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THE
CUTTING EDGE
news + research
A Game-changer in the Fight against Melanoma
White blood cells attempt to attack a deadly
melanoma cancer tumor but are blocked by a protein
that rises up from the cancer cell like a shield.
The U.S. Food and Drug
Administration (FDA) approved a
new immunotherapy drug to treat
advanced melanoma, signaling
a paradigm shift in the way the
deadly skin cancer is treated.
UCLA led the international team
of researchers testing the drug,
pembrolizumab, in the largest
Phase 1 study ever conducted in
the history of oncology.
Pembrolizumab (Keytruda)
was tested on more than 600
patients who had melanoma
that had spread throughout
their bodies. Because so many
of the patients in the early
testing showed significant
long-lasting responses, the
study was continued, and
the FDA granted the drug
Pembrolizumab blocks the protein and breaks down
“breakthrough therapy” status,
the protective shield.
allowing it to be fast-tracked
for approval.
“This drug is a game-changer,
a very-significant advance in the
treatment of melanoma,” says
principal investigator Antoni
Ribas, MD (FEL ’98, ’01), PhD,
assistant director for clinical
programs in the UCLA Human
Gene Medicine Program. “For
patients who have not responded
After treatment with pembrolizumab, the immune
system is able to resume its attack by the white blood
to prior therapies, this drug now
cells, shrinking the tumors.
provides a very real chance to
Graphics: Courtesy of UCLA Jonsson Comprehensive Cancer Center
shrink their tumors and the hope
of a lasting response to treatment.”
Pembrolizumab, formerly known as MK-3475,
is an antibody that targets a protein called PD-1
that is expressed by immune cells. The protein
applies the brakes to the immune system, keeping
6 U MAGAZINE
its T cells from recognizing and attacking cancer
cells and hindering therapeutic attempts to fight
the disease. Pembrolizumab, in effect, cuts the
brake lines, freeing up the immune system to
attack the cancer.
“We have long believed that harnessing
the power of our own immune systems would
dramatically alter cancer treatment,” says Judith
Gasson, PhD, senior associate dean for research at
the David Geffen School of Medicine at UCLA
and director of UCLA’s Jonsson Comprehensive
Cancer Center. “Based upon work conducted over
the past two decades, we are beginning to see the
clinical benefits of this research in some of the
most-challenging cancers.”
Generally, about one-in-10 patients responded
to previous immunotherapy drugs. Some of those
who responded, however, exhibited long-lived
benefits, which sustained scientists’ interest
in the method as an effective mechanism to
fight cancer. The response and duration rates
for pembrolizumab were much greater than for
previous drugs, Dr. Ribas says. In the new study,
72 percent of patients responded to the drug —
their tumors shrank to some degree. Overall, 34
percent of patients showed an objective response,
meaning that their tumors shrank by more than
30 percent and did not re-grow.
Dr. Ribas said pembrolizumab has the potential
to be used to treat other cancers that the immune
system can recognize, including cancers of the
lung, bladder, head and neck.
To hear melanoma survivors speak about
their experiences with pembrolizumab,
go to: uclahealth.org/tomstutz and
uclahealth.org/kathythomas