February 3, 2014 Division of Dockets Management (HFA–305) Food and Drug Administration

February 3, 2014
Division of Dockets Management (HFA–305)
Food and Drug Administration
5630 Fishers Lane, Rm. 1061
Rockville, MD 20852
ATTN: Leslie Kux, Assistant Commissioner for Policy
Ref: [Docket No. FDA–2013–D–1213]; Draft Guidance for Industry: Use of Donor Screening Tests to
Test Donors of Human Cells, Tissues, and Cellular and Tissue-Based Products (HCT/Ps) for Infection
with Treponema pallidum (Syphilis); 78 Federal Register 214; November 5, 2013.
Dear Assistant Commissioner Kux:
On behalf of the 85 U.S. member eye bank organizations, the Eye Bank Association of America
[hereinafter referred to as the “EBAA” or the “Association”] appreciates the opportunity to comment on
the Food and Drug Administration’s Draft Guidance for Industry that recommends the use of FDAlicensed, approved or cleared donor screening tests for testing donors of HCT/Ps for infection with
Treponema pallidum (Syphilis).
Our U.S. member organizations provide close to 100% of all corneal tissue used for transplantation in
the U.S. All EBAA eye bank members are 501(c) (3) organizations whose mission is to procure and
provide donated human eye tissue for sight restoring transplantation procedures. The Association
strives to ensure the superior quality of banked human eye tissue through the adoption and
implementation of stringent medical standards, which are scientifically based, and specific to ocular
EBAA Background
The EBAA is the world’s oldest transplantation association, established in 1961 by the American
Academy of Ophthalmology (AAO). The EBAA first established medical standards and an accreditation
program for inspection of eye banking organizations in 1980, and certification of technicians followed in
the late 1980s. The Association’s standards and procedures have been used as a model for adaptation
by other organizations in the United States, and other countries. They are reviewed and revised twice a
year by a board of renowned corneal surgeons and certified technicians with expertise and extensive
experience in eye banking and then formally considered by the AAO, which has endorsed them each
year since 1981. The EBAA standards representing “best practices” in eye banking, are based on science
specific to ocular tissue, and enjoy widespread recognition and acceptance. The Medical Advisory Board
1015 18TH STREET NW, SUITE 1010 | WASHINGTON DC 20036 | 202-775-4999 | RESTORESIGHT.ORG
is responsible for promulgating EBAA medical standards, and a U.S. Food and Drug Administration (FDA)
representative sits on the board.
The EBAA Accreditation Board, also established in 1980, conducts inspections of eye bank members on a
regular three-year cycle or more often, as necessary. Eye banks which are accredited by the EBAA,
follow EBAA medical standards, and employ EBAA procedures which closely parallel and often exceed
those of the FDA Good Tissue Practice regulations.
The eye banking and corneal transplant community expects that any guidelines or regulations are
consistent, reasonable and evidence-based. We have read and researched the draft guidance and have
some concerns with the proposed requirement to utilize only FDA-licensed, approved, or cleared donor
treponemal screening tests.
Based on the comments and supporting rationales that we make in response to the draft guidance, we
offer the following recommendations:
Stay the publication of the final guidance until research demonstrates that treponema-specific
antibody tests for the diagnosis of syphilis in donors of ocular tissue and other HCT/Ps is
proven as scientifically warranted.
Continue to allow FDA-cleared diagnostic serological tests for evidence of infection with T.
pallidum for use as HCT/P donor screening tests.
Perform parallel studies to determine if the traditional RPR screening test or the treponemaspecific screening test is likely to result in more false-positive results in a donor population
with a low prevalence of syphilis.
The FDA and Health Resources and Services Administration (HRSA) outline appropriate policy
consideration for shared organ and tissue donors.
The EBAA offers these comments in the spirit of cooperation and collegiality, and we look forward to
working with the FDA and our other transplant partners to ensure the safety of corneas and other tissue
provided for transplant. Based on our current recommendations, the EBAA cannot support the FDA’s
recommendation to test all HCT/P donors using appropriate FDA-licensed, approved, or cleared donor
screening tests for T. pallidum.
We take this position for the following reasons:
1) Use of treponema-specific donor screening tests may identify a higher number of patients with falsely
reactive results than traditional non-treponema diagnostic tests and cannot differentiate between active
disease and previous infection.
2) The Centers for Disease Control and Prevention (CDC) continues to recommend traditional screening
using a nontreponemal test followed by testing of reactive sera with a treponemal test.
3) Because parallel studies have not been done, it is unclear if the traditional RPR screening test or the
treponema-specific screening test is likely to result in more false-positive results in a HCT/P donor
4) FDA did not coordinate its proposal for testing requirements with HRSA, OPTN, and UNOS or consider
the policy implications between organ and tissue donation and transplantation.
5) There is no evidence in the literature, either experimental or clinical, to suggest the transmission of
syphilis via corneal transplantation.
FDA-cleared donor screening tests for T. pallidum may identify a higher number of patients with
falsely reactive results than traditional nontreponemal assays, leading to the loss of corneal donors.
For years, the traditional algorithm used for the diagnosis of syphilis has called for screening with a
nontreponemal assay, either the venereal disease research laboratory (VDRL) test or, more commonly,
the RPR test that detects anticardiolipin antibodies. Nontreponemal tests are highly sensitive, but since
these antibodies are not specific for syphilis, they may be falsely positive in circumstances such as
autoimmune disease, IV drug use, pregnancy, acute viral infections, or recent immunizations. Therefore,
a positive reactive nontreponemal assay (RPR or VDRL screen) must be confirmed with an assay that
detects antibodies produced against T. pallidum. The FDA-cleared confirmatory test for syphilis is the
fluorescent treponemal antibody absorption (FTA ABS) test. This allows for screening with a relatively
inexpensive test and increased the positive predictive value (PPV) of a reactive result in the treponemal
test to greater than 99%.1
Recently, treponema-specific assays have been developed and have been cleared by the FDA as donor
screening tests for T. pallidum. Some clinical laboratories and blood banks have begun to screen samples
using treponemal enzyme immunoassays (EIA). This strategy will identify both persons with previous
treatment and persons with untreated or incompletely treated syphilis. False-positive results can occur,
particularly among populations with a low prevalence of syphilis.
Of the FDA-cleared donor screening tests for syphilis, the CAPTIATM Syphilis (T. pallidum)-G enzyme
immunoassay (EIA) is most often available by commercial laboratories who provide cadaveric panels for
donor testing. Unfortunately, not all commercial laboratories utilized by eye banks currently offer this
test. One of the four FDA-cleared screening tests for syphilis, the ASI TPHA test is no longer available in
the United States.
The use of treponemal immunoassays to screen for syphilis eliminates biological false positives due to
the presence of anticardiolipin antibodies from other diseases. A number of studies have shown that
immunoassays have fewer false positives than nontreponemal assays. The sensitivity and specificity of
the CAPTIA Syphilis-G EIA compared to standard syphilis tests were reported by Hooper and colleagues
to be 100% and 99.9%, respectively, and by Reisner et al to be 100% and 99.8%, respectively.2,3 Head-tohead comparisons showed specificities of 98% to 99% for immunoassays and consistently slightly lower
specificities of 98% to 99% for RPR.4
Excellent specificity notwithstanding, any test will have a poor positive predictive value when performed
on populations with extremely low disease prevalence. Treponemal immunoassays do not distinguish
between remote, treated infection and current, active infection. Because the CAPTIA only detects IgG
antibody, a reactive CAPTIA test would rule-out any potential HCT/P donor that has been previously
treated for syphilis. Furthermore, treponemal antibody tests suffer from cross-reactivity with other
spirochete infections and non-syphilis Treponemal infections.
For this reason, reverse algorithm guidelines recommend that all specimens positive by a treponemal
immunoassay also be tested by a standard nontreponemal assay (i.e., RPR) with titer to diagnose active
disease and monitor response to treatment. If the nontreponemal test is negative, then a different
treponemal test should be performed to confirm the results of the initial test. If a second treponemal
test is positive, persons with a history of previous treatment will require no further management unless
sexual history suggests likelihood of re-exposure. Those without a history of treatment for syphilis
should be offered treatment. Unless history or physical examination suggests a recent infection,
previously untreated persons should be treated for late latent syphilis.
In a direct comparison of reverse and traditional algorithms, Binnicker et al. reported a higher falsereactivity rate by reverse screening.5 However, all false-reactive IgG results were negative by RPR and
TPPA and the overall results would have been interpreted as negative at the completion of the testing
algorithm. These false-reactive IgG results would unnecessarily eliminate potential tissue donors.
A significant advantage of immunoassays is that they can be automated, significantly reducing labor and
increasing sample throughput compared to other syphilis tests. While this may be useful for highvolume laboratories and screening blood donors, traditional screening is more appropriate for lowvolume clinical laboratories and eye banks.
Nontreponemal assays (such as RPR) are relatively easy to perform, inexpensive, provides a more rapid
screening method when low numbers of samples are tested, and do not require expensive
instrumentation. Because the results are quantitative, they can be used to follow response to therapy
and to detect reinfections.
The EBAA requests that FDA continue to allow HCT/P establishments to utilize FDA-cleared
nontreponemal diagnostic assays, which provide sufficient evidence of active, clinical disease and allow
for additional confirmatory testing with treponemal tests to differentiate between true- and falsepositives.
The Centers for Disease Control and Prevention (CDC) recommends screening with a nontreponemal
CDC recommends syphilis serologic screening with a nontreponemal test, such as the rapid plasma
reagin (RPR) or Venereal Disease Research Laboratory (VDRL) test, to identify persons with possible
untreated infection; this screening is followed by confirmation using one of several treponemal tests.6
This recommendation is based on years of experience with the traditional testing algorithm, as well as a
number of studies suggesting that the results of RPR screening may show a higher degree of correlation
with disease activity than the reverse testing algorithm. This is due to the fact that treponemal tests
(e.g., EIA) are not able to distinguish between active disease and past, successfully treated, syphilis. In
contrast, nontreponemal tests, such as RPR, generally become negative following treatment and
therefore, can be used to monitor a patient’s response to therapy. Nontreponemal test titers usually
correlate with disease activity, and the results are reported quantitatively.
CDC continues to recommend traditional screening using a nontreponemal test followed by testing of
reactive sera with a treponemal test. When reverse sequence screening is used, CDC recommends
reflexively testing all sera that produce reactive EIA/CIA results with a quantitative nontreponemal test,
and reflexively testing sera with discordant results (i.e., reactive EIA/CIA and nonreactive RPR/VDRL test)
with a confirmatory Treponema pallidum particle agglutination assay (TP-PA); all test results should be
reported promptly and concurrently to the clinician and public health department.
Use of treponemal-specific screening tests may increase the rate of donors with screen-reactive, and
potentially falsely reactive, results which will exclude donors with past infections.
In 2011, the CDC published a landmark study in which syphilis serology results (n = 140,176) from five
clinical laboratories using reverse screening between 2006 and 2010 were reviewed.7 Three of these
laboratories served areas with a low incidence of syphilis, while the remaining two labs served a highprevalence population. Among the 140,176 samples screened by EIA or chemiluminescence
immunoassays (CLIA), 4,834 (3.4%) were reactive by the treponemal test. Of the 4,834 EIA/CLIA-reactive
samples, 2,734 (56.7%) were nonreactive by RPR, of which 866 (31.6%) were also nonreactive by a
second treponemal test (e.g., TPPA or FTAABS), suggesting falsely reactive EIA/CLIA results. Interestingly,
the percentage of discordant (EIA/CLIA-reactive, RPR nonreactive) serum samples was higher in the lowprevalence population than in the high-prevalence population (60.6 versus 50.6%). It was also observed
that the percentage of discordant serum samples testing nonreactive by TPPA or FTA-ABS was greater in
the low-prevalence population than in the high prevalence group (40.8% versus 14.4%).
In summary, the data indicate that among patients with reactive EIA/CIA results, 56.7% had nonreactive
nontreponemal test results and among these discordant sera, 12.2%-60.0% were nonreactive with a
second treponemal test.7 This suggests that reverse screening may identify a higher number of patients
with falsely reactive results than the traditional testing algorithm, especially when used in areas with
low disease prevalence. We conclude that up to 60% of donors who test positive for the CAPTIA would
be disqualified unnecessarily if the new FDA guidelines regarding syphilis screening go into effect as
proposed. This would result in an unnecessary reduction of the donor pool of 1.93% due to false positive
test results.
HCT/P establishments must test a specimen from the donor of cells or tissue, whether viable or
nonviable, for evidence of infection due to relevant communicable disease agents, including T. pallidum
(1271.85(a)(5)). A tissue donor whose specimen tests positive or reactive on a treponemal screening test
is not eligible.
Current FDA Guidance for Industry: Eligibility Determination for Donors of Human Cells, Tissues, and
Cellular and Tissue-based Products requires tissue establishments to determine potential donor to be
ineligible who have been treated for or had syphilis within the preceding 12 months. Further, this
guidance states: “We do not recommend deferral of donors if evidence is presented that the treatment
occurred more than 12 months ago and was successful.” And yet, the testing available would require
that those donors are ruled out, even if the treatment was more than 12 months ago.
Blood donors may be re-entered into the donor pool if another, different treponemal screening test
result is negative or a non-treponemal screening test is nonreactive and the donor provides
documentation of successful treatment for syphilis completed at least 2 months before their next blood
donation. This is according to the March 2013 Draft Guidance for Industry: Recommendations for
Screening, Testing, and Management of Blood Donors and Blood and Blood Components Based on
Screening Tests for Syphilis. Cornea donation is a one-time gift and blood samples from an eye donor
cannot be re-tested after the time of referral.
Parallel studies are needed to determine if the traditional RPR screening test or the treponemaspecific screening test is likely to result in more false-positive results in a donor population with a low
prevalence of syphilis.
EBAA recently conducted a survey of member eye banks in January 2014 regarding their donor testing
for syphilis. Ninety percent (55/61) of U.S. banks who responded are utilizing a diagnostic
nontreponemal (RPR) screening test for syphilis, with a confirmatory fluorescent treponemal antibody
absorption (FTA-ABS) test. These 55 eye banks represent 77% of the corneal donor pool for U.S. eye
The six (6) U.S. banks who reported using an FDA-cleared treponemal donor screening test utilize the
CAPTIATM Syphilis (T. pallidum)-G enzyme immunoassay (EIA). Additionally, four Canadian banks are
utilizing the CAPTIATM Syphilis-G test as part of their donor screening panel. These banks did not report a
noticeable increase in donor rule outs and one bank reported that it was more cost effective to do the
treponemal test, since there would be fewer false positives and less tissue lost due to time waiting for
the confirmatory testing when a non-treponemal test is positive. It should be noted that these six banks
are not our larger volume eye banks and only represent 4% of the corneal donor pool. Therefore
statistical differences would not be noticed.
Since 1962, member banks have provided annual donation and transplantation statistics to EBAA, which
reflects the eye banking activity for the previous year. The 2012 Eye Banking Statistical Report is a
compilation of information provided to the EBAA by all U.S. member eye banks and reflects an
essentially complete picture of eye banking activity in the United States.
In 2012, 348 of the 103,774 (0.3%) of the corneas intended for surgery were determined to be ineligible
for transplant due to positive syphilis testing. This was using the 2007 Donor Eligibility guidance which
allows FDA-cleared diagnostic serological tests for use in donor screening for syphilis. Delaying
finalization of this guidance will allow the EBAA, as well as the testing laboratories, to perform these
needed studies to determine if treponemal specific screening tests will increase or decrease the number
of donors who are ruled out.
In February 2013, CDC published two analyses that provide an in-depth look at the severe human and
economic burden of sexually transmitted infections (STIs) in the United States. CDC’s new estimates
were developed using the best available data. The estimates are based on national surveys, nationally
notifiable disease case reports, and data from special projects. The primary data source used to estimate
the number of most prevalent infections was the National Health and Nutrition Examination Survey
(NHANES), a nationally representative sample of the civilian, non-institutionalized population in the
United States that includes testing for STIs. The estimated number of new and existing (total) syphilis
infections was 117,000.8
The proposed syphilis testing guidelines show a lack of coordination of policy implications between
organ and tissue donation and transplantation.
Approximately 1/3 of organ donors are also tissue donors.9 If tissue donors must be screened using
treponemal-specific screening tests for syphilis and organ donors are not, when a shared donor’s EIA
test is positive, and that report is received by an organ procurement organization (OPO) or transplant
center, the organs may be rejected for transplant. Furthermore, if the organs have already been
transplanted, the transplant surgeons may begin unnecessary treatment for syphilis, based on a
screening test with a known high false positive rate. These discordant test results do not occur with the
traditional testing algorithm because only nontreponemal-reactive sera are tested with a treponemal
Therefore, we encourage FDA to communicate and coordinate its proposal for testing requirements
with HRSA, the Organ Procurement and Transplantation Network (OPTN), and the United Network for
Organ Sharing (UNOS). These communication avenues must be pursued, prior to issuing final guidance
for HCT/P donor testing, and the FDA and HRSA need to provide guidance on how to treat shared donors
with discordant test results.
There is no evidence in the literature, either experimental or clinical, to suggest the transmission of
syphilis via corneal transplantation.
There is no evidence in the literature, either experimental or clinical, to suggest the transmission of
syphilis via corneal transplantation.10 Randolph attempted to establish the experimental transmission of
syphilis by transplantation of clear corneas from latently-infected rabbits.11 Randolph was unable to
confirm the transmission of syphilis as manifested by active keratitis or orchitis. Macsai and Norris
studied the effects of corneal storage conditions on the survival and infectivity of Treponema pallidum.
It was found that T. pallidum became inactivated within 24 hours when incubated in Optisol medium at
4°C under standard corneal storage conditions.12
There have been no reported cases of syphilis transmission due to corneal transplantation, even before
institution of the policy of screening donors for RPR reactivity. In view of this work in animals and the
absence of any documented human cases in the literature, it seems unlikely that clear corneas from
syphilitic donors are responsible for the transmission of this disease. A possible exception is the eyes of
infants with congenital syphilis in whom treponemas have been found in the noninflamed corneas.
Ocular syphilis is an unusual manifestation of the disease, typically occurring during the secondary stage.
Uveitis is the most common ocular manifestation of syphilis, but may include interstitial keratitis,
anterior, intermediate, and posterior uveitis, chorioretinitis, retinitis, retinal vasculitis and cranial nerve
and optic neuropathies. Except for the chancre of primary syphilis, which rarely involves the lids or
conjunctiva, ocular involvement in syphilis occurs in the secondary stage (usually associated with other
systemic findings) or in the late stages.13
EBAA Medical Standards require that a penlight or portable slit-lamp examination of the anterior
segment be performed prior to enucleation or in situ corneoscleral disc excision. Any inflammation
(e.g., conjunctivitis, keratitis, scleritis, iritis, uveitis) found would be considered an EBAA contraindication
for transplant, and those tissues would not be offered for surgical purposes (EBAA Medical Standards
D1.110.A.9.b and E1.100). This provides a further layer of safety.
In 1991, the EBAA Medical Standards implemented a policy of mandatory donor syphilis testing for all
member eye banks, in the belief that a positive syphilis serology might serve as a surrogate marker for
HIV-1 infection. Goldberg et al found a poor correlation between positive syphilis and HIV-1 serology
within a donor population as a result of a 1992 screening survey of 8932 donors.14 Based in part on
these results, the requirement for serologic screening for syphilis was eliminated from the EBAA Medical
Standards. However, the FDA has determined syphilis to be a relevant communicable disease and
disease agent (RCDAD) and requires syphilis testing of all ocular tissue donors.
Eye banks are unique among HCT/P establishments, because they perform active surveillance for
adverse reactions among the ocular tissue they distribute. Per EBAA Medical Standards, member eye
banks are required to request postoperative outcome information between three and six months after
transplant from the transplanting surgeon concerning possible adverse reactions on all corneal tissue
distributed by the eye bank (EBAA Medical Standard M1.500). Adverse reactions involving the
development of systemic infectious disease in a recipient would be reportable to both the EBAA through
our Online Adverse Reaction Reporting System (OARRS) and FDA through their MedWatch system.
There has never been a reported syphilis infection in the EBAA Online Adverse Reaction Reporting
System since its inception in 2004, nor via the paper records prior to that date.
The EBAA Medical Advisory Board, which consists of experts in the fields of Ophthalmology and eye
banking, regularly reviews the available data on transmission of communicable diseases associated with
corneal tissues. OARRS data is presented and reviewed at each semi-annual meeting of the EBAA
Medical Advisory Board. When evidence suggests a correlation between a communicable disease and
corneal transplant, the Board will recommend listing the condition as a contraindication to donation.
Increasing costs are absorbed by the health care system and eye banks.
Each additional required test adds to the cost of providing tissue for transplant. As more tests are
developed and made available, each test should demonstrate tangible benefit to the screening of
donors to justify the increased costs before being added to the list of required tests.
Payers are extremely sensitive to cost issues in today’s environment. CMS, (the Centers for Medicare
and Medicaid Services), under the U.S. Department of Health and Human Services (HHS), is the single
largest payer for corneal tissue, and currently reimburses facilities at the eye bank’s invoice cost for
processing. Additional costs imposed by changes in testing requirements may jeopardize this balance
and are particularly counterproductive in the absence of scientific support for increased safety
attributable to those changes.
Based on the costs of the kits used, the per test reagent costs for the qualitative nontreponemal tests
are fairly low ($0.18 to $0.40) in comparison to the treponemal tests, such as the FTA-ABS test ($2.13),
the Treponema pallidum particle agglutination (TP-PA) test ($2.14), and the EIA test ($2.33)6. Most
eye/tissue banks do not perform enzyme immunoassays; instead they will need to send clinical
specimens to contracted laboratories for syphilis testing. This practice increases the turnaround time
and delays corneal transplantation. The traditional approach (RPR screening) has a proven track record
and is suitable for HCT/P donors.
Finally, the FDA has not thoroughly evaluated the financial implications of implementing this test. These
costs include not only the direct costs of the test kits and related implementation, but also the indirect
costs to the health care system, including the loss of otherwise eligible donors. The per-test cost for
using an EIA screening test for syphilis in place of the diagnostic test is estimated to be an additional
$14-$35 per donor. If all donors were tested, the estimated annual testing costs for syphilis would be
increased by at least $829,094 ($14 x 59,221 donors). However, the far greater cost to the health care
system is the loss of human tissue due to false positive test results.
Closing Remarks
The EBAA thanks the FDA for the opportunity to comment on the draft guidance document. The
Association understands and appreciates the FDA’s efforts to help ensure the safety of human tissues
for transplant and prevent the transmission of communicable disease by HCT/Ps. We appreciate the
opportunity to work with you to ensure the safety of ocular tissue offered for transplant.
As was said at the outset, the EBAA has a long and valued history of working with the FDA and our other
transplant partners to develop an appropriate regulatory scheme to address emerging infectious agents.
These comments are intended to continue that collegial and cooperative spirit.
Kevin P. Corcoran, CAE
President & CEO
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2. Hooper, N. E., D. C. Malloy, and S. Passen. 1994. Evaluation of a Treponema pallidum enzyme
immunoassay as a screening test for syphilis. Clin. Diagn. Lab. Immunol. 1:477–481.
3. Reisner, B. S., L. M. Mann, C. A. Tholcken, R. T. Waite, and G. L. Woods. 1997. Use of the Treponema
pallidum-specific Captia Syphilis IgG assay in conjunction with the rapid plasma reagin to test for syphilis.
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9. AATB-accredited OPOs: Recovery-Related Survey Report, November 2006.
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11. Randolph ME. An experimental study of the possibility of transmitting syphilis by a corneal graft.
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12. Macsai, MS and Norris, SJ. OptiSol Corneal Storage Medium and Transmission of Treponema
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13. Kiss S, Damico FM, Young LH. Ocular manifestations and treatment of syphilis. Semin Ophthalmol.
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14. Goldberg, MA, Laycock, KA,Kinard S, et al. Poor correlation between reactive syphilis serology and
human immunodeficiency virus testing among potential cornea donors. Am J Ophthalmol. 1995;119:1-6.