Infusion of Culture Positive Stem Cell Products FDA Liaison Meeting June 16, 2006 D. A. Gastineau Mayo College of Medicine Overview Background-historical perspective Questions to be addressed Specific Experience at Mayo ISCT Survey Changes to practice of respondents influence on sterility results Closed Systems Conclusions Background
Human bone marrow and PBPC transplant products have traditionally been sampled for bacterial contamination A small percentage of these products have positive cultures Known culture positive products have commonly been infused However, strict interpretation of the new GTP regulations prohibit this practice Experience at Mayo 7233 HPC products collected from January 1998 through March 2006 2118 transplants performed Review of medical records for evidence of adverse reactions,
toxicity and post-transplant blood cultures for the 69 patients (3% of total) who received positive products. Collection and Transplant Activity Total Collections 7233 Auto BM 131 Allo BM 127 PBPC 6838 DLI
137 Transplants Auto 1764 Transplants Allo 354 Sterility Testing at Mayo Before 3/04 1 ml was injected in an isolator tube and incubated for 28 days After 3/04 1 ml was injected in peds Bactec bottle and incubated for 5 days. Samples were taken from the product
upon arrival in the laboratory and after all processing before freezing Frequency of Positive Products Total Products Apheresis Bone Marrow All Collections 7233 6975 258 Culture positive (%) 119 (1.6%)
Sources of Bacteria in Product Cultures Donor (patient) Introduced during collection Introduced during processing Introduced during sampling Introduction during thawing process Did not examine Post Thaw Culture Concordance Rate (n=67) % Culture Positive 100 75 50 25 0 Donor/Patient as the Source of contamination
Preprocess sample=A Positive Products Products from Culture Positive Patients Total Sample A Sample A&B 119 43 29 32 (27%) 2 (5%) 21 (72%)
Sample B 47 9 (19%) Postprocess sample=B Culture Positive Products When two cultures are positive (the A and B cultures), 21 of 29 or 72% of patients had concomitant bacteremias documented by blood culture. The PATIENT is a major source of bacteria Organisms from HPCs
Staphylococcus lugdunensis 1 1 Group A streptococcus 1 1 Chaetomium sp. 1 Chryseobacterium sp 1 Clostridium perfringens
1 Methylobacterium sp. 1 Pseudomonas fluorescens/putida 1 Infusion of Positive Products Total Number of 95 Patients with positive products collected Total Positive 119 Products collected Total Patients Receiving Positive Products
Total Positive Products Infused 69 88 Figure 2 100 Day Survival Following Infusion of Culture Positive Products Percent Surviving 100 75 p = 0.419 Controls n = 2046 50 Culture Pos n = 69
25 0 0 10 20 30 40 50 60 70 80 90 100 Days Conclusion Clinical Significance of infusion of positive products Minimal acute toxicity or adverse reactions Equivalent short-term and longterm survival Survey Sponsored by ISCT Goals
Obtain general information about the current practice of hematopoietic stem cell therapy Obtain preliminary information concerning experience with safety of culture-positive products Overall Summary: 177 Reporting Institutions Institution/Organizational Unit 140 119 120 100 80 60 40 20 29
26 3 0 Stand alone Stand alone Clinical transplant collection facility processing facility program Combined clinical, collection, processing facility Survey Question: Does your institution have a policy for handling culture-positive products? 9% 1%
Yes No Not sure 90% Policies encompass these elements Evaluation of the patient for current antibiotic use and/or use of prophylactic antibiotics if product is used, 120 Informed consent of the patient if product is used, 76 Infusion of the product w ith positive culture , 118 Notification of the patient's physician, 150 Involvem ent of the cell
therapy lab director, 143 Investigation of the positive culture, 146 0 20 40 60 80 100 120 140 160
Types of Products (92 Respondents) 70000 60000 65366 50000 48372 40000 30000 20000 12547 10000 5005 0 A R U To ut el R
ta D at o l ed PB PB SC PB SC /D SC LI /D LI Products Frequency of Positive Products 40000
1.7% 1.4% Infusion of positive products: Institutional Responses Has your institution ever infused or released for infusion a PBPC or DLI product: 117 Yes 64 (67%) That was known to be culturepositive before the infusion? 53 No 71
That became culture-positive after the infusion? 5 Not Sure 18 0 20 40 60 80 100 120
140 Test Methods for Sterility 15% BacT/Alert 37% 8% Bactec CFR/USP compliant method Other (Please specify) 40% Distribution of Organisms Found 15% 2% 1% 6%
Propionobacterium species Corynebacterium Micrococcus Klebsiella species Clostridium species E. coli Enterobacter Stenotrophomonas maltophilia Pseudomonas aeruginosa Other gram negative rods Candida species
Aspergillus species Other Association With Donor Bacteremia 32% of positive cultures reported to be associated with a positive culture in the patient/donor within 5 days before or after collection Deaths Associated with Infusions Of 91 respondents 4 reported deaths likely related to infusion 0 were felt to be due to microbial contamination 1 response was excluded as it
reported 6 deaths but fewer than 100 infusions and was otherwise very incomplete ISCT Survey Respondents Collection/processing changes introduced to reduce contamination Clean room facilities introduced No effect Second cultures sent from frozen samples If negative, presumed to be false positive All products since April 2003 have been in cGMP facility, Grade A critical area, Grade B background No change in rates Validated blood culture process, discontinued use of multi-use heparin vials
Reduction from 4% to 1.9% between 2003 and 2005 ISCT Survey Respondents Collection/processing changes introduced to reduce contamination Implemented new cleaning of BSCs, robust changeover procedures, increased BSC preventive maintenance Process in BSC, clean with 70% sterile alcohol between each product processed.
More strict gowning procedures, including use of sterile gloves. Perform EM daily Innoculate cultures for microbial testing in BSC in cell processing lab and then transport to microbiology. GMP/GTP training performed for all staff in Cell Processing and Microbiology departments including using sterile technique. Rearrangement of microbiology laboratory to accommodate microbial cultures for cellular products and to incubate all of these cultures in an isolated incubator. Perform tracking and trending of all positive cultures. No effect on rates seen ISCT Survey Respondents Collection/processing changes introduced to reduce contamination We used to culture every product immediately after collection and after processing. We reduced cost of culture and removed an unnecessary step.
We have implemented additional training regarding the line connections to reduce possible contamination. We had our infection control department observe all steps of the process to make suggestions to improve our handling and reduce possible contamination in the laboratory. Overall our number of positive cultures has dropped from approximately 5.5% to less than 4%. In 2005 we did not have any contaminated products. (?) Changes Introduced to Reduce Infection Risk and Effects Introduction of sterile sleeves Sterile gloves No longer perform separate fungus culture. Reduced the number of positive cultures related to contamination by reference lab. (no
numbers given) What is a Closed System? Closed . . . an isolated system having no interaction with an environment. Dictionary of Cybernetics and Systems To be completely closed a product should not be exposed to the external environment from beginning to end of the processing. Is this feasible? Collection: Venipuncture Sterile dockingadding reagents Sampling Infusion What is a Closed System? What would be a closed system? A container with all necessary
additives and vessels for processing attached to an original collection container Final vessel disconnected from original set of containers BUT: How to sample in process (also separate sample bags?) What is a Semi-closed System? Definition varies widely Generally refers to processes which have been adapted to bags from open processes such as ficoll-hypaque Tsang, Transfusion, 2001 What is a Functionally-closed System? Functionally-closed systems
Varies as well Processing cord blood with bags attached to central processing kit, valves to open/close for each process. Sepax-S100, Biosafe S.A. Zingsem, Transfusion, 2003 Product positive rate7.5%, similar to that of literature Unable to demonstrate superiority of functionally-closed system Functionally Closed System Fluids intrinsic to sterilized kit No flexibility of anticoagulation Sterile filters used for added reagents How Closed is Closed? A matter of degree, with nothing
completely closed as some air and starting material (blood) enter the system and may not be sterile. Closed remains a relative term Clinical Balance Risk of Infusion of Positive Products Very low with the current clinical practice of often giving antibiotics, but even without antibiotics, symptoms are few Vast majority of programs have SOPs addressing culture-positive products Alternatives to use of positive products No treatment Recollection
Risk of Recollection Healthy donor may need catheter reinserted Autologous donor may have underlying disease increasing donation risk Risks of Collection During period of report Two patients with amyloid died during mobilization/collection (not while on machine) One central catheter migrated to pericardial space One central catheter created AV fistula in thorax
Strategies for Reducing Positive Culture Rates Improved screening of donors Drawing blood cultures 48 hours prior to collection Cost: 100-200 blood cultures to detect a bacteremia, and difficult to measure benefit Some bacteremias are transient (clostridium) and wont be detected Clean room environment does not have a clear benefit Closed systems-some additional protection for post-donor sources Summary Infusion of culture-positive HPC products appears to be associated with minimal toxicity when
associated with usual clinical practice and precautions The type of bacterium detected may affect the clinical decision whether or not to use the product HPCs are not analogous to blood products in ease or risk of replacement Overall risk to the patient AND donor for recollection must be balanced against the assessed risk of infusion of culture-positive product
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