Trial Design & Methodology

Designing Single-Arm Studies for Regulatory Acceptance

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In rare and ultra-rare disease drug development, the small number of eligible patients often precludes the use of traditional randomized controlled trials (RCTs). In these settings, single-arm studies—where all enrolled patients receive the investigational therapy—can serve as a scientifically and ethically justifiable alternative. Regulatory bodies including the FDA, EMA, and PMDA recognize the validity of single-arm designs when supported by robust historical data and clearly defined endpoints.
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Rare and Orphan Disease Trials, Trial Design & Methodology

Handling Missing Data in Rare Disease Clinical Trials

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In rare and ultra-rare disease clinical trials, each data point holds immense value. The limited pool of eligible participants means that even a small proportion of missing data can significantly impact statistical power, data interpretability, and regulatory acceptance. Missing data may arise from various sources including patient dropouts, protocol deviations, missed visits, or uncollected endpoint measurements.
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Rare and Orphan Disease Trials, Trial Design & Methodology

Selecting Appropriate Control Groups in Rare Disease Studies

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In clinical research, the control group serves as a critical comparator to evaluate the safety and efficacy of a new treatment. In the context of rare and ultra-rare diseases, however, selecting an appropriate control group presents unique challenges. With patient populations often numbering in the tens or low hundreds globally, traditional randomized controlled trial (RCT) designs may not be feasible or ethical.
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Rare and Orphan Disease Trials, Trial Design & Methodology

Surrogate Endpoint Validation in Orphan Drug Development

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In the world of rare disease clinical research, traditional clinical endpoints—such as survival or long-term functional improvement—can be impractical due to small patient populations, disease heterogeneity, and long progression timelines. This is where surrogate endpoints come in. These are intermediate or substitute measures used to predict the effect of a treatment on a true clinical outcome.
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Rare and Orphan Disease Trials, Trial Design & Methodology

Multi-Arm, Multi-Stage Designs for Small Patient Populations

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Rare disease clinical trials face persistent challenges—limited patient populations, ethical constraints around control arms, and high uncertainty in treatment effects. In such scenarios, traditional parallel-group designs can be inefficient, slow, and unfeasible. This is where Multi-Arm, Multi-Stage (MAMS) designs provide a significant advantage.
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Rare and Orphan Disease Trials, Trial Design & Methodology

Hybrid Clinical Trial Models for Rare Disease Research

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Rare disease trials often face significant logistical hurdles—patients may live far from trial centers, travel burdens are high, and access to specialized sites is limited. To address these challenges, hybrid clinical trial models are gaining traction. These designs combine the best of both worlds: traditional site visits for critical assessments and decentralized methods (e.g., remote monitoring, telehealth) for improved flexibility and reach.
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Rare and Orphan Disease Trials, Trial Design & Methodology

Determining Optimal Sample Sizes in Rare Disease Studies

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One of the most complex and sensitive decisions in rare disease clinical trials is determining the appropriate sample size. Unlike trials for common diseases where thousands of participants may be enrolled, rare disease studies often struggle to recruit even dozens of patients globally. This scarcity makes traditional power-based calculations difficult to apply directly.
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Rare and Orphan Disease Trials, Trial Design & Methodology

Use of Historical Controls in Rare Disease Regulatory Submissions

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Rare disease clinical trials frequently face recruitment challenges due to small patient populations, ethical concerns with placebo groups, or urgency in life-threatening conditions. In such contexts, historical controls—data from previously treated patients not enrolled in the current trial—can serve as comparators to evaluate investigational therapies.
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Rare and Orphan Disease Trials, Trial Design & Methodology

Implementing Basket Trials in Rare Genetic Disorders

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In the realm of rare and ultra-rare genetic diseases, traditional clinical trial structures often fall short due to limited patient populations and disease heterogeneity. Basket trials provide an innovative solution by testing a single investigational therapy across multiple diseases or indications that share a common genetic mutation or biomarker.
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Rare and Orphan Disease Trials, Trial Design & Methodology

Managing Protocol Amendments in Rare Disease Trials

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Rare disease clinical trials often undergo frequent protocol changes due to the evolving understanding of disease mechanisms, adaptive study designs, small patient populations, and safety considerations. These amendments—whether substantial or administrative—must be carefully managed to maintain regulatory compliance, ethical oversight, and data integrity.
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Rare and Orphan Disease Trials, Trial Design & Methodology