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To understand how my administrative clinical trial data is obtained
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and what it can be used for,
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let's take a look at how trial investigators record data on
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\url{ClinicalTrials.gov}.
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Figure \ref{Fig:Stages} illustrates the process I describe below.
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To understand how my administrative clinical trial data is obtained and what it
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can be used for, let's take a look at how trial investigators record data on
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\url{ClinicalTrials.gov}.
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Figure \ref{Fig:Stages} illustrates the different states that a trial can
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transition between while it is operating.
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These states are defined by the National Library of Medicine with respect to
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clinical trial results
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\cite{usnlm_protocolregistrationdata_2024-06-17}.
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During the Pre-Trial period the trial investigators will design the trial,
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choose primary and secondary objectives,
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and decide on how many participants they need to enroll.
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Once they have decided on these details, they post the trial to \url{ClinicalTrials.com}
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and decide on a date to begin enrolling trial participants.
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If the investigators decide to not continue with the trial before enrolling any participants,
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the trial is marked as ``Withdrawn''.
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On the other hand, if they begin enrolling participants, there are two methods to do so.
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The first is to enter a general ``Recruiting'' state, where patients attempt to enroll.
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The second is to enter an "Enrollment by invitation only" state.
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choose primary and secondary objectives, and decide on how many participants
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they need to enroll.
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Once they have decided on these details, they post the trial to
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\url{ClinicalTrials.com} and decide on a date to begin enrolling trial
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participants.
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If the investigators decide to not continue with the trial before enrolling any
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participants, the trial is marked as ``Withdrawn''.
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If they begin enrolling participants, there are two methods to do so.
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The first is to enter an "Enrollment by invitation only" state where the
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trial operators extend invitations through their own connections to doctors
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and patients they are working with.
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The second is to enter a general ``Recruiting'' state, where participants apply
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to join the trial, and the sponsoring organization may extend invitations as
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before.
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After a trial has enrolled their participants, they Will typically move to an
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"Active, not recruiting" state to inform potential participants that they are
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not recruiting.
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During this time, the trial operators continue monitoring participants for
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adverse events and tracking their disease severity and compliance with treatment.
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Finally, when the investigators have obtained enough data to achieve their primary
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objective, the clinical trial will be closed, and marked as ``Completed'' in
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objective, the clinical trial will be closed and marked as ``Completed'' in
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\url{ClinicalTrials.gov}
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If the trial is closed before achieving the primary objective, the trial is
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marked as ``Terminated'' on
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\url{ClinicalTrials.gov}.
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Trials can be terminated because safety or efficacy evidence suggested it was
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not worth continuing, enrollment rates were too low to achieve the primary
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objective within time and budget contstraints.
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\begin{figure}%[H] %use [H] to fix the figure here.
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\includegraphics[width=\textwidth]{../assets/img/ClinicalTrialStagesAndStatuses}
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@ -49,59 +61,55 @@ marked as ``Terminated'' on
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\label{Fig:Stages}
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\end{figure}
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Note the information we obtain about the trial from the final status:
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``Withdrawn'', ``Terminated'', or ``Completed''.
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Although
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\cite{khmelnitskaya_competitionattritiondrug_2021}
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describes a clinical failure due to safety or efficacy as a
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\textit{scientific} failure, it is better described as a compound failure.
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Discovering that a compound doesn't work as hoped is not a failure but the whole
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purpose of the clinical trials process.
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On the other hand, when a trial terminates early due to reasons
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other than safety or efficacy concerns, the trial operator does not learn
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if the drug is effective or safe.
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This is a knowledge-gathering failure where the trial operator
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did not learn if the drug was effective or not.
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I prefer describing a clinical trial as being terminated for
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\begin{itemize}
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\item Safety or Efficacy concerns
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\item Strategic concerns
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\item Operational concerns.
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\end{itemize}
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Unfortunately it can be difficult to know why a given trial was terminated,
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in spite of the fact that upon termination, trials typically record a
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description of \textit{a single} reason for the clinical trial termination.
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This doesn't necessarily list all the reasons contributing to the trial termination and may not exist for a given trial.
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For example, if a Principle Investigator leaves for another institution
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(terminating the trial), is this decision affected by
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a safety or efficacy concern,
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a new competitor on the market,
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difficulties recruiting participants,
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or a lack of financial support from the study sponsor?
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Estimating the impact of different problems that trials face from these
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low-information, post-hoc signals is insufficient.
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For this reason, I use clinical trial progression to estimate effects.
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\todo{not sure if this is the best place for this.}
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% Note the information we obtain about the trial from the final status:
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% ``Withdrawn'', ``Terminated'', or ``Completed''.
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As a trial goes through the different stages of recruitment, the investigators
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update the records on ClinicalTrials.gov.
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Even though there are only a few times that investigators are required
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to update this information, it tends to be updated somewhat regularly as it is
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a way to communicate with potential enrollees.
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When a trial is first posted, it tends to include information
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When a trial is first posted, it includes information
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such as planned enrollment,
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planned end dates,
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the sites at which it is being conducted,
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the diseases that it is investigating,
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the drugs or other treatments that will be used,
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the experimental arms that will be used,
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and who is sponsoring the trial.
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As enrollment is opened and closed and sites are added or removed,
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investigators will update the status and information
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to help doctors and potential participants understand whether they should apply.
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Unfortunately it can be difficult to know why a given trial was terminated,
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in spite of the fact that upon termination, trials typically record a
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description of \textit{a single} reason for the clinical trial termination.
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This doesn't necessarily list all the reasons contributing to the trial termination and may not exist for a given trial.
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For example, if a Principal Investigator leaves for another institution
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(terminating the trial), is this decision affected by
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a safety or efficacy concern,
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a new competitor on the market,
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difficulties recruiting participants,
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or a lack of financial support from the study sponsor?
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% Estimating the impact of different problems that trials face from these
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% low-information, post-hoc signals is insufficient.
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Because there are many things that contribute to the decision to terminate a
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trial but no way for the results to be described in detail,
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we must use another way to infer the relative impact of operational difficulties.
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Although
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|
\cite{khmelnitskaya_competitionattritiondrug_2021}
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|
describes a clinical failure due to safety or efficacy as a
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\textit{scientific} failure, it is better described as a compound failure.
|
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Discovering that a compound doesn't work as hoped is not a failure but the whole
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purpose of the clinical trials process.
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On the other hand, when a trial terminates early due to reasons
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other than safety or efficacy concerns, the trial operator does not learn
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if the drug is effective or safe.
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This is a knowledge-gathering failure.
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I prefer describing a clinical trial as being terminated for
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Safety or Efficacy concerns, Strategic concerns, or Operational concerns
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% -
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% -
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