FDA Approves Merck's New-Wave Cancer
Drug
New
Treatment, Which Costs $150,000 a Year, Is Aimed at Bolstering the Body's
Immune System
U.S.
regulators on Thursday approved a new kind of cancer drug from Merck & Co.
that is designed to unleash the body's immune system against tumors. The drug is
part of a long-anticipated wave of medicines that could transform cancer
treatment and forge a large new market for pharmaceutical companies.
The
Food and Drug Administration cleared the drug, pembrolizumab, for the treatment
of a deadly form of skin cancer, melanoma. The approval followed a swift review
of data from a relatively early-stage human trial—an unusual move reflecting
the medical community's keen interest in pembrolizumab. Merck plans to sell the
drug under the brand name Keytruda.
The
drug comes with a steep price: Merck said the cost to payers for many patients
will be $12,500 per patient monthly, or $150,000 for a year's worth of
treatment.
Keytruda,
an infused drug, is a new type of immunotherapy, a category of treatments that
harness the immune system to fight cancer. It was approved for people who've
failed to respond adequately to Yervoy, a Bristol-Myers Squibb Co. immunotherapy
that works in a different fashion, and certain other drugs.
Pembrolizumab
is the first so-called PD-1 inhibitor to hit the U.S. market. The drugs block a
protein called programmed death receptor 1, or PD-1, which acts as a brake on
certain immune-system cells to prevent them from attacking healthy tissue.
Cancer cells can escape destruction by latching onto PD-1; PD-1 inhibitors
block this interaction at the site of the tumor, releasing the immune system
brake and allowing it to destroy the cancer. Yervoy also lifts a brake on the
immune system, but does so earlier in the immune-cell activation process, which
researchers say may cause more collateral destruction of normal tissue than
with PD-1 blockers.
Pembrolizumab
and other PD-1-targeting drugs—including those developed by Bristol-Myers and
Roche Holding AG —have generated
excitement among doctors because they appear to induce relatively high rates of
tumor shrinkage and prolong average survival beyond historical norms in
clinical studies. Researchers say the side effects associated with the drugs
appear to be manageable.
"PD-1
is truly a game-changer. It's active in a way that other drugs are not,"
said Lynn Schuchter, a medical oncologist who heads the melanoma program at the
Abramson Cancer Center of the University of Pennsylvania and has assisted in
clinical trials of the Merck drug. "And what's been interesting is the
activity of PD-1 beyond melanoma. It looks to be active in bladder and renal
and lung cancer. So this is bigger than melanoma."
Some
analysts believe total annual sales of cancer immunotherapies could reach about
$32 billion by 2025, if more drugs make it to market to treat a range of
cancers. Leerink Swann estimates Merck's new drug alone could generate annual
sales of more than $6 billion by then.
A
competing PD-1 inhibitor, nivolumab, hit the market in Japan this month, at a
price of $143,000 for a year's worth of treatment for the average Japanese
patient. The drug, from Bristol-Myers and Ono Pharmaceutical Co, is expected to
be reviewed by U.S. regulators in coming months. The high price tags could fuel
more debate about the affordability of new drugs.
Until
a few years ago, most patients with advanced melanoma could be expected to live
less than a year. Bristol's Yervoy and other drugs targeting cancer-causing
genetic mutations have begun to improve the outlook. Now, Merck's pembrolizumab
and similar drugs are expected to provide further advances. About 76,000
Americans are diagnosed with melanoma each year, and about 9,700 die of the
disease annually, according to the American Cancer Society
This
summer, researchers said about 69% of advanced melanoma patients receiving
pembrolizumab in a clinical study were still alive after one year of treatment
and 62% were alive at 18 months. Overall, about 34% of patients experienced
tumor shrinkage of 30% or more. About 12% of patients experienced a significant
adverse event such as fatigue, while 4% discontinued treatment due to an
adverse event. The trial didn't have a comparator arm.
"Now
I have patients coming back in significant numbers who are effectively treated
with this agent, and the response is durable," said Antoni Ribas, a
melanoma specialist and professor of medicine at UCLA's David Geffen School of
Medicine, who served as lead investigator of the study.
Still,
the Merck drug and other immunotherapies don't work in every patient and can't
be considered a broad-based cure. Researchers are exploring biological markers
such as the presence of certain proteins on cancer cells that may help doctors
select patients most likely to benefit from a particular drug—and those less
likely to benefit. Richard Pazdur, director of the FDA's office of hematology
and oncology products, said finding such predictors is "an area that cries
out for further attention."
Merck
began testing the drug in humans in 2011 in what is known as a phase 1 study.
Such studies are typically conducted in a small group of patients to test
whether a drug is safe. Usually, two additional phases of studies—with larger patient
populations—are needed to demonstrate a drug's efficacy and safety before the
FDA will consider approving it, but sometimes the agency approves cancer drugs
based on early- to midstage trials.
Dr.
Ribas said he started to notice positive results relatively soon after he began
overseeing pembrolizumab's testing in melanoma patients. The phase 1 study also
included patients with other tumor types such as lung cancer. Merck made the
unusual decision to expand and continue the phase 1 study, which eventually
grew to more than 1,100 patients of various tumor types, believed to the biggest
phase 1 cancer study ever.
One
study participant, 59-year-old Kathleen Thomas of Redondo Beach, Calif., said
she felt like she'd been given a "death sentence" when she was
diagnosed with advanced melanoma in April 2011.
Her
disease progressed after treatment with surgeries and drugs including Yervoy.
She lost weight and strength, forcing her to use a wheelchair. Within months of
joining the pembrolizumab trial in late 2012, Ms. Thomas said she began to feel
better, regaining weight and using the wheelchair less often. Imaging scans
have shown that her tumors have either shrunk, disappeared or remained stable,
she said.
Patient
interest in the Merck drug and other immunotherapies has given rise to petition
drives and social-media campaigns seeking access to the drugs before regulators
had approved them for sale. Such demand has fueled legislation in some states
that gives terminally ill patients a "right to try" certain experimental
drugs without having to go through an FDA program for early access, if a drug's
manufacturer is willing. Merck started an early access program for
pembrolizumab in March, but restricted it to patients whose disease had
progressed after treatment with Yervoy and, if applicable, a drug targeting a genetic
mutation known as BRAF.
After
starting human testing in 2011, Merck raced to close the gap with rival
Bristol-Myers, which introduced Yervoy in 2011 and was ahead on testing its own
PD-1 inhibitor, nivolumab.
Merck
got a boost in early 2013 when the FDA deemed pembrolizumab a
"breakthrough therapy," a new designation that made it eligible for a
speedier review and extra attention from top FDA officials. Last year, Merck's
new R&D chief, Roger Perlmutter, terminated several other R&D projects
and shifted resources to pembrolizumab and other promising programs.
Merck
Chief Executive Kenneth C. Frazier, a company veteran since 1992, called
pembrolizumab "one of the most exciting programs I've been associated with
since I've been at Merck." He likened it to the company's introduction of
anti-HIV medicine Crixivan in 1996, among the early protease inhibitors that
helped reduce the risk of death from AIDS.
Merck
said in late July it expects to have enough supply of pembrolizumab to be ready
for a market launch, including meeting potential demand for
"off-label" uses of the drug, which would treat a cancer type not
included in the initial FDA-approved prescribing label.
More
new immunotherapies could be on the horizon. Bristol-Myers expects to file by
Sept. 30 for FDA approval of nivolumab as a melanoma treatment, and by year-end
for approval of its use to treat lung cancer.
Bristol's
drug also has generated positive clinical results, and some analysts believe
the company will eventually dominate the immunotherapy market. Researchers said
this summer that melanoma patients receiving a combination of Yervoy and
nivolumab in a clinical trial had a median overall survival of 40 months,
though many experienced significant adverse events such as the bowel disorder
colitis.
