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USDS Concept Raises Questions<br />

national lab service, continued from page 1<br />

and readouts. “USDS would be a way to do<br />

premarket testing of diagnostics and would<br />

generate standardized data that would improve<br />

the evaluation of diagnostic tests <strong>for</strong><br />

approval by the FDA,” explained Maryellen<br />

de Mars, C-Path’s Director, <strong>Clinical</strong> Biomarkers.<br />

“The idea is to provide standardized<br />

samples and procedures. It’s quality<br />

assurance, in a way.” According to the organization’s<br />

Web site, C-Path is an independent<br />

nonprofit research and education<br />

institute that helps FDA’s Critical Path Initiative<br />

by spurring “collaborations among<br />

the FDA, academia, and regulated business<br />

to improve the process of developing new<br />

medical products, making them faster, safer,<br />

and smarter” (See Box).<br />

<strong>Laboratory</strong> directors familiar with the<br />

ef<strong>for</strong>t believe it has the potential to benefit<br />

manufacturers, clinical labs, and patients,<br />

but say that the concept of a national diagnostic<br />

testing service raises some serious<br />

questions. How will C-Path fund what<br />

promises to be a huge and costly project and<br />

still maintain the lab’s independence? Will<br />

the existence of the USDS increase pressure<br />

on FDA to regulate lab-developed tests?<br />

And will USDS compete with academic<br />

labs that currently partner with companies<br />

on validation studies?<br />

Fulfilling a Need<br />

Right now, FDA submissions often raise<br />

questions about variations in sampling<br />

methodologies, assay procedures, and how<br />

well clinical data correlates to particular<br />

samples, a process known as clinical annotation,<br />

noted Fred R. Hirsch, MD, PhD,<br />

Professor of Medicine and Pathology at<br />

University of Colorado Cancer Center in<br />

Denver. Differences in how individual labs<br />

handle these processes sometimes make<br />

FDA, labs, and physicians question that<br />

data. “When there is variation in procedures,<br />

it’s difficult to interpret the data. You<br />

want to be sure that results reflect true biological<br />

variation and not just variation in<br />

methodology,” he explained.<br />

Standardization of cancer biomarker<br />

assays could be an aid to FDA, according<br />

to AACC Past President Gary Myers, PhD,<br />

Chief of the <strong>Clinical</strong> <strong>Laboratory</strong> Branch<br />

in CDC’s Division of <strong>Laboratory</strong> Sciences,<br />

which has helped create important standards<br />

<strong>for</strong> cholesterol and HbA1c assays.<br />

That’s because the FDA must often evaluate<br />

data presented in different <strong>for</strong>mats. “Having<br />

a lab where standard sample sets are<br />

used to devaluate diagnostic products, and<br />

evaluation results all follow common, standardized<br />

<strong>for</strong>mats would make it easier <strong>for</strong><br />

FDA to review and evaluate product submissions.<br />

It could compare apples to apples<br />

and oranges to oranges,” Myers explained.<br />

A Menu of Useful Services<br />

An executive summary of a proposal describing<br />

USDS lists several benefits that<br />

C-Path hopes to offer diagnostics companies.<br />

These include standardizing the validation<br />

process, a ready supply of standardized<br />

samples, data that compare potential<br />

products to those of competition, and neutral<br />

third-party evaluation. The summary<br />

goes on to provide details of the proposed<br />

repository, which would be “a collection of<br />

highly qualified, annotated clinical sam-<br />

ples.” The repository would include tissues<br />

and fluids with confirmed diagnoses, clinical<br />

outcomes, and controls. USDS would<br />

be subject to CLIA, CAP, and International<br />

Organization of Standardization requirements,<br />

the summary adds.<br />

De Mars emphasized that C-Path is<br />

in the early stages of planning <strong>for</strong> USDS.<br />

“We’re in the process of compiling an advisory<br />

board <strong>for</strong> the project to define scope<br />

and strategy. But there’s general support<br />

and excitement throughout the industry<br />

about creating standards in this area.”<br />

A key FDA official confirmed that discussions<br />

about the project are still preliminary<br />

and that C-Path is “working out the<br />

bugs” in its concept. But Steven Gutman,<br />

MD, Director of the Office of In Vitro Device<br />

Evaluation and Safety, also emphasized<br />

that FDA’s role is minimal at this point.<br />

While the agency supports the concept of<br />

a national diagnostic service lab, C-Path<br />

initiated the current proposal <strong>for</strong> how the<br />

lab would operate. FDA has given C-Path<br />

advice but no money so far. “FDA’s position<br />

on USDS, as with many C-Path activities,<br />

is that we offer our perspective and maybe<br />

funding <strong>for</strong> small studies, and <strong>for</strong>m partnerships,”<br />

Gutman explained.<br />

While he minimizes FDA’s role in<br />

USDS, Gutman says its planned contribution<br />

to the development of new assays<br />

would be valuable. “It will improve the<br />

quality of the science in submissions. With<br />

or without regulation, if you can improve<br />

science, that’s always a plus,” he said. Any<br />

type of assay that isn’t well-standardized<br />

might benefit, he added, noting that USDS<br />

might be particularly helpful in preparing<br />

proteomic assays <strong>for</strong> FDA submission. “We<br />

haven’t cleared one yet. There’s a paucity<br />

of methods, materials, and standards <strong>for</strong><br />

proteomics. If the new enterprise improved<br />

standardization <strong>for</strong> these assays, it could really<br />

move the field <strong>for</strong>ward.”<br />

The Pilot: A Focus on EGFR<br />

C-Path expects that an NCI clinical study,<br />

now in its early stages, will help establish a<br />

USDS pilot program by determining the<br />

infrastructure necessary to provide planned<br />

services. The phase III trial will screen almost<br />

1,200 non-small cell lung cancer patients<br />

to determine EGFR copy number<br />

by FISH. The trial will retrospectively determine<br />

the presence of EGFR mutations<br />

by sequencing and protein expression by<br />

immunohistochemistry (CLN, February<br />

2008). Afterward, researchers will randomize<br />

patients, who have already had first-line<br />

therapy, to receive either the tyrosine kinase<br />

inhibitor (TKI) erlotinib or chemotherapy<br />

with pemetrexate. The trial’s primary goal<br />

is to determine the most suitable EGFR<br />

biomarker and to identify the patients who<br />

benefit most from TKI inhibitors, according<br />

to Janet Dancey, MD, Associate Chief of<br />

the Investigational Drug Branch in NCI’s<br />

Cancer Therapy Evaluation Program. She<br />

is coordinating the trial.<br />

De Mars identified other goals that are<br />

more directly related to USDS’s mission.<br />

The study’s first phase will not only determine<br />

the best method <strong>for</strong> measuring EGFR,<br />

but will also help establish a standardized<br />

process <strong>for</strong> FDA to validate and assess predictive<br />

biomarkers. Future phases could<br />

also help diagnostic companies access valu-<br />

c-path initiative Targets<br />

preclinical safety biomarkers<br />

another C-path project aims to establish new ways of determining<br />

experimental drugs’ human toxicity be<strong>for</strong>e they are tested in patients.<br />

launched in March 2006, the predictive safety testing Consortium<br />

plans to help fda and its european equivalent, the european<br />

Medicine evaluation agency (eMea), qualify new biomarkers of<br />

human safety.<br />

the consortium’s director, william Mattes, phd, says there is a major<br />

need <strong>for</strong> new biomarkers of toxicity. <strong>for</strong> example, some preclinical<br />

tests of toxicity are as much as 60 years old, and in certain cases,<br />

related data comes from anecdotal reports, not actual scientific<br />

scrutiny.<br />

through their membership in the consortium, 16 pharmaceutical<br />

companies are now sharing their internally developed preclinical<br />

safety biomarkers and testing each other’s methods to see if they<br />

are reproducible. the consortium’s ultimate goal is to present the<br />

companies’ data to the fda and eMea, which will deem some of<br />

the markers the consortium examines as qualified <strong>for</strong> use in drug<br />

development, according to Mattes. last year, the consortium submitted<br />

seven urinary biomarkers of kidney injury, and in May 2008, the<br />

fda and eMea confirmed their joint review and acceptance of these<br />

tests.<br />

C-path plans to submit data on more potential biomarkers. other<br />

consortium projects are focused on markers of harm to the liver,<br />

muscle, and vascular system. another is examining focuses on carcinogenicity<br />

in rodents.<br />

the consortium hopes that the companies’ shared experience<br />

with the safety biomarkers will go a long way toward establishing<br />

consensus about them. “we want to develop new, better, and more<br />

sensitive and specific tools <strong>for</strong> determining safety and get broad<br />

industry, regulatory, and scientific agreement about their safe use,”<br />

explained elizabeth walker, phd, the consortium’s assistant director.<br />

able clinical samples <strong>for</strong> developing new<br />

biomarkers and technologies, cross-validate<br />

new tests, and support a standardized process<br />

<strong>for</strong> evaluation of diagnostics by FDA.<br />

C-Path has proposals from a total of 14 diagnostics<br />

companies with technologies that<br />

measure EGFR or other potential targets.<br />

Future phases of the trial might use these<br />

technologies, with the goal of identifying<br />

new predictive or prognostic markers.<br />

Colorado Cancer Center’s Hirsch is coordinating<br />

the biomarker studies <strong>for</strong> the trial<br />

on behalf of Southwest Oncology Group,<br />

which has headquarters in Ann Arbor,<br />

Mich., and researchers at about 550 institutions.<br />

He described the study as a prospective<br />

biomarker-driven trial that is unique in<br />

its scope. While various groups have studied<br />

outcomes of patients whose treatment was<br />

based on assessment of their EGFR status,<br />

this trial is the first to join a large number of<br />

oncology cooperatives, NCI, and diagnostics<br />

companies, he explained. “The trial is<br />

also a demonstration that prospective biomarkers<br />

can be validated in a collaborative<br />

way among all of these partners. They have<br />

spent a lot of time building up a complex<br />

infrastructure.”<br />

At the end of the study’s first phase, researchers<br />

hope to have 970 patients’ blood<br />

and tumor samples, all collected according<br />

to standardized methods <strong>for</strong> analysis of mutations,<br />

gene copy number, and protein expression.<br />

Meanwhile, the data will be based<br />

on standard mutation, gene copy number,<br />

and mutation methods. “While this type<br />

of standardization exists in individual labs<br />

and centers, we will have several centers and<br />

cooperatives all using a standardized methodology,”<br />

Hirsch noted.<br />

The samples will be both precious and<br />

well-suited <strong>for</strong> tests of other markers, ac-<br />

cording to Dancey. Specifically, she noted<br />

that each of the samples will be linked to<br />

outcomes data <strong>for</strong> a certain therapy, so in<br />

the future, researchers investigating toxicity<br />

or survival will be able to trace particular<br />

data back to specific samples.<br />

A similar but smaller study has already<br />

dealt with many of the questions the NCI<br />

trial aims to answer, noted Marc Ladanyi,<br />

MD, Chief of the Molecular Diagnostic Service<br />

and Attending Pathologist at Memorial<br />

Sloan-Kettering Cancer Center. Led by<br />

CliniCal laboratory news JuLy 2008 3

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