Agilent - Breakthroughs in Immunotherapy- 2019 - 17

Breakthroughs in Immunotherapy

Often, functional potency assays are
designed without considering other cells
in the tumor microenvironment or the
tissues the disease affects. Considering
these factors during assay creation would
help better predict potency or efficacy in
the human patient.

facilities and laboratories. Assay readouts
should have a low coefficient of variation (CV) and a high signal-to-noise ratio.
Variability attributed to the cells, reagents,
instruments, platform devices if applicable,
such as microchips, and operators should
be minimized as much as possible.

"Ultimately, personalized medicine is the
objective," says Dr. Roy. "The goal is to
eventually design something that is better
than just taking into account the general
average conditions of patients. Using a
patient's biopsy for potency assays in
cancer cases would take into consideration patient-specific conditions, if not the
whole microenvironment. In other disease
that may not be possible."

"For example, in current methods, one
takes a tumor cell line and co-cultures the
CAR-T cells with it to determine that the
CAR-T cells recognize the tumor, express
the same molecule and kill the tumor
cells. Although this may be considered a
good functional assay, it does not reflect
the patient condition or the tumor microenvironment, which is especially relevant
in solid tumors," discusses Dr. Roy.

In addition, studying a large cohort of
patients during assay development would
help scientists better understand patient
variability.

These conditions can be incorporated
into the potency assay by co-culturing
with other cells from the tumor microenvironment or by creating a 3D culture. The
additional variables may provide a more
accurate in vivo behavioral prediction
but also leads to complexity when translating to manufacturing. While the current
method is simpler, it does not correlate
exactly with functionality.

Validation Considerations
Reproducibility, robustness and ease of
performance are critical to ensure assay
consistency across samples from multiple
17

| GENengnews.com

According to Dr. Lowdell, the potency
assay for an allogeneic cell product called
INKmune™ measures the activation of NK
cells. Since it is an off-the-shelf product,
the manufacturing process does not take
into account individual patients; therefore,
a prescreened donor pool of normal NK
cells is used to show activation. For autologous products, the only way to reduce or
control variability is to use standardized
targets or molecules.
Building in positive and negative controls
should also be part of assay qualification.
In autologous situations, variability within
the same product can be donor related.
For example, internal antibody-binding
bead standards can be used in select
flow cytometric assays. The antibodies
bind both to the beads and the cells. The
beads must fall into a defined region
indicating that the appropriate antibody
and amount were added, and that the
operator performed the assay correctly.
With internal controls, any irregularities
between samples can be attributed to
biological variation rather than technical
assay failure.
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Agilent - Breakthroughs in Immunotherapy- 2019

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