Vali Barsan, MD is an Instructor in the Division of Pediatric Hematology, Oncology, and Stem Cell Transplantation at Stanford University School of Medicine. Dr. Barsan obtained his BS in Bioengineering at UC San Diego Jacobs School of Engineering and then joined Illumina as an engineer to develop and optimize next generation sequencing tools. He earned his MD at Baylor College of Medicine where he studied the biology of cancer metastasis through molecular techniques in the Mani Lab at MD Anderson Cancer Center. Dr. Barsan completed residency in Pediatrics at UC San Diego and fellowship in Pediatric Hematology/Oncology at Stanford University. He is focused on developing and translating genomic technologies in oncology to implement personalized therapy and study mechanisms of effective cancer immunity.
- Pediatric Hematology-Oncology
- Cancer Immunology and Immunotherapy
Honors & Awards
Anne T. and Robert M. Bass Endowed Fellow, Stanford Maternal and Child Health Research Institute (MCHRI) (2019 - 2021)
Medical Education: Baylor College of Medicine (2015) TX
Fellowship: Stanford University Pediatric Hematology Oncology Fellowship (2021) CA
Board Certification: American Board of Pediatrics, Pediatrics (2019)
Residency, UC San Diego, Pediatrics (2018)
Graduate Student Research, MD Anderson Cancer Center, Department of Translational Molecular Pathology, Mani Lab (2015)
MD, Baylor College of Medicine (2015)
BS, UC San Diego, Bioengineering (2009)
Current Research and Scholarly Interests
Adoptive T cell immunotherapy entails engineering immune cells to recognize cancer-specific antigens and target them for destruction. Barriers to efficacy can arise from both tumor antigen related as well as T cell related features. I am interested developing noninvasive molecular tools that enable us to understanding these relationships to improve the clinical application and development of cellular immunotherapeutics.
Simultaneous monitoring of disease and microbe dynamics through plasma DNA sequencing in pediatric patients with acute lymphoblastic leukemia.
2022; 8 (16): eabj1360
Treatment of acute lymphoblastic leukemia (ALL) necessitates continuous risk assessment of leukemic disease burden and infections that arise in the setting of immunosuppression. This study was performed to assess the feasibility of a hybrid capture next-generation sequencing panel to longitudinally measure molecular leukemic disease clearance and microbial species abundance in 20 pediatric patients with ALL throughout induction chemotherapy. This proof of concept helps establish a technical and conceptual framework that we anticipate will be expanded and applied to additional patients with leukemia, as well as extended to additional cancer types. Molecular monitoring can help accelerate the attainment of insights into the temporal biology of host-microbe-leukemia interactions, including how those changes correlate with and alter anticancer therapy efficacy. We also anticipate that fewer invasive bone marrow examinations will be required, as these methods improve with standardization and are validated for clinical use.
View details for DOI 10.1126/sciadv.abj1360
View details for PubMedID 35442732
GD2-CAR T cell therapy for H3K27M-mutated diffuse midline gliomas.
Diffuse intrinsic pontine glioma (DIPG) and other H3K27M-mutated diffuse midline gliomas (DMG) are universally lethal paediatric central nervous system tumours1. We previously discovered that the disialoganglioside GD2 is highly expressed on H3K27M-mutant glioma cells and demonstrated promising preclinical efficacy of GD2-directed chimeric antigen receptor (CAR) T cells2, providing the rationale for a first-in-human Phase 1 clinical trial (NCT04196413). Because CAR T-cell-induced brainstem inflammation can result in obstructive hydrocephalus, increased intracranial pressure, and dangerous tissue shifts, neurocritical care precautions were incorporated. Here we present the clinical experience from the first four patients with H3K27M-mutant DIPG/DMG treated with GD2-CAR T cells (GD2-CART) at dose level 1 (1e6 GD2-CAR T cells/kg administered intravenously). Patients who exhibited clinical benefit were eligible for subsequent GD2-CAR T infusions administered intracerebroventricularly3. Toxicity was largely related to tumor location and reversible with intensive supportive care. On-target, off-tumor toxicity was not observed. Three of four patients exhibited clinical and radiographic improvement. Proinflammatory cytokines were increased in plasma and cerebrospinal fluid (CSF). Transcriptomic analyses of 65,598 single cells from CAR T cell products and CSF elucidate heterogeneity in response between subjects and administration routes. These early results underscore the promise of this approach for H3K27M+ DIPG/DMG therapy.
View details for DOI 10.1038/s41586-022-04489-4
View details for PubMedID 35130560
Disease Burden Affects Outcomes in Pediatric and Young Adult B-Cell Lymphoblastic Leukemia After Commercial Tisagenlecleucel: A Pediatric Real-World Chimeric Antigen Receptor Consortium Report.
Journal of clinical oncology : official journal of the American Society of Clinical Oncology
PURPOSE: Tisagenlecleucel is a CD19-specific chimeric antigen receptor T-cell therapy, US Food and Drug Administration-approved for children, adolescents, and young adults (CAYA) with relapsed and/or refractory (RR) B-cell acute lymphoblastic leukemia (B-ALL). The US Food and Drug Administration registration for tisagenlecleucel was based on a complete response (CR) rate of 81%, 12-month overall survival (OS) of 76%, and event-free survival (EFS) of 50%. We report clinical outcomes and analyze covariates of outcomes after commercial tisagenlecleucel.METHODS: We conducted a retrospective, multi-institutional study of CAYA with RR B-ALL across 15 US institutions, who underwent leukapheresis shipment to Novartis for commercial tisagenlecleucel. A total of 200 patients were included in an intent-to-treat response analysis, and 185 infused patients were analyzed for survival and toxicity.RESULTS: Intent-to-treat analysis demonstrates a 79% morphologic CR rate (95% CI, 72 to 84). The infused cohort had an 85% CR (95% CI, 79 to 89) and 12-month OS of 72% and EFS of 50%, with 335 days of median follow-up. Notably, 48% of patients had low-disease burden (< 5% bone marrow lymphoblasts, no CNS3, or other extramedullary disease), or undetectable disease, pretisagenlecleucel. Univariate and multivariate analyses associate high-disease burden (HB, ≥ 5% bone marrow lymphoblasts, CNS3, or non-CNS extramedullary) with inferior outcomes, with a 12-month OS of 58% and EFS of 31% compared with low-disease burden (OS; 85%, EFS; 70%) and undetectable disease (OS; 95%, EFS; 72%; P < .0001 for OS and EFS). Grade ≥ 3 cytokine release syndrome and neurotoxicity rates were 21% and 7% overall and 35% and 9% in patients with HB, respectively.CONCLUSION: Commercial tisagenlecleucel in CAYA RR B-ALL demonstrates efficacy and tolerability. This first analysis of commercial tisagenlecleucel stratified by disease burden identifies HB preinfusion to associate with inferior OS and EFS and increased toxicity.
View details for DOI 10.1200/JCO.20.03585
View details for PubMedID 34882493
GD2 CAR T cells mediate clinical activity and manageable toxicity in children and young adults with DIPG and H3K27M-mutated diffuse midline gliomas.
AMER ASSOC CANCER RESEARCH. 2021
View details for Web of Science ID 000680263501014
- SINGLE CELL RNA SEQUENCING FROM THE CSF OF SUBJECTS WITH H3K27M+DIPG/DMG TREATED WITH GD2 CAR T-CELLULAR THERAPY OXFORD UNIV PRESS INC. 2021: 39
- GD2 CAR T-CELLS MEDIATE CLINICAL ACTIVITY AND MANAGEABLE TOXICITY IN CHILDREN AND YOUNG ADULTS WITH H3K27M-MUTATED DIPG AND SPINAL CORD DMG OXFORD UNIV PRESS INC. 2021: 49-50
- GENERALIZABILITY OF POTENTIAL BIOMARKERS OF RESPONSE TO CTLA-4 AND PD-1 BLOCKADE THERAPY IN CANCER BMJ PUBLISHING GROUP. 2020: A46–A47
- CONSTRUCTION OF THE IMMUNE LANDSCAPE OF DURABLE RESPONSE TO CHECKPOINT BLOCKADE THERAPY BY INTEGRATING PUBLICLY AVAILABLE DATASETS BMJ PUBLISHING GROUP. 2020: A5–A6
Prospects and Challenges for Use of CAR T Cell Therapies in Solid Tumors.
Expert opinion on biological therapy
Introduction: Chimeric antigen receptor (CAR) T cell therapy has provided patients with relapsed/refractory B cell malignancies with a new therapeutic option, but this class of therapeutics has not demonstrated consistent therapeutic benefit in solid tumors.Areas Covered: Here we review the literature to identify numerous factors that contribute to this discrepancy, using pediatric cancers as a platform to understand these limitations. We discuss an inability to target highly and homogenously expressed lineage-associated antigens due to risks of on-target, off-tumor toxicity, T cell dysfunction related to T cell exhaustion and the suppressive tumor microenvironment (TME), and inefficient CAR T cell trafficking into solid tumors. As our understanding of the biology of CAR T cells improves and innovations in engineering CAR platforms emerge, next generation CAR T cell therapeutics designed to overcome these challenges will enter the clinic for testing.Expert Opinion: New approaches to address the challenges that have limited the efficacy of CAR T cell therapeutics in solid tumors are emerging. These include next-generation CAR T cell engineering to overcome antigen heterogeneity, to mitigate T cell exhaustion and to prevent suppression by the TME, and novel approaches for regional delivery to overcome limitations in tumor T cell trafficking.
View details for DOI 10.1080/14712598.2020.1738378
View details for PubMedID 32125191
Immunotherapy for the Treatment of Acute Lymphoblastic Leukemia.
Current oncology reports
2020; 22 (2): 11
PURPOSE OF REVIEW: Immunotherapy for the treatment of acute lymphoblastic leukemia (ALL) broadens therapeutic options beyond chemotherapy and targeted therapy. Here, we review the use of monoclonal antibody-based drugs and cellular therapies to treat ALL. We discuss the challenges facing the field regarding the optimal timing and sequencing of these therapies in relation to other treatment options as well as considerations of cost effectiveness.RECENT FINDINGS: By early identification of patients at risk for leukemic relapse, monoclonal antibody and cellular immunotherapies can be brought to the forefront of treatment options. Novel CAR design and manufacturing approaches may enhance durable patient response. Multiple clinical trials are now underway to evaluate the sequence and timing of monoclonal antibody, cellular therapy, and/or stem cell transplantation. The biologic and clinical contexts in which immunotherapies have advanced the treatment of ALL confer optimism that more patients will achieve durable remissions. Immunotherapy treatments in ALL will expand through rationally targeted approaches alongside advances in CAR T cell therapy design and clinical experience.
View details for DOI 10.1007/s11912-020-0875-2
View details for PubMedID 31997022
Toward a comprehensive view of cancer immune responsiveness: a synopsis from the SITC workshop.
Journal for immunotherapy of cancer
2019; 7 (1): 131
Tumor immunology has changed the landscape of cancer treatment. Yet, not all patients benefit as cancer immune responsiveness (CIR) remains a limitation in a considerable proportion of cases. The multifactorial determinants of CIR include the genetic makeup of the patient, the genomic instability central to cancer development, the evolutionary emergence of cancer phenotypes under the influence of immune editing, and external modifiers such as demographics, environment, treatment potency, co-morbidities and cancer-independent alterations including immune homeostasis and polymorphisms in the major and minor histocompatibility molecules, cytokines, and chemokines. Based on the premise that cancer is fundamentally a disorder of the genes arising within a cell biologic process, whose deviations from normality determine the rules of engagement with the host's response, the Society for Immunotherapy of Cancer (SITC) convened a task force of experts from various disciplines including, immunology, oncology, biophysics, structural biology, molecular and cellular biology, genetics, and bioinformatics to address the complexity of CIR from a holistic view. The task force was launched by a workshop held in San Francisco on May 14-15, 2018 aimed at two preeminent goals: 1) to identify the fundamental questions related to CIR and 2) to create an interactive community of experts that could guide scientific and research priorities by forming a logical progression supported by multiple perspectives to uncover mechanisms of CIR. This workshop was a first step toward a second meeting where the focus would be to address the actionability of some of the questions identified by working groups. In this event, five working groups aimed at defining a path to test hypotheses according to their relevance to human cancer and identifying experimental models closest to human biology, which include: 1) Germline-Genetic, 2) Somatic-Genetic and 3) Genomic-Transcriptional contributions to CIR, 4) Determinant(s) of Immunogenic Cell Death that modulate CIR, and 5) Experimental Models that best represent CIR and its conversion to an immune responsive state. This manuscript summarizes the contributions from each group and should be considered as a first milestone in the path toward a more contemporary understanding of CIR. We appreciate that this effort is far from comprehensive and that other relevant aspects related to CIR such as the microbiome, the individual's recombined T cell and B cell receptors, and the metabolic status of cancer and immune cells were not fully included. These and other important factors will be included in future activities of the taskforce. The taskforce will focus on prioritization and specific actionable approach to answer the identified questions and implementing the collaborations in the follow-up workshop, which will be held in Houston on September 4-5, 2019.
View details for DOI 10.1186/s40425-019-0602-4
View details for PubMedID 31113486
Clinical Impact of Next-generation Sequencing in Pediatric Neuro-Oncology Patients: A Single-institutional Experience.
2019; 11 (12): e6281
The implementation of next-generation sequencing (NGS) in pediatric neuro-oncology may impact diagnosis, prognosis, therapeutic strategies, clinical trial enrollment, and germline risk. We retrospectively analyzed 58 neuro-oncology patients (31 boys, 27 girls, average age 7.4 years) who underwent NGS tumor profiling using a single commercially available platform on paraffin-embedded tissue obtained at diagnosis (20 low-grade gliomas, 12 high-grade gliomas, 11 embryonal tumors, four ependymal tumors, three meningeal tumors, and eight other CNS tumors) from May 2014 to December 2016. NGS results were analyzed for actionable mutations, variants of unknown significance and clinical impact. Seventy-four percent of patients (43 of 57) had actionable mutations; 26% had only variants of uncertain significance (VUS). NGS findings impacted treatment decisions in 55% of patients; 24% were given a targeted treatment based on NGS findings. Seven of eight patients with low-grade tumors treated with targeted therapy (everolimus, trametinib, or vemurafenib) experienced partial response or stable disease. All high-grade tumors had progressive disease on targeted therapy. Forty percent of patients had a revision or refinement of their diagnosis, and nine percent of patients were diagnosed with a previously unconfirmed cancer predisposition syndrome. Turnaround time between sample shipment and report generation averaged 13.4 ± 6.4 days. One sample failed due to insufficient DNA quantity. Our experience highlights the feasibility and clinical utility of NGS in the management of pediatric neuro-oncology patients. Future prospective clinical trials using NGS are needed to establish efficacy.
View details for DOI 10.7759/cureus.6281
View details for PubMedID 31827999
View details for PubMedCentralID PMC6892579
NIVOLUMAB IN THE TREATMENT OF RECURRENT OR REFRACTORY PEDIATRIC BRAIN TUMORS: A SINGLE INSTITUTIONAL EXPERIENCE
OXFORD UNIV PRESS INC. 2018: 100
View details for Web of Science ID 000438339000328
- Primer on Cancer Immunotherapy and the Targeting of Native Proteins Early Phase Cancer Immunotherapy Springer. 2018
Long-term follow-up and pregnancy after complete sacrectomy with lumbopelvic reconstruction: case report and literature review
BMC PREGNANCY AND CHILDBIRTH
2016; 16: 1
Sacrectomy remains a technically complex procedure for resection of malignant pelvic neoplasia. Commonly, postoperative complications include permanent neurological deficits. Only a few studies have reported the long-term functional outcomes of patients who had undergone sacrectomy.We previously reported on the utilization of complete sacrectomy and lumbopelvic reconstruction for the management of primary myofibroblastic sarcoma of the sacrum and ilium in a 15-year-old female patient. In this report, we update her postoperative course with an additional 5 years of follow-up and Health-Related Quality of Life (HRQoL) outcomes. During this time period, she gave birth to two healthy full-term babies.To the best of our knowledge, this is the first report of pregnancy after total sacrectomy and lumbopelvic reconstruction. We outline some of the challenges in the obstetrical management of this patient.
View details for PubMedID 26728010
A novel embryonic plasticity gene signature that predicts metastatic competence and clinical outcome
2015; 5: 11766
Currently, very few prognosticators accurately predict metastasis in cancer patients. In order to complete the metastatic cascade and successfully colonize distant sites, carcinoma cells undergo dynamic epithelial-mesenchymal-transition (EMT) and its reversal, mesenchymal-epithelial-transition (MET). While EMT-centric signatures correlate with response to therapy, they are unable to predict metastatic outcome. One reason is due to the wide range of transient phenotypes required for a tumor cell to disseminate and recreate a similar histology at distant sites. Since such dynamic cellular processes are also seen during embryo development (epithelial-like epiblast cells undergo transient EMT to generate the mesoderm, which eventually redifferentiates into epithelial tissues by MET), we sought to utilize this unique and highly conserved property of cellular plasticity to predict metastasis. Here we present the identification of a novel prognostic gene expression signature derived from mouse embryonic day 6.5 that is representative of extensive cellular plasticity, and predicts metastatic competence in human breast tumor cells. This signature may thus complement conventional clinical parameters to offer accurate prediction for outcome among multiple classes of breast cancer patients.
View details for PubMedID 26123483