Project Summary/Abstract
The outcomes for patients with large B-cell lymphoma (LBCL) that are relapsed or refractory to frontline
therapy remain quite poor. While anti-CD19 chimeric antigen receptor (CAR19) T-cells have emerged as a
promising treatment option for this group of patients, over half of these patients still go on to exhibit disease
progression. The mechanisms through which resistance to CAR19 T-cell therapy develops, and factors
predictive of poor outcomes, have not yet been well characterized. In this proposal we seek to elucidate these
mechanisms with the ultimate goal of informing the design of improved immunotherapies that will result in better
outcomes for patients with LBCL.
Novel methods to profile tumor-derived cell-free DNA from the blood plasma of patients, also referred to
as circulating tumor DNA (ctDNA), have unlocked significant opportunities to monitor treatment response and
study tumor biology both prior to and after therapy. We recently applied one such method called Cancer
Personalized Profiling by Deep Sequencing (CAPP-Seq), a targeted sequencing approach for ctDNA detection
and profiling, to a cohort of patients with LBCL undergoing therapy with the CAR19 platform axicabtagene
ciloleucel (axi-cel). We found that ctDNA levels prior to and following CAR19 T-cell infusion were predictive of
response, and also identified several genes involved in B-cell lineage commitment and determination of the
tumor immune microenvironment that were recurrently altered in patients who developed progressive disease.
In this proposal we will build on this prior data by validating our findings in an independent cohort of
patients undergoing therapy with an alternate CAR19 platform (Aim 1). We will then assess the downstream
effects these alterations have on tumor phenotype and the tumor microenvironment. By integrating gene
expression data and cutting-edge immunophenotyping and computational tools, we will resolve the components
of the intratumoral immune milieu to gain a better understanding of how different immune cell populations
contribute to response and resistance (Aim 2). Finally, we will employ a novel organoid tissue culture system to
directly assess how alterations in these genes effect the interaction between CAR19 T-cells and tumor cells in
the context of an intact immune microenvironment (Aim 3). Ultimately, we hope that these studies will have
implications not only in development of improved CAR19 platforms for lymphoma, but also in the improvement
of immunotherapies for other cancer types as well.
This proposal will be carried out at the Stanford University School of Medicine, under the mentorship of
Ash Alizadeh, MD/PhD. Through completion of this proposal, I will gain the relevant experience in bioinformatics
and tumor immunology to successfully launch a career as an independent investigator focused on developing
and translating new immunotherapies for patients with lymphoma.