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 Researchers are set to begin clinical trials using a more
comprehensive testing method that looks for all of the known genes
that may be active in a tumor.
The new method could guide patients to the right drug earlier,
potentially replacing current tests known as companion diagnostics
that only look for a specific biological trait or “biomarker.” The
presence of a biomarker can predict whether a new class of drugs
called targeted therapies will work on particular tumors.
Results of these broader tests could even be used to quickly
identify which patients might benefit from experimental drugs being
tested in clinical trials. U.S. health officials see it as the
future direction of cancer diagnostics.
"We really are moving away from this one drug, one biomarker, one
companion diagnostic," said Dr Richard Pazdur, the U.S. Food and
Drug Administration's oncology chief.
In advanced melanoma, for example, about half of patients' tumors
have a mutation in the BRAF gene. Roche makes a drug called Zelboraf
that blocks that pathway, at least for a time. To get Roche's drug,
patients need to be evaluated with an FDA-approved companion
diagnostic test. One of the tests is also made by Roche.
In many cases, the FDA requires single-biomarker companion
diagnostics as part of the drug approval process, but the broader
testing model opens the door to additional players in the
diagnostics space, including U.S.-based Foundation Medicine Inc and
Thermo Fisher’s Life Technologies.
In a trial starting later this month, for example, patients with
squamous cell carcinoma of the lung could be recommended for one of
five experimental treatments based on which genes are active.
Foundation Medicine's next-generation sequencing platform will be
used to screen some 6,000 lung cancer patients over five years.
The Lung Master Protocol trial, also known as Lung-MAP, will take
place in some 400 research centers. It is a public-private
partnership between the National Cancer Institute, Amgen Inc,
AstraZeneca Plc and its U.S.-based biotech arm MedImmune, Roche's
Genentech unit and Pfizer Inc.
A similar effort called the National Lung Matrix trial being
organized in Britain by AstraZeneca, Pfizer and Cancer Research UK
is set to start taking patients in July or August.[ID:nL6N0N63N5]
Pazdur said a conference this fall will also discuss plans for a
trial in metastatic breast cancer.
"This is a new paradigm in many, many ways," said Ellen Sigal,
chairperson and founder of Friends of Cancer Research, which is
organizing the U.S. lung cancer trial. "We're revolutionizing not
only the genetic testing but how patients get into a trial."
ONE TISSUE, MANY TESTS
Dr Mace Rothenberg, senior vice president of clinical development
for Pfizer's cancer business, said having a single test looking for
a single biological marker made sense when there were only a few
targeted cancer drugs, which exploit specific weaknesses in
patients’ tumors.
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"In the past 10 years, we've now identified many more potential
targets of drugs, and these molecules are involved in critical
functions of a cancer cell," he said. "Now it becomes very relevant
that we be able to go beyond that one tissue, one test to one
tissue, many tests."
In non-small cell lung cancer, for example, there are more than a
dozen different molecular abnormalities that are known to influence
tumor growth.
Dr Vince Miller, Foundation Medicine's chief medical officer, said
as more of the drugs win approval, doctors might need to run five to
eight tests, all from a tiny scrap of tumor.
"Tissue scarcity was becoming a very real issue," he said.
It's an issue that Dr. Tadd Lazarus, chief medical officer at
Germany's Qiagen NV, knows about personally.
Lazarus' father is battling his second round of lung cancer, and
biopsies must be done using a long needle, a process that produces
only a tiny tissue sample. "You get a fixed amount of tissue and you
have to maximize it," he said.
The German diagnostics company has three companion diagnostic tests
on the U.S. market, including one recently approved for Amgen's
colorectal cancer drug Vectibix.
Qiagen has also invested in a new testing platform from PrimeraDx, a
privately held Boston-area company. Under an expanded partnership
with Eli Lilly and Co, the companies plan to use the new platform to
analyze both DNA and RNA biomarkers, targeting multiple molecular
pathways active in common cancers.
Roche's Genentech is developing companion tests for about half of
the experimental medicines in its pipeline, and is evaluating tests
that can look at more than one target at a time, said spokeswoman
Holli Dickson.
(Reporting by Julie Steenhuysen; Editing by Michele Gershberg,
Martin Howell)
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