade 3, one event of grade 2, four events of grade 1), one case of fatigue (grade 2), and one allergic reaction (grade 1). Currently, over 20 years from his diagnosis and over 13 years from treatment start he is symptom-free and leads a normal life. This report indicates that it is possible to obtain long-term survival of a child with tectal glioma with currently available investigational treatment.