Are Our Screening Algorithms Appropriate? Prospects for the Next 10 Years

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1 Are Our Screening Algorithms Appropriate? Prospects for the Next 10 Years IPFA/PEI 18 th International Workshop on Surveillance and Screening of Blood Borne Pathogens May 2011, Dublin, Ireland Jay Epstein, M.D. CBER, FDA

2 Are Our Screening Algorithms Appropriate? Value of risk factor screening Value of laboratory testing Limits of bacterial culture Challenges in parasitic detection New technology opportunities Diagnostic methods Pathogen reduction Stem cell based product manufacturing The hospital perspective on blood safety Personal speculations on the future

3 The Current Screening Paradigm Donor deferral based on epidemiologically determined risk factors for TTIDs (medical, geographical and behavioral risks) Laboratory testing for specific agents Serologic testing for antibodies and antigens NAT Bacterial detection in platelets

4 Historical Transfusion Risks of HIV, HCV, and HBV* Risk of Transmission per Unit of Transfused Blood Component HBV HIV HCV *Peterman TA, et al., Transfusion 1987;27: Busch, MP. Transfusion 2006;46: Zou, et al. Transfusion 2009; 49: and

5 Value of Risk Factor Based Deferrals Avoids collection of test positive units that could be released in error Reduces risk to recipients from window period collections Behavioral exclusions foster donation by persons with healthier lifestyles, possibly reducing some EID risk

6 HIV Related Behavioral Deferrals Reduce HIV Marker Prevalence in Donors 0.47% confirmed HIV+ in donor-age general population (McQuillan, 1994) 0.03% confirmed HIV+ in First Time Donors (REDS survey circa 1995) Estimated 93.6% (16 fold) reduction in HIV seroprevalence

7 MSM History Deferral Reduces MSM Behavior Prevalence in Accepted Blood Donors 4.1% prevalence of MSM - past 5 yrs in male general population (Laumann 1994) 0.57% MSM-77 risk in accepted male donors (Williams 1997) Estimated 86.1% (7.2 fold) reduction

8 IDU History Deferral Reduces IDU History Prevalence in Accepted Blood Donors 3.9% IDU since 1978 in general population (Dallas Household Survey 1994) 0.51% IDU-ever among accepted donors (Williams 1997) Estimated 86.9% (7.6 fold) reduction

9 Prevalence of Reported Behavioral Risks in Accepted Blood Donors* IDU-ever 0.5% Sex with IDU (12 mos) 0.4% MSM Ever (males) 2.4% MSM (males) 0.6% 1.2% (n=280) Sex with CSW (males) 0.5% Any deferrable risk 1.9% *REDS Donor Surveys

10 Value of Laboratory Testing Avoids transfusion of marker positive units But, Requires knowledge about the TTID agent Is limited by the sensitivity of the test technology Can be falsely negative (e.g. with viral variants) Enables monitoring of risk in donors Calculation of prevalence, incidence and residual risk yield knowledge of blood safety Studies of risk factors in positive donors permit improvements in donor selection

11 Safety Impact of Laboratory Testing (Based on ARC data for a,b ) Marker Positive Rate (#/100K) Residual Risk (#/100K) Risk Reduction Factor HBV a HCV b 37.43; est d 85% viremic HIV b a From Zou, et al. Transfusion 2010;50: and 2009;49: b From Zou, et al. Transfusion 2010;50: and 2010;50:

12 Value of NAT in Viral Disease Testing Reduction in Window Periods HIV: days vs. antibody tests HCV: days vs. antibody tests HBV: 7-12 days vs. HBsAg tests Reduction in Transmissions Approximately 5 HIV and 56 HCV transmissions per year were prevented by NAT (Stramer, et al., 2004) Interdiction of over 2000 WNV infected units since implementation of WNV NAT in 2003

13 Limits of Early Bacterial Culture (1) ARC experience 1 ( ) with BacT/ALERT: Sampling volume 8mL, 24hrs, with diversion pouch 781,936 collections, ~ 1.3 million components True positive (TP) rate ~ 167 per million collections 11 septic reactions: ~ 1 per 122,000 components 1 death: ~ 1 per 1.3 million components Sensitivity of BacT/ALERT culture at 24 hours based on reculture at expiration: 22-40% 2,3,4 1. Eder A, et al, Transfusion 2009;49: and Richard Benjamin AABB 2008 presentation 2. Dumont LJ, et al. PASSPORT study results. Transfusion 2010; 50: Murphy WG et al. Screening platelet concentrates for bacterial contamination. Vox Sanguinis 2008;95: Pearce S et al. Screening of platelets for bacterial contamination at the Welsh Blood Service. Transfusion Medicine 2011;21:25-32

14 Limits of Early Bacterial Culture (2) Verax PGD test post marketing studies* 18,449 apheresis platelet units, negative by early bacterial culture, were retested on day of transfusion by PGD test with positive results confirmed by culture A subset of 3,627 units had both PGD positive and negative results confirmed by culture 8 true positives picked up days 3 through day 5 (5 Coag Neg Staph; 2 Bacillus cereus; 1 Enterococcus faecalis) for a TP rate of ~ 1/2,306 = 433 per million 1 false negative tested on day 5 (concurrent culture grew Strep oralis-viridans group) for a FN rate of 1/3,627 False positive rate: 1/113 ~ 0.85% *Jacobs et al. Abstract and Oral presentation at AABB Baltimore 2010.Transfusion 2010;50: s2, 30A.

15 Challenges in the Detection of Plasmodia and Babesia Infections with Plasmodia and Babesia can be transmitted by transfusion of both RBCs and Platelets Plasmodia and Babesia cause chronic, asymptomatic infections with very low level parasitemias Plasmodia and Babesia infections can be transmitted by very small numbers of parasites Even the most sensitive nucleic acid based tests may fail to detect parasites in donors with low-grade, asymptomatic infections due to limitations of sampling

16 Limitations of Antibody Testing for Detection of Infections with Plasmodia or Babesia Antibody testing is highly effective to identify historic exposures to Plasmodia and Babesia parasites But, Infections with Plasmodia and Babesia result in highly specific antibodies detectable by IFA or ELISA For Plasmodia the window period from appearance of blood stage parasites to detectable antibodies is about 14 days (not known for Babesia) IgG titers may persist for months or years and cannot distinguish current from past infections. Antibody testing would then cause deferral of recovered donors who would not transmit malaria or babesiosis.

17 New Technology Opportunities Testing Multiplex NAT for arboviruses (WNV, Dengue viruses, Chikungunya) Nanoparticle based assays Microfluidics Alternative manufacturing Pathogen Reduction Extracorporeal Blood Cell Cultivation

18 Nanoparticle Based Diagnostics Nanotechnology is engineering at the atomic, molecular, or macromolecular scale, leading to controlled creation and use of structures with a length scale of nanometers (nm) At the nanoscale, physical, chemical, and biological properties of materials differ fundamentally from those of the corresponding bulk material e.g. color, melting point etc. opening new opportunities for process design Nanotechnology-based techniques could potentially provide a new generation of rapid, sensitive assays for simultaneous detection of multiple analytes in a miniaturized format.

19 PCR-free Nanoparticle-based Whole Genomic Assay for Rapid Detection of Nucleic Acids AAAAAA AAAAAA AAAAAA AAAAAA 15nm Au NP AAAAAA TTTTTT AAAAAA TTTTTT 15nm Au NP DNA/RNA target Hybridization Au-probe Hybridization Silver staining

20 Genomic Oligo-Array for Detection of HIV Subtypes, CRFs and Drug Resistant Mutations Subtype A B C D H F J K CRF01_AE CRF02_AG Gag Pol Env Predicted genotype: CRF01_AE / 02_AG / B

21 Europium NP-based Immunoassay (ENIA) Using Time-Resolved Fluorescence SA-Eu NP r = R 2 = p < primary antibody target 2 nd antibody biotin anti-2 nd antibody SA-Eu NP SA Eu + NP LOD: 0.5 pg/ml or 0.5 ng/l 21 fmol/l or 2 attomoles of p24 (24KDa) Tang S and Hewlett IK. J. Infect. Dis. 2010; 201 (suppl 1):S59-S64

22 On-Chip Detection of HIV p24 Proteins Using Europium Nanoparticles Perkin Elmer Wallac Plate Reader

23 Microfluidic Chip-Based Rapid, Multiplexed Pathogen Detection Fully integrated microchip for rapid HIV diagnosis in resourcelimited settings; up to 4 pathogens can be multiplexed in above format Manual pumping and on chip reagent storage Silver Cluster Porous polymer detection elements Label free SERS detection using monolith detector containing silver clusters

24 Improving Sensitivity of NAT for Plasmodia and Babesia Sample concentration and removal of the interfering substances from the red cell (e.g., hemoglobin) Targeting high copy number genes for amplification

25 P. falciparum NAT: Sample Concentration and Hemoglobin Removal by Saponin Lysis of RBC 100 μl 500 μl 5 ml Normal blood parasite 3-1 parasites 4-10 parasites parasites parasites parasites parasites 1 - Normal blood parasite 3-5 parasites 4-50 parasites 5 5x10 2 parasites 6 5x10 3 parasites 7 5x10 4 parasites 8 5x10 5 parasites 1 - Normal blood parasite 3-1 parasites 4-10 parasites parasites parasites parasites parasites PCR sensitivity: 2-10 P. falciparum parasites/ml of blood ,000 fold more sensitive than thick-film microscopy S. Kumar et al., unpublished)

26 Merits of Pathogen Reduction Technology as an Alternative to Donor Screening and Testing Advantages Shown effective against many organisms including some emerging pathogens May prevent GVHD and other wbc related adverse events Disadvantages May not be effective against all organisms May not be 100% effective even against sensitive pathogens Current technologies are not applicable to all types of transfusion products May have toxicity due to residual compounds May damage the transfusion product May lead to alloimmunization by neoantigens May cause unexpected adverse events

27 Pathogen Reduced Platelets Have Lower Corrected Count Increments (CCI) Clinical Trial Patients in study % of plasma stored platelets CCI at 1 hr P value SPRINT 1, a % < HOVON 1, b % < MIRASOL 2, c % < = UVA/psoralen 2 = UVB/riboflavin a = McCullough, J et al Blood Sep 1;104(5): b = Kerkhoffs JL et al. Br J Haematol Jul;150(2): c = Goodrich et al. Transfusion, May 2010

28 Hemostatic Efficacy for UV A/psoralen (Intercept) Treated Platelets SPRINT study Control platelets Pathogen reduced platelets Proportion of pts with Grade 2 bleeding Days of Grade 2 bleeding % patients with Grade 2-4 bleeding 58.5% 57.5% NS for inferiority HOVON study Control platelets Pathogen reduced platelets % of patients with Grade 1-3 bleeding p p

29 Hemostatic Efficacy for UVB/riboflavin (Mirasol) Treated Platelets MIRASOL study % of patients with Grade 2-4 bleeding Control platelets Pathogen reduced platelets NS p

30 FDA Perspective on Pathogen Reduction Pathogen Reduction of labile blood products could improve blood product safety, especially for platelets, but should not add greater risks Clinical trials with Pathogen Reduced red cells have demonstrated antibody generation Clinical trials with Pathogen Reduced platelets have demonstrated decreased efficacy and associated adverse events including acute lung injury in the SPRINT trial. Further clinical trials of current technologies are needed to resolve FDA s concerns over decreased efficacy and increased adverse events seen with Pathogen Reduced platelets

31 In Vitro Production of Stem Cell- Derived Transfusion products -1 Small scale production of red cells and platelets from stem cells is already possible Benefits of this technology might include generation of universal red cells that would not need typing Continued supply Pathogen reduced during processing Extended storage due to cell synchronization

32 In Vitro Production of Stem Cell- Derived Transfusion products -2 Major hurdles that remain are scale up of process that produces uniform product with appropriate quality control automation High cost per transfusion product due to cytokine cocktail requirements concerns about transfusion of undifferentiated pluripotent stem cells Efforts are continuing in the hope that this technology will transform transfusion medicine

33 The Hospital Side of Transfusion Focused on patient care Requires good transfusion practices Staff education Blood management

34 The Biggest Risks Are Not Infections HIV HCV HBV Death: General anesthesia Death: Medical error Death: Hosp. infection vcjd Bacteria in platelets Mistransfusion TRALI GVHD Cardiac Risk per unit. Modified from S. Dzik, MGH, Boston Metabolic risk in neonates Under transfusion?

35 Transfusion Safety Matters In the Hospital Issue Recruit Screen donor Collect & Prepare Infectious disease tests Pre-transfusion testing Medical decision to transfuse Administer (bedside) Monitor & evaluate Product Hospital-based steps Process While products are safer than ever before, a lack of progress exists for risk reduction in the hospital-based steps of transfusion care. After W.H. Dzik

36 Categories of Events Reported by the SHOT Program in England, TRALI Infections GVHD PTP Delayed reaction Incorrect blood transfused Acute reaction

37 Current Dilemmas in Transfusion How best to address EID threats How to reduce hospital transfusion errors When to transfuse red cells and platelets Safety of older stored red cells Optimal management of severe bleeding Better prevention of TRALI

38 Personal 10 Year Speculations -1 Better testing > Pathogen Reduction > Novel Manufacturing In the next five years: Additional sensitive bacterial testing will be performed at the time of platelet release HBV NAT will replace HBsAg Donor blood will be tested for plasmodia, babesia and dengue viruses (plus CHKV in some regions) B19 and HAV testing will be elevated to donor screens There still will not be donor testing for vcjd New infectious threats will continue to arise!

39 Personal 10 Year Speculations - 2 In the next ten years: Pathogen reduction of Whole Blood and components will be established, and then Testing will be discontinued for syphilis, WNV, CMV, Chagas disease and anti-hbc Deferrals for malaria will be discontinued Some behavior-based deferrals will be discontinued (e.g. for MSM)

40 Additional long term complications of transfusion will be discovered! Personal 10 Year Speculations - 3 In the next ten years (continued) We will have better understanding when blood products should be transfused Management of severe bleeding will become evidence based; HBOCs will still be under study We will know whether older stored blood is safe Blood for emergency use will be manipulated to remove ABO and Rh antigens reducing the need for Type O, Rh negative donations Antigen null and rare red cells types will be generated in extracorporeal bioreactors