IsoPlexis eBook - 8

Polyfunctional Strength Offers a New Approach to Defining Quality in Cell Therapy

However, the CD4+ CAR-T cell PSI was in fact more highly
correlated with objective response of the patients than the
CD8+ CAR-T cell PSI. Moreover, the higher PSI in responding patients' CD4+ CAR-T samples was driven by multiple,
non-redundant cytokines, including the effector/anti-tumor
cytokines IFN-γ, and MIP-1α, stimulatory cytokine IL-8, and
inflammatory cytokine IL-17A.
In addition, grade ≥3 cytokine release syndrome was associated with polyfunctional T cells, and both grade ≥3 neurologic toxicity and antitumor efficacy were associated with
polyfunctional IL-17A-producing T cells suggesting that the
combination of frequency and cytokine production levels of
polyfunctional T cells in the product also are associated with
toxicity resulting from treatment with CAR T cells.
This study showed the potential power of PSI as a preinfusion biomarker for in vivo clinical outcome of CAR-T cell
treatment in patients, where other tested metrics have not
associated with outcome. Given the range of contributing
cytokines noted, PSI is effective as an overall, aggregated
cellular potency metric that does not require knowing the
specific subsets that are most correlated with outcome. (For
more information on the trial, visit and
reference registration number #NCT00924326.)
PSI teases out subtle differences in response, further narrows
down what drove differences in the index and identifies
additional biomarkers that strengthen the correlation with
clinical outcome.



Optimize: Uncovering Subtle Differences in
Bioprocessing for Manufacturing Optimization
As clinical applications for CAR-T cell therapy expand, cell
manufacturing incorporating closed-system, automated
instruments are supplanting traditional open-system, laborintensive culture methods. One of these closed systems,
the CliniMACS Prodigy (Miltenyi Biotec) was used to test
the duration of T-cell activation/viral transduction, and total
T-cell culture duration using an original and modified manufacturing method.
Data demonstrated that the modified manufacturing
method which terminated T-cell activation/transduction by
culture Day 3 resulted in reproducible and robust CAR-T cell
production, even in relatively more sensitive patient cells. In
addition, final product dose requirements were consistently
met by culture Day 7 when using this method, augmenting
process efficiency.
Specifically, the polyfunctional response to CD19 and CD22
antigen stimulation of CAR-T cell products generated was
compared between the two methods. PSI revealed clear
superiority of the new modified bispecific CAR-T manufacturing method in responding to CD19 and CD22 antigen
stimulation as reported by Srivastava et al. at the 2018 American Society of Hematology Annual Meeting.
Both CD4+ and CD8+ samples produced with the modified
method showed significant increases in PSI, clearly demonstrating that this method significantly improved the overall

quality of the CAR-T cell products. Moreover, these data
allowed a better understanding of the drivers of this polyfunctional upregulation for better characterization of the products,
and demonstrated that PSI provides an effective method for
characterizing cell therapy products and their potency.
A Powerful Unique Metric to Discover,
Optimize, Predict
PSI is a powerful and unique tool with a wide range of applications in engineered immune cell therapy research and
development. The metric can be used in preclinical discovery to understand correlations with in vivo response, in
clinical outcome correlates, including the effectiveness of PSI
as a potential pre-infusion biomarker for CAR-T cell therapy
patient outcome, and product and manufacturing optimization, where PSI can reveal distinct differences in bioprocessing methods for process optimization. n

IsoPlexis eBook

Table of Contents for the Digital Edition of IsoPlexis eBook

IsoPlexis eBook - 1
IsoPlexis eBook - 2
IsoPlexis eBook - Contents
IsoPlexis eBook - 4
IsoPlexis eBook - 5
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IsoPlexis eBook - 7
IsoPlexis eBook - 8
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IsoPlexis eBook - 15