Push For Rapid Diagnostics, Protective Equipment Amid Flu Outbreak
Full article reprinted from "The Gray Sheet" - May 04, 2009
Find out how government health officials and industry are scrambling to identify and release diagnostics technology that can quickly identify patients stricken with the hybrid flu virus sweeping the globe, while demand for respirators and other personal protective equipment is rising.
Government health officials and industry are scrambling to identify and release diagnostics technology that can quickly identify patients stricken with the hybrid flu virus sweeping the globe, while demand for respirators and other personal protective equipment is rising.
There are many available rapid influenza assays, but most cannot differentiate the specific influenza A, H1N1 subtype strain blamed for, as of May 1, more than 300 illnesses worldwide and dozens of deaths (almost all in Mexico). So far, definitive identifycation of the strain is possible only with lab testing that takes at least several days to yield a result.
Officials say rapid testing tools are needed to get a better handle on the path of the disease, which as of May 1, was classified by the World Health Organization as a phase 5 pandemic alert (one phase shy of a bona fide global pandemic). CDC preparedness plans for pandemic flu also call for use of respirators and masks for persons treating flu patients, yet an Agency for Healthcare Research and Quality report issued last July questioned whether the U.S. had enough durable medical equipment and medical supplies to handle a pandemic flu outbreak ("1The Gray Sheet" July 28, 2008, p. 7).
Device trade association AdvaMed says it has been in contact with the U.S. Department of Homeland Security and public health agencies to "offer the medical technology industry's assistance" in combating the emerging threat.
FDA Employs Emergency Authorization
Meanwhile, FDA on April 27 authorized emergency use of the rRT-PCR Swine Flu Panel, which can produce results within four hours. The assay, developed by the Centers for Disease Control and Prevention, has not gone through the normal regulatory review process. FDA acted under a 2004 law allowing it to clear for marketing products that "may be effective" when an infectious disease emergency has been declared.
The rRT-PCR test runs on Applied Biosystems' 7500 Fast Dx system and can be performed on numerous samples at once. It amplifies viral genetic material from a nasal or nasopharyngeal swab.
A positive result indicates that the patient is presumptively infected with swine flu virus, but not the stage of infection. A negative result, however, does not by itself exclude the possibility of swine flu virus infection, FDA says.
The agency determined the test may be effective in analyzing samples from "individuals diagnosed with influenza A infections, whose virus subtypes cannot be identified by currently available tests."
The Centers for Disease Control and Prevention will distribute the test to public and other qualified laboratories that have the necessary equipment and personnel to run the test.
Companies Validate Tests Against H1N1 Strain
Meanwhile, some diagnostic makers are moving closer to approval and use of their tests to detect the H1N1 strain.
Molecular diagnostics firm Luminex said April 30 that it has confirmed the effectiveness of its xTAG RVP assay to help diagnose the swine flu strain. The firm verified through testing on confirmed swine flu-positive samples that the assay will correctly identify these samples as positive for influenza A in general, but negative for common seasonal flu strains of influenza A H1 and H3.
"xTAG RVP's ability to determine if a patient is carrying a normal, seasonal respiratory virus or an unknown H1 flu A virus can be a critical first line of defense in separating standard respiratory infections from swine flu cases," CEO Patrick Balthrop said.
Luminex says the xTAG system is the only FDA-cleared test that can distinguish between different subtypes of the flu virus.
CombiMatrix CEO Amit Kumar claims that the firm's Influenza A Detection Microarray, which uses a semiconductor-based DNA chip,can identify the new strain of flu, provide information on novel strains of flu produced by rapid mutation and also has the capacity to determine which strains are resistant, and which are not.
The test can use samples taken from nasal swabs of patients suspected to have swine flu, and provide a positive or negative answer within four to five hours, Kumar said. The CombiMatrix array is a research-use-only test.
"But if this swine flu outbreak turns into something dramatic, we're ready to provide it," Kumar said. He added that the firm has been "talking with the Ministry of Health in Mexico" about potentially providing the test, "and we are submitting our data to the CDC."
Test maker Qiagen also says that two of its tests can be used to screen for the new strain: the artus Influenza LC RT PCR Kit and the Resplex II 2.0 Kit. Thomas Grewing, Qiagen senior director for R&D, said that the firm has compared the swine virus sequence with Qiagen's assays, and they match 100% for the artus kit, and almost 100% for the Resplex kit. The firm says it is working closely with reference institutions to have both assays further re-validated and optimized, based on clinical samples.
Another system being put to use in response to the outbreak, according to several reports, is Abbott/Ibis Biosciences' research-use-only T5000 biosensor (2"The Gray Sheet" Dec. 22, 2008, p. 17).
Point-Of-Care Tests Sought
While each of these tests offers relatively rapid results, they involve somewhat complex molecular diagnostics and cannot be used by health care workers at the point of care. Scientists are trying to develop such a point-of-care test right now, according to Bruce Carlson of market research firm Kalorama Information, which is studying the impact of the swine flu outbreak on the diagnostics industry.
On April 29, Utah-based DxNA announced that it was putting together a portable detection assay for the swine flu strain that it hopes to have ready for evaluation in one to two weeks. The assay would be used on the firm's GeneSTAT platform, which weighs less than 10 pounds and provides results in about 45 minutes. It is meant for use at the site of an outbreak.
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