Background
Interim Control Event Rate (IControlER) | The number of events observed among control participants at some planned interim point into the trial divided by number of control participants admitted at that same planned interim point (e.g., a planned interim point can be 6 months from the start of the trial) |
Example: • Total number of deaths in the placebo group, 6 months from the start of the trial = 15 • Total number of participants in the placebo group, 6 months from the start of the trial = 250 • Calculation: 15/250 = 0.06 or 6% | |
Therefore, the Interim Control Event Rate at the trial’s interim analysis, 6 months from the start of the trial, is 6% | |
Interim Combined Event Rate (ICombinedER) |
“The total number of events observed at some planned interim point into the trial divided by the total number of participants admitted at that same planned interim point (e.g., a planned interim point can be 6 months from the start of the trial or after enrolling a certain number of participants)
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Example: • Total number of deaths in both the placebo group and new intervention group, 6 months from the start of the trial = 80 • Total number of participants in both the placebo group and the new intervention group, 6 months from the start of the trial = 700 • Calculation: 80/700 = 0.114 or 11.4% | |
Therefore, the Interim Combined Event Rate at the trial’s interim analysis, 6 months from the start of the trial, is 11.4%.” [8] | |
Adaptive Conditional Power (ACP) |
“The probability of rejecting the null hypothesis of no effect by the end of the trial (i.e., finding a statistically significant effect in favor of the intervention), at some predetermined interim point in the trial when the adaptive conditional power is scheduled to be calculated. The assumption made is that the observed interim effect (i.e., relative risk reduction) in the trial will remain the same until the end of the trial
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Example statement:
Given the interim data (data collected 2 years into the trial that is planned to last for 3 years), and assuming the observed interim effect (i.e., relative risk reduction) at the 2-year point to be the true effect for the remainder of the trial, the probability of rejecting the null hypothesis of no effect (i.e., finding a statistically significant effect in favor of the intervention) at the end of the trial is 60%.
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The following pieces of information are used to calculate Adaptive Conditional Power at trial interim:
• Control event rate and experimental event rate • Information Fraction; a ratio of the planned sample size and the number of patients recruited in the trial at the interim analysis • Z score and B value at interim • Drift parameter.” [8] | |
Unconditional Conditional Power (UCP) |
“The probability of correctly rejecting the null hypothesis of no effect at the end of the trial (i.e., finding a statistically significant effect in favor of the intervention) and accepting the alternative hypothesis when indeed the alternative hypothesis is true, at some interim point in the trial
The following pieces of information are used to calculate Unconditional Conditional Power at interim:
1. The hypothesized treatment effect at the design stage (i.e., relative risk reduction) of the trial, assuming the hypothesized treatment effect at the design stage to be true and correct for the remainder of the trial 2. The sample size calculated at the design stage for the trial and 3. The combined event rate calculated at the trial’s interim, assuming this rate to be true for the remainder of the trial |
Example statement:
Given the interim combined event rate and assuming the treatment effect (i.e., relative risk reduction) hypothesized at the design stage of the trial to be true for the remainder of the trial, the probability of correctly rejecting the null hypothesis of no effect (i.e., finding a statistically significant effect in favor of the intervention) at the end of the trial is 89%.” [8] |
Methods
Design of survey
Constructing and testing online survey
Sampling
Target group and sampling
Data collection and analysis
Results
Respondent demographics
Number of trials in which respondent has been involved
a
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Number of trials the respondent has been involved with that had a Data and Safety Monitoring Board (DSMB) monitoring the trial
b
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Number of trials | n (%)q | Number of trials | n (%)q |
None 1 to 5 trials 6 to 10 trials 11 to 15 trials More than 15 trials Unknown A | 4 (1.1) 20 (5.4) 25 (6.7) 23 (6.2) 131 (35.3) 168 (45.3) | None 1 to 5 trials 6 to 10 trials 11 to 15 trials More than 15 trials UnknownB | 10 (2.7) 34 (9.2) 37 (10.0) 28 (7.5) 88 (23.7) 174 (46.9) |
Number of trials the respondent has been involved with that had some form of private industry sponsorship
c
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Primary profession by training
d
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Number of trials | n (%)q | Main profession | n (%)q |
None 1 to 5 trials 6 to 10 trials 11 to 15 trials More than 15 trials UnknownC | 29 (7.8) 69 (18.6) 25 (6.7) 14 (3.8) 64 (17.3) 170 (45.8) | Mathematician/statistician/biostatistician Methodological scientist/research methodologist Physician Epidemiologist Research or clinical trial coordinator Ethics specialist Trialist Analyst Computer programmer Trial manager Trial monitor UnknownD | 156 (42.0) 21 (5.7) 10 (2.7) 5 (1.3) 3 (0.8) 2 (0.5) 2 (0.5) 1 (0.3) 1 (0.3) 1 (0.3) 1 (0.3) 168 (45.3) |
Usual work setting of respondents
e
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Other work settings of respondents
f *
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Place of work | n (%)q | Other places of work | n (%)q |
University or academic institution Private or contracted research company Pharmaceutical company Government research group Hospital Government regulatory body Academic university hospital Medical device company Private practice Retired UnknownE | 123 (33.2) 28 (7.5) 17 (4.6) 13 (3.5) 10 (2.7) 5 (1.3) 3 (0.8) 1 (0.3) 1 (0.3) 1 (0.3) 169 (46.0) | Hospital University or academic institution Pharmaceutical company Private or contracted research company Government research group Medical or health clinic Government regulatory body Medical device company Private practice Consulting entity Data Safety Monitoring Board Health maintenance organization (research department) UnknownF | 36 (9.7) 35 (9.4) 18 (4.9) 15 (4.0) 15 (4.0) 12 (3.2) 11 (3.0) 7 (1.9) 4 (1.1) 1 (0.3) 1 (0.3) 1 (0.3) 268 (72.2) |
Roles respondents have taken on in relation to trial operation
g*
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Professional roles respondents have taken on
h*
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Roles in relation to the trial | n (%)q | Professional roles | n (%)q |
Trial statistician Data Safety Monitoring Board member Trialist or investigator (i.e., co-investigator in a trial) Data analyst Principal investigator (PI) of a clinical trial Sponsor representative Funder representative Data manager Steering Committee Independent unblinded reporting Statistician to the DSMB Trial coordinator Data coordinator/manager Government regulator Consultant Unknown G | 161 (43.4) 136 (36.7) 88 (23.7) 68 (18.3) 30 (8.1) 26 (7.0) 18 (4.9) 11 (3.0) 11 (3.0) 9 (2.4) 7 (1.9) 4 (1.1) 3 (0.8) 3 (0.8) 171 (46.1) | Methodological scientist/research methodologist Epidemiologist Mathematician/statistician Data manager Computer programmer Research or clinical trial coordinator Computer scientist Ethics specialist Physician Information technologist Lawyer Medical laboratory technician Medical laboratory scientist Nurse or nurse practitioner Biochemist Engineer Regulator Teacher Therapist Trial management UnknownH | 89 (24.0) 63 (17.0) 48 (12.9) 36 (9.7) 35 (9.4) 12 (3.2) 10 (2.7) 10 (2.7) 9 (2.4) 6 (1.6) 2 (0.5) 1 (0.3) 1 (0.3) 1 (0.3) 1 (0.3) 1 (0.3) 1 (0.3) 1 (0.3) 1 (0.3) 1 (0.3) 211 (56.9) |
Main results for questions 1 to 4
Interim Combined Event Rate
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1 a) During an ongoing Randomized Controlled Trial (RCT), do you think that the Data Safety Monitoring Board (DSMB) for an RCT should share the Interim Combined Event Rate with ANY of the following parties? | |
Response | Results (n; % [95% CI]), N = 262 |
Yes | 168; 64.1% [58.0% to 69.9%]; |
With whom?*
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B. The Steering Committee A. The Sponsor C. The Investigator(s) D. The Funder(s) E. Other, Please Specify: • Institutional Review Board or Research Ethics Boards, • Regulatory Bodies, • Blinded Statistician on Steering Committee, • Study Statistician • Participants • Professional public | 142; 54.2% [48.2% to 60.2%]; 101; 38.5% [32.7% to 44.4%]; 80; 30.5% [25.0% to 36.1%]; 64; 24.4% [19.2% to 29.6%]; 15; 5.7% [2.9% to 8.5%]; |
No (F. None of the Above) | 94; 35.9% [30.1% to 41.7%] |
1 b) How useful is it to share the Interim Combined Event Rates at interim? (On a scale from 0 to 10 where 0 is Not Useful at All and 10 is Very Useful) Question 1 b. answered only by those who answered A, B, C, D or E to Question 1 a. | |
Results (Mean [95% CI]; Median [IQR]), N = 146 | |
6.97 [6.62 to 7.31]; 7 [6-8] | |
Interim Control Event Rate
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2 a) During an ongoing Randomized Controlled Trial (RCT), do you think that the Data Safety Monitoring Board (DSMB) for an RCT should share the Interim Control Event Rate with ANY of the following parties? | |
Response | Results (n; % [95% CI]), N = 237 |
Yes | 88; 37.1% [31.0% to 43.3%] |
With whom?*
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B. The Steering Committee C. The Investigator(s) A. The Sponsor D. The Funder(s) E. Other, Please Specify: • Institutional Review Board or Research Ethics Boards, • Regulatory Bodies • Professional Public • Study Statistician | 60; 25.3% [19.8% to 30.9%] 35; 14.8% [10.3% to 19.3%] 33; 13.9% [9.5% to 18.3%] 30; 12.7% [8.4% to 16.9%] 22; 9.3% [5.6% to 13.0%] |
No (F. None of the Above) | 149; 62.9% [56.7% to 69.0%] |
2 b) How useful is it to share the Interim Control Event Rates at interim? (On a scale from 0 to 10 where 0 is Not Useful at All and 10 is Very Useful) Question 2 b. answered only by those who answered A, B, C, D or E to Question 2 a. | |
Results (Mean [95% CI]; Median [IQR]), N = 72 | |
7.03 [6.55 to 7.50]; 7 [5-8] | |
Adaptive Conditional Power
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3 a) During an ongoing Randomized Controlled Trial (RCT), do you think that the Data Safety Monitoring Board (DSMB) for an RCT should share the Adaptive Conditional Power with ANY of the following parties | |
Response | Results (n; % [95% CI]), N = 224 |
Yes | 80; 35.7% [29.4% to 42.0%] |
With whom?*
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B. The Steering Committee A. The Sponsor C. The Investigator(s) D. The Funder(s) E. Other, Please Specify • Trial statistician, • Pre-specified members of the sponsor and steering committee, • Professional public, • Institutional Review Board or Research Ethics Boards | 45; 20.1% [14.8% to 25.3%] 34; 15.2% [10.5% to 19.9%] 27; 12.1% [7.8% to 16.3%] 22; 9.8% [5.9% to 13.7%] 21; 9.4% [5.6% to 13.2%] |
No (F. None of the Above) | 144; 64.3% [58.0% to 70.6%] |
3 b) How useful is it to share the Adaptive Conditional Power at interim? (On a scale from 0 to 10 where 0 is Not Useful at All and 10 is Very Useful) Question 3 b. answered only by those who answered A, B, C, D or E to Question 3 a. | |
Results (Mean [95% CI]; Median [IQR]), N = 66 | |
6.64 [6.08 to 7.20]; 7 [5-8] | |
Unconditional Conditional Power
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4 a) During an ongoing Randomized Controlled Trial (RCT), do you think that the Data Safety Monitoring Board (DSMB) for an RCT should share the Unconditional Conditional Power with ANY of the following parties? | |
Response | Results (n; % [95% CI]), N = 208 |
Yes | 82; 39.4% [32.8% to 46.1%] |
With whom?*
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B. The Steering Committee A. The Sponsor C. The Investigator(s) D. The Funder(s)* E. Other, Please Specify • Pre-specified with whom such as selected members of the sponsor or funder who do not see patients • Study statistician • Steering committee • Professional public • Institutional Review Board or Research Ethics Boards | 57; 27.4% [21.3% to 33.5%] 42; 20.2% [14.7% to 25.6%] 30; 14.4% [9.6% to 19.2%] 29; 13.9% [9.2% to 18.6%] 17; 8.2% [4.4% to 11.9%] |
No (F. None of the Above) | 126; 60.6% [53.9% to 67.2%] |
4 b) How useful is it to share the Unconditional Conditional Power at interim? (On a scale from 0 to 10 where 0 is Not Useful at All and 10 is Very Useful) Question 4 b. answered only by those who answered A, B, C, D or E to Question 4 a | |
Results (Mean [95% CI]; Median [IQR]), N = 67 | |
6.64 [6.08 to 7.20]; 7 [5-8] |
Interim Combined Event Rate (ICombinedER)
Interim Control Event Rate (IControlER)
Adaptive Conditional Power (ACP)
Unconditional Conditional Power (UCP)
Sharing other kinds of information
Do you think that any other information should be shared during the interim of a randomized controlled trial by the Data Safety Monitoring Board (DSMB)?
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Total responses to question: 210 | ||||
Response
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Count; % [95% CI]
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No | 109; 51.9% [45.0% to 58.8%] | |||
Yes | 101; 48.1% [41.2% to 55.0%] | |||
For those that answered Yes, what other information the DSMB should share at a trial’s interim, with whom it should be shared, why, and how useful it is to share that information?
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What should be shared?
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Count; % [95% CI]
A
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With whom should that information be shared?
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Why should this information be shared?
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Usefulness to share*
mean [95% CI];
median [IQR]
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Information about trial conduct (e.g., protocol adherence, operational issues, enrollment, recruitment, treatment adherence, trial management, data quality and completeness) | 67; 31.9% [25.7% to 38.6%] | • Sponsor, • Steering Committee, • Investigators, or any relevant party | To ensure that the trial is conducted well with integrity and ethically. Information about trial conduct issues will help instigate corrective measures | 9.16 [8.89 to 9.42]; 10 [8–10] |
Safety Issue or concern | 50; 23.8% [18.3% to 30.1%] | • Sponsor • Steering Committee • Investigator(s) • Ethics Committee | Based on the type of safety concern, investigators may need to increase monitoring to protect patient safety, change the trial’s protocol or request new consent from enrolled patients based on new safety risk | 9.35 [9.02 to 9.69]; 10 [9–10] |
DSMB trial recommendations such as stopping or continuing the trial and possible sample size adjustment. Information shared does not include unmasking group information. | 21; 10.0% [6.3% to 14.9%] | • Sponsor • Steering Committee | To protect the trial’s integrity, patient safety, and trial resources. Due diligence to patients and the public good | 9.52 [9.08 to 9.96]; 10 [10–10] |
Overall patient baseline characteristics | 9; 4.3% [2.0% to 8.0%] | • Any relevant party | Help study team understand if their enrollment is targeting the intended population. Protect the generalizability of the study. Help evaluate recruitment procedures and analysis plan | 8.0 [7.27 to 8.73]; 8 [8–8] |
Any relevant data or raw data | 4; 1.9% [0.5% to 4.8%] | • Any relevant party | Sharing allows for broader stakeholder discussion of the benefits of treatment versus the risks of adverse events than just a committee with minimum involvement. There is no harm in this if efficacy stopping rules are pre-specified | 9.33 [8.68 to 9.99]; 9 [9–9.5] |
Important information from outside of the trial that is relevant to the current trial, the enrolled patients, the sponsor and the investigators | 2; 1.0% [0.1% to 3.4%] | • Steering Committee • Study team members | During a long-term trial, results from other trials may affect the ethics, scientific rationale, care of patients and conduct of the current trial | 9.5 [8.52 to 10]; 9.5 [9.25–9.75] |
Sharing of interim information as indicated in encountered DSMB charters by respondents
Have you ever been involved in a trial where it was explicitly stated in the Data Safety Monitoring Board (DSMB) charter
what interim information/data/results should be shared
and
with whom that information should be shared
during the trial’s interim?
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Total responses to question: 207 | |||
Response
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Count; % [95% CI]
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No | 103; 49.8% [42.8% to 56.7%] | ||
Yes | 104; 50.2% [43.3% to 57.2%] | ||
For those that answered “yes” and according to any DSMB charter(s) they encountered, which of the following pieces of interim information
should be shared
during the interim of a trial,
with whom
and
under what circumstance
the sharing would happen.
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Interim Information
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Count; % [95% CI]
B
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With whom should that information be shared?
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Under what circumstance this information should be shared according to the charter? Summary of responses
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Interim Combined Event Rate | 55; 26.6% [20.7% to 33.1%] | Various parties indicated: • Sponsor • Investigator • Funder • Steering Committee • Regulator • Other relevant parties | Various responses were given. Singular parties: • With the investigator: if the overall rate was much lower than hypothesized and if there was a need to adjust the sample size • With the Steering Committee: always shared at each meeting without restrictions. To help with potential sample size re-estimation and re-assess power without unmasking group event rates. When the overall rate is much lower than anticipated • With the sponsor: shared during open session report. To help with potential sample size re-estimation. Help sponsor anticipate the length of the trial. Sharing was up to the DSMB’s discretion • With the regulatory agency: If there was a safety issue A combination of parties: • With select members of the sponsor, steering committee or investigator(s): pre-specified in the charter. When benchmarks are not met or when there is determined need for a sample size re-estimation. Need to share if there was a recommendation from the DSMB to stop the trial because of futility or efficacy. Such information is only used for internal decision-making and is not for publication or further dissemination • With the sponsor, funder or investigator(s): once accrual was complete and the primary outcome was known for at least a certain set percentage of those enrolled. It was also indicated that this information was shared at every planned interim look • With relevant parties: for safety and ethical issues |
Interim Control Event Rate | 16; 7.7% [4.5% to 12.2%] | Various parties indicated: • Sponsor • Investigator • Funder • Steering Committee • Regulator • Other relevant parties | Various responses were given. Singular parties: • With the Steering Committee: pre-specified in the charter. If the event rate was different from what was pre-specified in the protocol • With the sponsor: when there is a futility analysis and if the interim control event rate differed majorly from the design assumptions • With the regulatory agency: if there was a safety issue A combination of parties: • Select members of sponsor/funder, Steering Committee or investigator(s): o Pre-specified in the charter. sharing this information was not data driven o It would be shared once accrual was complete and the primary outcome was known for at least a certain set percentage of those enrolled. It was also indicated in another instance that interim control event rate was shared at every planned interim look • With relevant parties: For safety and ethical issues |
Adaptive Conditional Power | 19; 9.2% [5.6% to 13.9%] | Various parties indicated: • Sponsor • Investigator • Funder • Steering Committee • Other relevant parties | Various responses were given. Singular parties: • With the sponsor: would be shared at interim at the time of formal futility analysis • With the Steering Committee: would be shared at interim at the time of formal futility analysis and when a boundary was crossed. Also shared when there was a need for a management decision to be made A combination of parties: • Select members of sponsor/funder, Steering Committee or investigator(s): if the adaptive conditional power falls below a pre-fixed level or when there was data supporting stopping the trial. Pre-specified in the charter. Such information is only used for internal decision-making and is not for publication or further dissemination. In one instance it was also shared at the annual meeting report • With relevant parties: for safety and ethical issues |
Unconditional Conditional Power | 18; 8.7% [5.3% to 13.4%] | Various parties indicated: • Sponsor • Investigator • Funder • Steering Committee • Regulator • Other relevant parties | Various responses were given. Singular parties: • With the sponsor: would be shared at interim at the time of formal futility analysis and for a needed sample size recalculation • With the Steering Committee: would be shared at interim when there was a clear benefit or harm to whatever was being investigated and to re-assess power without unmasking interim results A combination of parties: • With select members of sponsor/funder, Steering Committee or investigator(s): pre-specified in the charter. When there was data supporting stopping the trial • With relevant parties: for safety and ethical issues There was an argument that such information is implicitly available, even if it is not directly provided |
Other information | |||
Information about trial conduct | 21; 10.1% [6.4 to 15.1%] | Various parties indicated: • Sponsor • Investigator • Funder • Steering Committee • Regulator | A combination of parties: • With the sponsor/funder, Steering Committee, investigator(s) or regulator if needed: This is not confidential information and should be shared during DSMB open sessions according to the charter with any relevant party at the open session and those responsible for the conduct of the trial to ensure the integrity of the trial’s conduct and correct problems as soon as possible |
Safety issue or concern | 16; 7.7% [4.5% to 12.2%] | Various parties indicated: • Sponsor • Investigator • Funder • Steering Committee • Regulator | A combination of parties: • With the sponsor/funder, Steering Committee, investigator(s) or regulator if needed: This is not confidential information and should be shared during DSMB open sessions according to the charter with any relevant party at the open session and those responsible for the conduct of the trial. It is important to share this information to help those responsible for the trial’s conduct to ensure participant safety |
DSMB trial recommendations such as stopping or continuing the trial and possible sample size adjustment. | 15; 7.2% [4.1% to 11.7%] | Various parties indicated: • Sponsor • Steering Committee | A combination of parties: • With the Steering Committee or sponsor: Pre-specified in the charter. Typical information shared in this circumstance would not include unmasked group information. However, it was indicated that if there cases where unmasked information would be shared if the decision to stop the trial has been made (e.g., for futility, efficacy or if some other pre-specified boundary has been reached) |
Overall patient baseline characteristics | 3; 1.4% [0.3% to 4.2%] | Various parties indicated: • Sponsor • Investigator • Funder • Steering Committee • Regulator | A combination of parties: • Sponsor/funder, Steering Committee, investigator(s) or regulator if needed: this is not confidential information would be shared during DSMB open sessions according to the charter with any relevant party at the open session and those responsible for the conduct of the trial |
Unmasked treatment arm information | 1; 0.5% [0.01% to 2.7%] | Various parties indicated: • Sponsor • Investigator • Public | A combination of parties: • With the sponsor, investigator(s) or public: it was also mentioned that primary outcome data by treatment group was once shared with the sponsor, investigator or public if the primary outcome is known for at least set percentage of trial patients and the target sample size was enrolled |