The FDA recently updated guidance for clinical trials & trial design. This update stems from an objective of the 21st Century Cures Act (Cures Act). It includes recommendations for how industry sponsors of pharmaceuticals or biologics should design and conduct clinical trials. The guidance provides a greater explanation of how biologic and oncology trial design can simultaneously evaluate more than one investigational drug.
FDA Guidance
The guidance goes into depth about the clinical research milestones of master protocol design. Data integrity considerations are also mentioned for biomarker co-development and trial statistical analysis. Traditionally, oncology clinical trials are designed to assess multiple investigational drugs at the same time. Clinical data in this type of design is analyzed across multiple cancer types during the same trial to find all sources of patient efficacy and commercial value.
Another primary driver is the CDMO race due to testing multiple drugs and sub-populations under the same protocol. Pharmaceutical consultants like RCA Inc. have witnessed a shortening of client commercialization timelines across the life sciences industry. This directly adds incremental pressure on project sponsors. Clinical teams are being tasked to discover late-stage drug success faster than ever before. Every trial must simultaneously ensure patient safety while producing data that satisfies the regulatory safety and effectiveness.
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Investigational Drugs (IND FDA)
The FDA concisely describes this unique protocol design and clinical trial planning for IND filings and multiple sub-studies. Sub-studies may have separate goals and require aligned efforts across the data science team. For example, collaboration is needed in order to appropriately value multiple investigational drugs. Consideration should be given that therapeutic value may be in one or more disease sub-types in the clinical trial.
With these considerations in mind, the FDA goes on to describe the benefits of a master protocol across the study design. This provides the project sponsor design flexibility via electronic data capture (EDC) in an EDC system (e.g. shared control arm, adaptive designs, centralized data capture).
Clinical Trial Design
This new FDA guidance also provides insights on potential challenges the industry should consider when using master protocols. These unintended consequences can include greater difficulty when assigning detailed adverse events to an investigational drug if numerous products are being investigated across the clinical study.
Any lack of adverse event reporting clarity can impact the safety profile of an investigational drug. This directly makes the clinical analysis for FDA approval more complicated for the regulatory body. Multiple study groups can also increase the overinterpretation of study findings. For example, signs of positive product efficacy for cardiac biomarkers could be different than from cancer biomarkers. Biomarker discovery for one subpopulation could also be identified as false if based a different ad hoc patient group.
Basket Trials
Basket trial design includes assessing an investigational drug blend by including a dose-finding or safety lead-in component. The goal is to identify safe quantities of the combination early in the clinical trial before progressing with an efficacy activity-estimating factor. The FDA proposes therapeutic efficacy for sub-studies within basket trials are constructed as single-arm, activity-estimating trial. The primary endpoint would be recorded as total response rate.
The guidance goes on to elaborate on sub-study objectives, including study rationale for each population. A comprehensive statistical analysis plan (SAP) with reasoning for sample size and unique stopping rules based on ineffectuality should also be included in the program documentation.
Umbrella Trials
A master protocol designed to evaluate multiple drugs is commonly referred to as an umbrella trial. These umbrella trials are often administered as a single drug or as a combination product. Umbrella trials are often a randomized controlled trial to evaluate the mechanism of action of the investigational drug/drugs with a common control arm. Study design for an umbrella trial can include sub-studies based on a patient biomarker or to a separate therapeutic sub-study inside the trial.
Clinical Study Design
As the clinical study focus, the FDA provides a clear understanding of how project sponsors improve the efficiency of master protocols. For example, using a common control arm during an Umbrella Trial has proven to help evaluate multiple drugs simultaneously for a single disease state.
Control Arm
For clinical trials, the FDA now recommends a project sponsor use a common control arm when numerous drugs are evaluated simultaneously in a single illness (e.g. umbrella trials). The FDA guidance elaborates in the use of a control arm be the current standard of care (SOC) so trial results are understandable from the perspective of the biologic and oncology medical community.
Changes in SOC can also take place during the trial because of an FDA approval or the latest scientific data. The Statistical Analysis Plan (SAP) would need to be revised before any data analysis occurs if this is the case.
Novel Drugs
When a project sponsor uses sub-studies to assess two or more investigational drugs, the FDA advocates for providing a thorough scientific motivation for the combination. This includes the clinical trial sponsor defining the Recommended Phase 2 Dose (RP2D). Analysis should include each novel drug and ensuring the appropriate dosage has been identified for each individual drug.
Targeting Biomarkers
The FDA goes on to elaborate on digital biomarkers to help validate the patient selection and recruiting for clinical trials. Biomarkers should be clearly identified based on the intended therapeutic response.
For example, an oncology biomarker for tumor size can help predict the response to the investigational drug. This type of study biomarker might demonstrate how the mechanism of action succeeded or failed. There needs to be a consensus among the clinical study team on how biomarkers are justified. Understanding study measures for showing marker positivity before patients enter the trial is critical.
Data Monitoring
One final important note about the master protocol in the updated FDA guidance describes the independent radiologic review committee. This committee medical research should include blinded tumor-based assessments to provide a charter for the independent data monitoring committee (IDMC).
The IDMC charter would guide the committee through ad hoc trials, such as patient efficacy and drug futility. The IDMC can also recommend clinical trial protocol actions. This often includes changes in sample size or modification of a sub-study based on overwhelming futility or efficacy evidence.