R & D:Network Biology: Mechanism-Based Drug Design
A key advantage of Merrimack’s validated Biochemical
Network Models is the ability to rapidly consider all of the
potential targets in the pathway in silico, and inexpensively
model and compare the variety of therapeutic strategies that can
be applied to those targets.
As an example, when considering targeting a receptor or receptor
system, several therapeutic strategies are possible, and many of
them have been proven in the clinic. One simple strategy is a ligand
sink, which binds and/or inactivates
free ligand. Another strategy might employ receptor antagonists
that bind to the receptor and physically prevent ligand from binding. More recent strategies include the
use of antibodies to modulate receptor internalization or prevent
receptor dimerization. An alternative
strategy could focus on the intracellular tyrosine kinase domain
of the receptor, inhibiting activation with a highly specific small
molecule. Rarely are these approaches
equally potent and, surprisingly, the best approach varies dramatically
from network to network.
Increasingly, investigators are interested in another alternative
approach – combining more than one targeted therapeutic. Our
models provide a unique and elegant tool to evaluate the effect
of combination therapies. We can rapidly identify potential
synergistic (or antagonistic) effects of combining therapeutics
that target multiple “nodes” in the pathway or even
two separate pathways.
The expression of network proteins varies among different organ
and tissue types and between diseased and normal tissue. This variation,
as well as genetic variation among patients, is also considered
by our models. As a result, we can easily consider
another important drug-development issue: target-specific toxicity
in non-target tissues, e.g. the heart and liver, by adapting the
model with expression data on network components in these tissues.