1

Objectives
• to highlight the clinical implications of neutropenia
• to systematically review the literature to assess the potential benefit of granulocyte transfusions given as prophylaxis against infection in the setting of neutropenia
• critical appraisal of a systematic review
2

“Granulocyte transfusions for preventing infections in patients with neutropenia or neutrophil dysfunction (Review) ”
Massey E, Paulus U, Doree C, Stanworth S
The Cochrane Collaboration
2009

• infections in the setting of neutropenia are often severe and life-threatening despite appropriate antimicrobial therapy
• neutropenia is usually encountered postchemotherapy or post-hematopoietic stem cell transplantation
• G-CSF does not lead to appreciable granulocyte production in the setting of neutropenia
4

Introduction
•
• granulocyte transfusions may be potentially beneficial to neutropenic patients
(prophylactic vs. therapeutic) however...granulocytes for transfusion purposes are difficult to procure/process/store:
apheresis procedure is required (takes several hours)
- separation of the granulocyte component is difficult
- donor exposure to G-CSF (? safety concerns)
- difficulty in securing donors (random vs. directed)
- granulocytes have a finite storage period at room temperature (several hours)
- product irradiation required (risk of TA-GVHD)
- cross-match compatible product required
5

Introduction
• dose of transfused granulocytes is important
• studies performed prior to the availability of G-CSF involved granulocyte dosages that were lower than the minimally acceptable dose of 1 x 10 10 cells per transfusion and showed no benefit
(Cochrane Reviews: Vamvakas 1997 Stanworth 2005)
• the use of granulocyte transfusion disappeared from clinical use from ~1985-1995 due to improvements in antimicrobials and supportive care
6

•
•
Introduction
However... a single donor stimulated with G-CSF and steroids can procure a granulocyte dose of 5-10 x 10 10
(r enewed clinical interest in this area)
• Adkins (1997) reported a mean ANC increment of
1000/microL that was maintained for 1 to 1.5 days with a mean granulocyte dose of 5.1 x 10 10
• limited evidence exists to demonstrate that transfused granulocytes maintain their function
7

Determinants of the efficacy of prophylactic granulocyte transfusions: a meta-analysis
Vamvakas EC, Pineda AA. Journal of Clinical Apheresis 1997;
12:74-81
• Objective : meta-analysis of studies of prophylactic granulocyte transfusions to identify the determinants of efficacy of this intervention
• Selection Criteria :
RCTs from 1970-1995 involving the efficacy of prophylactic granulocyte transfusions
• Results : 8 RCTs eligible. Transfusion of adequate doses of granulocytes reduced the RR of infection, death, and death from infection in transfused patients vs. controls (RR=0.075,
0.224, 0.168, respectively; P<0.05)
8

Granulocye transfusions for treating infectons in patients with neutropenia or neutrophil dysfunction
Stanworth S, Massey E, Hyde C, et al. Cochrane Database Syst
Rev 2005
• Objective : To determine the effectiveness of granulocyte transfusions compared to no transfusion for treating patients with neutropenia
• Selection Criteria :
RCTs involving THERAPEUTIC granulocyte transfusions to patients with neutropenia
• Results : 8 RCTs involving 310 patients
9

Granulocye transfusions for treating infectons in patients with neutropenia or neutrophil dysfunction
Stanworth S, Massey E, Hyde C, et al. Cochrane Database Syst
Rev 2005
• Results :
RR for mortality for 6 trials was 0.64 in favour of transfusion (95% CI 0.33-1.26); chi-square 11.3; I 2 =56%
(significant clinical heterogeneity between studies)
- RR for mortality for 4 studies that transfused granulocyte doses greater than 1.0 x 10 10 was 0.37 (95% CI 0.17-0.82); chi-square 3.9; I 2 =23%
• Conclusion : Inconclusive evidence exists from RCTs to support or refute the use of granulocyte transfusions in neutropenic patients
10

Granulocyte transfusions for neonates with confirmed or suspected sepsis and neutropenia
Mohan P, Broklehurst P, Cochrane Database Syst Rev 2003 Mar
16; 3
• Objective : To determine the efficacy and safety of granulocyte transfusions as adjuncts to antibiotics for the
TREATMENT of confirmed or suspected sepsis in neonates with neutropenia in reducing all-cause mortality (and several secondary outcomes)
• Selection Criteria : RCTs and quasi-randomized studies involving neonates with suspected or confirmed sepsis and neutropenia who received granulocyte transfusions at any dose or duration compared with placebo or no granulocyte transfusion
11

Granulocyte transfusions for neonates with confirmed or suspected sepsis and neutropenia
Mohan P, Broklehurst P, Cochrane Database Syst Rev 2003 Mar
16; 3
• Results:
- 4 RCTs involving 79 neonates
- RR for all-cause mortality was 0.89 (95% CI 0.43-1.86) with no statistical heterogeneity in the results
• Conclusion: Inconclusive evidence exists from RCTs to support or refute the use of granulocyte transfusions in neonates with sepsis and neutropenia to reduce mortality (and morbidity)
12

Introduction
• no systematic reviews examining the efficacy of
PROPHYLACTIC granulocyte transfusions in the setting of neutropenia have been performed in over ten years (Vamvakas 1997)
• no prior Cochrane review exists which examines the use of PROPHYLACTIC granulocyte transfusion in neutropenic patients using a significant number of trials that would have used
G-CSF
13

“Granulocyte transfusions for preventing infections in patients with neutropenia or neutrophil dysfunction (Review) ”
Massey E, Paulus U, Doree C, Stanworth S
The Cochrane Collaboration
2009

• systematic review to assess the effectiveness and safety of prophylactic granulocyte transfusions in patients with neutropenia or disorders of neutrophil function compared with a control population not receiving this intervention for preventing:
- mortality
- mortality due to infection
- evidence of infection
- adverse events
15

Cochrane Review: Outcomes
• Primary Outcome :
overall mortality
• Secondary Outcomes :
mortality due to infection
- number of infections
- number of days with fever
- number of days on treatment with antimicrobials
- neutrophil count increment post-transfusion (x10 9 /L)
- duration of neutropenia reversal after transfusion
16

Cochrane Review: Outcomes
• adverse events for patients or granulocyte donors
- death
- hospitalization
- significant disability
- requiring discontinuation of intervention
17

Cochrane Review
• Search strategy (up to October 2008):
the Cochrane Central Register of Controlled
Trials (CENTRAL) 2008
- MEDLINE
- EMBASE
- other specialized databases (including ongoing trial databases)
- contact with experts in the field
- article reference list searches
18

Cochrane Review
• Study Selection Criteria:
studies involving patients with neutropenia or inherited disorders of neutrophil function (excluding neonates) in which granulocyte transfusions were given as prophylaxis prior to the development of documented infection compared to a control group not receiving granulocyte transfusions
• RCTs and quasi-randomised, controlled studies
(allocation to receive granulocyte transfusion was dependent upon the availability of suitably-matched donors)
19

Cochrane Review
• Control group:
- prophylactic granulocyte transfusions were not administered
• subgroup analysis:
- performed on the study outcomes based on the dose of granulocytes transfused
20

Cochrane Review
• two review authors independently assessed studies for eligibility and extracted data onto study specific data extraction forms
• criteria for evaluation of study methodological quality:
generation of allocation sequence
- concealment of treatment allocation schedule
- blinding of outcome assessment
(for clinician, participant, and outcome assessor)
- the proportion of randomized participants included in the main analysis
21

Cochrane Review
• studies were assigned a label of adequate, unclear, or inadequate for each of the criteria
22

Cochrane Review
• Study details collected:
place and date of publication
- population characteristics
- study setting
- detailed nature of study intervention
- detailed nature of study comparator
- detailed nature of study outcome
- use of therapeutic granulocyte transfusions during the study
- use of colony-stimulating factors in recipients
- use of prophylactic and therapeutic antimicrobials
- method of preparation and source of transfused granulocytes
23

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Cochrane Review
• Review Manager 5 was used for data analysis
main method of analysis was qualitative
( conclusions were based on the patterns of results across studies)
• statistical heterogeneity between studies was tested using the chi-squared and I 2 test
(a statistical significance level of < 0.10 was interpreted as evidence of heterogeneity)
• the main summary outcome was a summary risk ratio (dichotomous data) and a weighted mean difference (continuous data)
- fixed and random effect models were used
25

Cochrane Review: Included
Trials
26

Cochrane Review:
Results
• ten prospective clinical trials met inclusion criteria
(8 from US, one from Spain, one from UK)
• control arm received no prophylactic therapy except in one trial in which the control group received specific prophylactic antibiotics
• all trials were conducted prior to 1987 with the exception of one trial from 2006
27

Cochrane Review:
Results
• Granulocyte donor priming:
- four trials did not administer any form of medication to the donors to increase the granulocyte yield
• five trials administered steroids to donors
- dexamethasone, hydrocortisone, prednisone
• one trial administered G-CSF to donors
(Oza 2006)
28

• Granulocyte procurement method:
8 trials used either intermittent or continuous flow centrifugation
- one study used only filtration leukapheresis (FL)
(Winston 1980); FL is rarely used currently
- one study used both FL and continuous flow centrifugation (Clift 1978)
29

Cochrane Review:
Results
• Granulocyte transfusion triggers:
- 0.2 x 10 9 in two studies
- 0.5 x 10 9 in six studies
• Donor selection:
three studies did not assess leukocyte (HLA) compatibility between the granulocyte recipient and donor
- seven studies selected donors on the basis of some criteria of HLA compatibility
30

• most of the participants in the studies had acute myeloid leukemia (AML) +/- allogeneic stem cell transplantation
31

• Study Sample Size :
the median number of patients enrolled, randomized and analyzed in all the studies was 55
(range 18-151)
- only one trial (Oza 2006) made an attempt to justify the statistical analysis or required sample size
(limited evidence was available from the remainder of the trials on sample sizes required to power the trial around a main outcome)
32

Cochrane Review: Results
• eight studies randomly allocated patients to receive prophylactic granulocyte transfusions with no other intervention
• one trial (Oza 2006) was quasi-randomized
(allocation to prophylactic granulocyte transfusion was based on ABO-matching and availability of donors)
• one trial (Petersen 1987) randomized between prophylactic granulocyte transfusions and prophylactic systemic antibiotics (Vancomycin, Ticarcillin)
33

•
data on neutrophil increment one-hour postgranulocyte transfusion was available from five studies
CCI = count increment (mm 3 ) x body surface area (m 2 ) divided by the number of granulocytes transfused (x 10 10 )
• total number of granulocyte transfusions given per patient was 2 to 23
(the ten included studies had a variable transfusion schedule)
• granulocyte dose varied between studies:
- for nine studies the mean range was 0.9 x 10 10 (Sutton 1982) to 5.9 x 10 10 (Oza 2006)
- one trial did not state dose (Petersen 1987)
34

Cochrane Review:
Results
• differences were found between studies with respect to the cointerventions given to patients
(antibiotics)
• specific regimens for anti-fungal therapy
(Amphotericin B) were stated explicitly in only two trials (Oza 2006, Winston 1980)
35

Cochrane Review:
Results
• definition of infection used to recruit uninfected patients into the study or to identify those who became infected during study:
- temperature
- clinical signs of infection
- isolation of organisms
• different criteria for the definition of infection were used by the studies (such as fever definition)
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40

41

Cochrane Review:
Results
• Subgroup analysis - excluding trials which transfused granulocyte doses of < 1.0 x 10 10
(Strauss 1981, Sutton 1982)
42

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44

45

• blinding was not achieved in the trials since it is diificult to apply in this setting
• no data was available on whether or not outcome assessors were blinded in any of the trials
• adverse event data was reported for all trials except one (Oza 2006)

• a high rate of adverse reactions were seen in recipients of granulocyte transfusions:
- fever
- TA-GVHD (one death)
- HLA-alloimmunization
- pulmonary reactions
• the predominant reactions for granulocyte donors were febrile/shivering episodes
(reported in two trials)

Cochrane Review:
• prophylactic granulocyte transfusions given to neutropenic patients at a dose of at least 1 x 10 10 do not decrease the risk of overall mortality but may possibly reduce the risk of mortality from infection and reduce the number of infective episodes
• the majority of studies included in this systematic review are dated and involved the transfusion of lower numbers of granulocytes than what is currently recommended; standards of supportive care have also improved

Cochrane Review:
• granulocyte transfusions cannot be recommended outside the setting of a clinical trial due to the resource and cost implications:
- small sample sizes in studies
- heterogeneous study definitions of infection
• larger clinical trials that are adequately powered are required before the potential benefits of granulocyte transfusions can be validated
• an NHLBI sponsored RCT studying THERAPEUTIC granulocyte transfusion using currently available doses in neutropenic patients is currently underway in the USA

• Systematic review: using methods designed to reduce the likelihood of bias
• Meta-analysis: a systematic review that uses quantitative methods to summarize the results

•
Are the results valid?
- yes
(with respect to the time period and context in which the majority of the studies were performed)
however… the study results were influenced in a systematic fashion in that the majority of the trials involved granulocyte transfusions of < 1.0 x 10 10
• Did this review address a focused clinical question?
- yes
(do prophylactic granulocyte transfusions improve patient outcomes in the setting of neutropenia?)

Critical Appraisal: Systematic Reviews
• Were the criteria for article inclusion appropriate?
- yes
(RCTs which allocated uninfected neutropenic patients to receive prophylactic granulocyte transfusions or not)
• Is it unlikely that relevant studies were missed?
yes
(the number of studies published on this subject are few and generally dated)
• Was the validity of the included studies appraised?
yes
(the criteria for the evaluation of study methodological quality was systematically assessed and explicitly stated)

Critical Appraisal: Systematic Reviews
• Was the assessment of studies reproducible?
- yes
(standardized data extraction forms were used which recorded key features of each of the studies that were included in the systematic review)
• Were the results similar from study to study?
no
- variation existed in the results between studies
- amount of weight carried by each study with respect to outcome varied significantly
- end points for the outcome analysis varied
- differences existed in the definition of some study outcomes
(eg. infection)

Critical Appraisal: Systematic Reviews
• What are the overall results of the review?
- prophylactic granulocyte transfusions given to patients with neutropenia at a dose of at least 1.0 x 10 10 do not decrease overall mortality but may reduce mortality due to infection
• How precise are the results?
- the confidence intervals of the relative risk (RR) statistic for the study outcomes were wide
- there was no evidence of significant heterogeneity in the main outcomes when all 10 studies were included which suggests that variation in results may have occurred by chance alone

Critical Appraisal:
Systematic Reviews
• Will the results help me in my patient care?
- not currently and possibly not in the future either since the use of prophylactic granulocyte transfusions is not being actively investigated
(therapeutic granulocyte transfusions may become indicated once definitive evidence of benefit exists)
• Can the results be applied to my patients?
- not currently outside of the investigational setting

Critical Appraisal:
Systematic Reviews
• Were all clinically important outcomes considered?
yes
(overall mortality, mortality due to infection, number of episodes of infection)
• Are the benefits worth the harms and costs?
- no
(harms to the granulocyte recipient and donor and resource utilization are significant factors to consider)

Questions or comments?