Diffuse midline glioma H3 K27-altered treatment

Diffuse midline glioma H3 K27-altered treatment

Stereotactic biopsy is being performed in some centers, and may become routine when therapies specifically targeted to these mutations become available.

Diffuse midline glioma H3 K27-altered have no effective treatment, and their location and diffuse nature render them inoperable. Radiation therapy remains the only standard of care for this devastating disease.

Until recently biopsies were considered not informative enough and therefore not recommended.

see GD2-CAR T cell therapy


Systemic administration of chemotherapeutic agents is often hindered by the blood brain barrier (BBB), and even drugs that successfully cross the barrier may suffer from unpredictable distributions. The challenge in treating this deadly disease relies on effective delivery of a therapeutic agent to the bulk tumor as well as infiltrating cells. Therefore, methods that can enhance drug delivery to the brain are of great interest. Convection-enhanced delivery (CED) is a strategy that bypasses the BBB entirely and enhances drug distribution by applying hydraulic pressure to deliver agents directly and evenly into a target region. This technique reliably distributes infusate homogenously through the interstitial space of the target region and achieves high local drug concentrations in the brain. Moreover, recent studies have also shown that continuous delivery of drug over an extended period of time is safe, feasible, and more efficacious than standard single session CED. Therefore, CED represents a promising technique for treating midline tumors with the H3K27M mutation 1).


Based on the molecular heterogeneity observed in this tumor type, personalized treatment is considered to substantially improve therapeutic options. Therefore, clinical evidence for therapy, guided by comprehensive molecular profiling, is urgently required. In this study, we analyzed feasibility and clinical outcomes in a cohort of 12 H3K27M glioma cases treated at two centers. Patients were subjected to personalized treatment either at primary diagnosis or disease progression and received backbone therapy including focal irradiation. Molecular analyses included whole-exome sequencing of tumor and germline DNA, RNA-sequencing, and transcriptomic profiling. Patients were monitored with regular clinical as well as radiological follow-up. In one case, liquid biopsy of cerebrospinal fluid (CSF) was used. Analyses could be completed in 83% (10/12) and subsequent personalized treatment for one or more additional pharmacological therapies could be recommended in 90% (9/10). Personalized treatment included inhibition of the PI3K/AKT/mTOR pathway (3/9), MAPK signaling (2/9), immunotherapy (2/9), receptor tyrosine kinase inhibition (2/9), and retinoic receptor agonist (1/9). The overall response rate within the cohort was 78% (7/9) including one complete remission, three partial responses, and three stable diseases. Sustained responses lasting for 28 to 150 weeks were observed for cases with PIK3CA mutations treated with either miltefosine or everolimus and additional treatment with trametinib/dabrafenib in a case with BRAFV600E mutation. Immune checkpoint inhibitor treatment of a case with increased tumor mutational burden (TMB) resulted in complete remission lasting 40 weeks. Median time to progression was 29 weeks. Median overall survival (OS) in the personalized treatment cohort was 16.5 months. Last, we compared OS to a control cohort (n = 9) showing a median OS of 17.5 months. No significant difference between the cohorts could be detected, but long-term survivors (>2 years) were only present in the personalized treatment cohort. Taken together, we present the first evidence of clinical efficacy and an improved patient outcome through a personalized approach at least in selected cases of H3K27M glioma 2).


Findings suggest that targeting PLK1 with small-molecule inhibitors, in combination with radiation therapy, will hold a novel strategy in the treatment of Diffuse intrinsic pontine glioma (DIPG) that warrants further investigation 3).


1)

Himes BT, Zhang L, Daniels DJ. Treatment Strategies in Diffuse Midline Gliomas With the H3K27M Mutation: The Role of Convection-Enhanced Delivery in Overcoming Anatomic Challenges. Front Oncol. 2019 Feb 8;9:31. doi: 10.3389/fonc.2019.00031. PMID: 30800634; PMCID: PMC6375835.
2)

Gojo J, Pavelka Z, Zapletalova D, Schmook MT, Mayr L, Madlener S, Kyr M, Vejmelkova K, Smrcka M, Czech T, Dorfer C, Skotakova J, Azizi AA, Chocholous M, Reisinger D, Lastovicka D, Valik D, Haberler C, Peyrl A, Noskova H, Pál K, Jezova M, Veselska R, Kozakova S, Slaby O, Slavc I, Sterba J. Personalized Treatment of H3K27M-Mutant Pediatric Diffuse Gliomas Provides Improved Therapeutic Opportunities. Front Oncol. 2020 Jan 10;9:1436. doi: 10.3389/fonc.2019.01436. PMID: 31998633; PMCID: PMC6965319.
3)

Amani V, Prince EW, Alimova I, Balakrishnan I, Birks D, Donson AM, Harris P, Levy JM, Handler M, Foreman NK, Venkataraman S, Vibhakar R. Polo-like Kinase 1 as a potential therapeutic target in Diffuse Intrinsic Pontine Glioma. BMC Cancer. 2016 Aug 18;16:647. doi: 10.1186/s12885-016-2690-6. PubMed PMID: 27538997.

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