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

Indoximod-based chemo-immunotherapy for pediatric brain tumors: A first-in-children phase I trial

BACKGROUND

Recurrent brain tumors are the leading cause of cancer death in children. Indoleamine 2,3-dioxygenase (IDO) is a targetable metabolic checkpoint that, in preclinical models, inhibits anti-tumor immunity following chemotherapy.

METHODS

We conducted a phase I trial (NCT02502708) of the oral IDO-pathway inhibitor indoximod in children with recurrent brain tumors or newly diagnosed diffuse intrinsic pontine glioma (DIPG). Separate dose-finding arms were performed for indoximod in combination with oral temozolomide (200 mg/m2/day x 5 days in 28-day cycles), or with palliative conformal radiation. Blood samples were collected at baseline and monthly for single-cell RNA-sequencing with paired single-cell T cell receptor sequencing.

RESULTS

Eighty-one patients were treated with indoximod-based combination therapy. Median follow-up was 52 months (range 39-77 months). Maximum tolerated dose was not reached, and the pediatric dose of indoximod was determined as 19.2 mg/kg/dose, twice daily. Median overall survival was 13.3 months (n = 68, range 0.2-62.7) for all patients with recurrent disease and 14.4 months (n = 13, range 4.7-29.7) for DIPG. The subset of n = 26 patients who showed evidence of objective response (even a partial or mixed response) had over 3-fold longer median OS (25.2 months, range 5.4-61.9, p = 0.006) compared to n = 37 nonresponders (7.3 months, range 0.2-62.7). Four patients remain free of active disease longer than 36 months. Single-cell sequencing confirmed emergence of new circulating CD8 T cell clonotypes with late effector phenotype.

CONCLUSIONS

Indoximod was well tolerated and could be safely combined with chemotherapy and radiation. Encouraging preliminary evidence of efficacy supports advancing to Phase II/III trials for pediatric brain tumors.

Translational considerations for immunotherapy clinical trials in pediatric neuro-oncology

While immunotherapy for pediatric cancer has made great strides in recent decades, including the FDA approval of agents such as dinutuximab and tisgenlecleucel, these successes have rarely impacted children with pediatric central nervous system (CNS) tumors. As our understanding of the biological underpinnings of these tumors evolves, new immunotherapeutics are undergoing rapid clinical translation specifically designed for children with CNS tumors. Most recently, there have been notable clinical successes with oncolytic viruses, vaccines, adoptive cellular therapy, and immune checkpoint inhibition. In this article, the immunotherapy working group of the Pacific Pediatric Neuro-Oncology Consortium (PNOC) reviews the current and future state of immunotherapeutic CNS clinical trials with a focus on clinical trial development. Based on recent therapeutic trials, we discuss unique immunotherapy clinical trial challenges, including toxicity considerations, disease assessment, and correlative studies. Combinatorial strategies and future directions will be addressed. Through internationally collaborative efforts and consortia, we aim to direct this promising field of immuno-oncology to the next frontier of successful application against pediatric CNS tumors.

Pomalidomide-induced lung injury: A case report

RATIONALE

Pomalidomide is an immunomodulatory imide drug used in multiple myeloma and in Kaposi sarcoma.

PATIENT CONCERNS

A 72-years-old male, treated for multiple myeloma with dexamethasone, pomalidomide and daratumumab, presented dyspnea, hypoxemia, biological inflammatory syndrome, ground glass opacities on computed tomography scan (CT-scan) and lymphocytic and eosinophilic alveolitis, with no specific cytologic or microbiological findings, 2 months after pomalidomide initiation.

INTERVENTION AND OUTCOME

Antibiotics were started after bronchoscopy. No improvement was noted in dyspnea and biological inflammatory syndrome after 5 days of treatment. Pomalidomide was then discontinued, with continuation of Daratumumab-Dexamethasone, resulting in a rapid recovery of symptoms and CT-scan anomalies. No recurrence of dyspnea was observed during the 15 months of follow-up.

DIAGNOSES

Pomalidomide-induced lung injury.

LESSONS

Pomalidomide-induced lung injury is a rare and serious adverse event that can occur early after Pomalidomide introduction. As pomalidomide use is increasing, the identification of drug toxicity as a possible cause of lung injury appears important. We report a rapid recovery of symptoms and CT-scan anomalies after pomalidomide discontinuation.

Immunotherapy for the treatment of pediatric brain tumors: a narrative review

BACKGROUND AND OBJECTIVE

The goal of this narrative review is to report and summarize the completed pediatric immunotherapy clinical trials for primary CNS tumors. Pediatric central nervous system (CNS) tumors are the most common cause of pediatric solid cancer in children aged 0 to 14 years and the leading cause of cancer mortality. Survival rates for some pediatric brain tumors have improved, however, there remains a large portion of pediatric brain tumors with poor survival outcomes despite advances in treatment. Cancer immunotherapy is a growing field that has shown promise in the treatment of pediatric brain tumors that have historically shown a poor response to treatment. This narrative review provides a summary and discussion of the published literature focused on treating pediatric brain tumors with immunotherapy.

METHODS

MEDLINE via PubMed, Embase and Scopus via Elsevier were searched. The search utilized a combination of keywords and subject headings to include pediatrics, brain tumors, and immunotherapies. Manuscripts included in the analysis included completed clinical studies using any immunotherapy intervention with a patient population that consisted of at least half pediatric patients (<18 years) with primary CNS tumors. Conference abstracts were excluded as well as studies that did not include completed safety or primary outcome results.

KEY CONTENT AND FINDINGS

Search results returned 1,494 articles. Screening titles and abstracts resulted in 180 articles for full text review. Of the 180 articles, 18 were included for analysis. Another two articles were ultimately included after review of references and inclusion of newly published articles, for a total of 20 included articles. Immunotherapies included dendritic cell vaccines, oncolytic virotherapy/viral immunotherapy, chimeric antigen receptor (CAR) T-cell therapy, peptide vaccines, immunomodulatory agents, and others.

CONCLUSIONS

In this review, 20 published articles were highlighted which use immunotherapy in the treatment of primary pediatric brain tumors. To date, most of the studies published utilizing immunotherapy were phase I and pilot studies focused primarily on establishing safety and maximum dose-tolerance and toxicity while monitoring survival endpoints. With established efficacy and toxicity profiles, future trials may progress to further understanding the overall survival and quality of life benefits to pediatric patients with primary brain tumors.

Diffuse Intrinsic Pontine Glioma: Molecular Landscape, Evolving Treatment Strategies and Emerging Clinical Trials

Diffuse intrinsic pontine glioma (DIPG) is a type of intrinsic brainstem glial tumor that occurs primarily in the pediatric population. DIPG is initially diagnosed based on clinical symptoms and the characteristic location on imaging. Histologically, these tumors are characterized by a heterogenous population of cells with multiple genetic mutations and high infiltrative capacity. The most common mutation seen in this group is a lysine to methionine point mutation seen at position 27 (K27M) within histone 3 (H3). Tumors with the H3 K27M mutation, are considered grade 4 and are now categorized within the H3 K27-altered diffuse midline glioma category by World Health Organization classification. Due to its critical location and aggressive nature, DIPG is resistant to the most eradicative treatment and is universally fatal; however, modern advances in the surgical techniques resulting in safe biopsy of the lesion have significantly improved our understanding of this disease at the molecular level. Genomic analysis has shown several mutations that play a role in the pathophysiology of the disease and can be targeted therapeutically. In this review, we will elaborate on DIPG from general aspects and the evolving molecular landscape. We will also review innovative therapeutic options that have been trialed along with new promising treatments on the horizon.

Transcriptomic Portraits and Molecular Pathway Activation Features of Adult Spinal Intramedullary Astrocytomas

In this study, we report 31 spinal intramedullary astrocytoma (SIA) RNA sequencing (RNA-seq) profiles for 25 adult patients with documented clinical annotations. To our knowledge, this is the first clinically annotated RNA-seq dataset of spinal astrocytomas derived from the intradural intramedullary compartment. We compared these tumor profiles with the previous healthy central nervous system (CNS) RNA-seq data for spinal cord and brain and identified SIA-specific gene sets and molecular pathways. Our findings suggest a trend for SIA-upregulated pathways governing interactions with the immune cells and downregulated pathways for the neuronal functioning in the context of normal CNS activity. In two patient tumor biosamples, we identified diagnostic KIAA1549-BRAF fusion oncogenes, and we also found 16 new SIA-associated fusion transcripts. In addition, we bioinformatically simulated activities of targeted cancer drugs in SIA samples and predicted that several tyrosine kinase inhibitory drugs and thalidomide analogs could be potentially effective as second-line treatment agents to aid in the prevention of SIA recurrence and progression.

Immunotherapies for Pediatric Solid Tumors: A Targeted Update

There are encouraging signs in our collective progress to leverage the immune system to treat pediatric cancers. Here, we summarize interim successes in cancer immunotherapy and opportunities to translate from the adult world to pediatrics, and highlight challenges that could benefit from additional development, focusing on solid tumors. Just a decade ago, other than antibodies targeting disialoganglioside (GD2) in neuroblastoma, pediatric cancer immunotherapy was mostly relegated to obscure preclinical studies in a few academic labs. Today there are numerous clinical trials of a variety of antibody, cellular, gene, and viral therapies and vaccines designed to either promote antitumor immunity or specifically attack validated immunotherapy targets. Understanding those targets and their pediatric relevance is paramount. While much work is underway to evaluate the utility of numerous immunologic targets, the lack of regulatory approvals is emblematic of the challenges that remain. Herein we focus our review on the most promising targeted immunotherapies in clinical trials for children.

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.