Bioinstructive Scaffolds for Potent and Affordable CAR-T Cell Therapy Against Brain Tumors

PROJECT SUMMARY
Glioblastoma multiforme (GBM) is a fatal and difficult to treat brain tumor with a dismal median survival of less
than 2 years. Standard therapy consists of surgical tumor resection, radiotherapy, and temozolomide, which only
delay tumor recurrence. Recent success of CAR T cell therapy against Non-Hodgkin’s Lymphomas have gener-
ated significant excitement for the application of CAR T cells in GBM and several clinical trials have demonstrated
efficacy of CAR T cells in patients with GBM. However, both immunosuppression and the blood brain barrier act
as major impediments limiting CAR T cell efficacy in glioblastoma. Preclinical trials with localized administration
for CAR T cells via intratumoral or intraventricular routes enhance CAR T cell infiltration to brain tumor and
outperforms i.v. infusions. With locoregional control, CAR T cells are infused into the resected tumor cavity,
followed by repeated infusions into the ventricular system. Multiple administrations are necessary to maintain a
larger dose of CAR T cells without causing toxicity and to enhance persistence of functional CAR T cells over a
longer time. However, this repetitive dosing is a major obstacle to clinical translation of CAR T cells against GBM.
CAR T cell manufacturing takes weeks and carries high costs - ~$500,000 per dose. The long manufacturing
time creates delays of weeks to months to infuse CAR T cells to patients with rapidly progressing disease.
Additionally, lengthy ex vivo manipulations create CAR T cells with heterogeneous composition and terminal
differentiation, limiting their engraftment and persistence. Taken together, the many shortfalls of current CAR T
cell manufacturing urgently demand development of innovative tools to reduce manufacturing time and provide
optimal CAR T cell phenotype and distribution. In this proposal, we describe the application of Multifunctional
Alginate Scaffold for T cell Engineering and Release (MASTER) for use in GBM. MASTER will be implanted in
the surgical cavity of GBM to generate and release CAR T cells in vivo with improved efficacy and persistence.
Based on significant published and preliminary data, we show that MASTER provides bio-instructive ques to
activate, transduce, expand, and release fully functional CAR T cells in vivo. The scaffold includes anchored
activating antibodies and interleukins to guarantee T cell activation and proliferation. Scaffold macroporosity
facilitates homogeneous distribution of T cells, creates an interface for interaction between viruses and T cells,
and enables in vivo release of fully functional CAR T cells. MASTER reduces CAR T manufacturing times from
weeks to a single day, substantially reducing costs. We demonstrate in preliminary data and propose further that
MASTER seeded with naïve PBMCs and anti-B7H3 CAR-encoding retrovirus will be implanted in the resection
cavity of a brain tumor. B7H3 is overexpressed in brain tumors and serves as a promising therapeutic target for
CAR T cell therapy. This approach could have enormous clinical impact by significantly reducing therapy costs
and dramatically expanding the patient population benefiting from CAR T cell therapy. These studies will provide
a foundational technology platform for CAR T cell manufacturing and promote widespread patient access.