www.clinicalomics.com November/December 2017 Clinical OMICs 11
T
wo FDA drug approvals earlier
this year point to an encouraging
future for "precision medicine" — an
approach for disease treatment that
tailors medical therapies, including
medications, to the needs of individ-
ual patients. These approvals involve
diseases resulting from particular
genetic characteristics identified by
laboratory testing.
• In mid-May, FDA announced
that we expanded the approval
of Kalydeco (ivacaftor), enabling
a larger number of patients with
cystic fibrosis (CF) to benefit from
the drug. The expanded approval
includes CF patients with one of 23
additional rare mutations. Kalydeco
is now indicated for 33 CF
mutations, up from 10 previously.
• Also in May, we announced
expanded approval for Keytruda
(pembrolizumab) to treat patients
whose cancers have a specific
genetic feature. This is the first
time FDA has approved a cancer
treatment based on a genetic
feature, rather than the location
in the body where the cancer
originated.
FDA has approved many more
advances in precision medicines, also
called "targeted therapies." In the past
three years alone, our Center for Drug
Evaluation and Research has approved
more than 25 new drugs that benefit
patients with specific genetic char-
acteristics. And we have approved
many more new uses — also based on
specific genetic characteristics — for
drugs already on the market. Some of
these drug approvals are for patients
with rare genetic disorders. Others are
new targeted therapies to treat cancer,
hepatitis C, or HIV. Medication dosing
for specific diseases may also be tai-
lored to the individual.
Precision medicine holds great
promise, but to continue developing
targeted therapies, we will need sci-
entific advances in the use and devel-
opment of biomarkers. Biomarkers
are indicators in the body that can
be measured—like blood pressure,
blood sugar, and tumor size. Tests to
identify genetic variants are another
form of biomarker. Biomarkers can
enable health care professionals and
researchers to identify patients at
risk of disease, determine the stage
of a disease, and predict the likeli-
hood that a patient will benefit from
a drug. They also play a role in drug
development. A particular biomarker,
for example, can be used to identify
appropriate candidates for a clinical
trial, such as those patients likely to
respond to treatment. This can make
it easier and faster to recruit patients
and may result in a shorter time for
drug approval. In a similar way,
biomarkers can sometimes identify
positive treatment effects before tra-
ditional clinical endpoints would. For
instance, biomarkers might show a
tumor shrinking before improvement
in a patient's condition is detected. So,
using biomarkers in clinical trials can
speed up the time it takes for an inves-
tigative drug to reach a patient.
The ability to identify useful bio-
markers depends on how well scien-
tists understand the disease they are
seeking to treat. In some areas, such
as cancer and infectious diseases, we
have made real progress in under-
standing how these diseases develop
and how to treat them with drug ther-
apy. FDA continues to encourage drug
developers to use strategies based on
biomarkers. One way we do that is
by ensuring that a given biomarker is
really able to single out those patients
who are likely to respond to a spe-
cific drug. Another way is using bio-
markers to identify people whose
disease is progressing rapidly. Beyond
working on biomarkers for individ-
ual products, FDA also works with
stakeholders and scientific consor-
tia in qualifying biomarkers that can
be used in the development of many
drugs. Once qualified, these biomark-
ers may be used in the specified man-
ner by any drug sponsor.
New provisions under the recently
passed 21st Century Cures Act provide
direction and opportunity for FDA to
strengthen the science of biomarkers
and to advance precision medicine. We
believe it is important to make drugs
such as Kalydeco and Keytruda avail-
able to as many patients as can benefit
from them. FDA is actively pursuing
more advances in targeted therapies.
Errata: On page 29 of the October-
November issue, Eric Ostertag was incor-
rectly identified as the CEO of Caribou
Biosciences. He is the CEO of Poseida
Therapeutics, and we incorrectly stated
that Jennifer Doudna left Editas to found
Caribou Biosciences, when the company
was already operating when Doudna
joined. We regret these errors.
Recent FDA Approvals Demonstrate
Promise of Precision Medicine
OP-ED
Janet Woodcock, M.D.
Director, FDA Center for
Drug Evaluation and Research