On the use of RWD in support of regulatory submission in drug development.

For the approval of a drug product, the United States Food and Drug Administration requires substantial evidence (SE) regarding effectiveness and safety of the test drug to be provided. In recent years, the use of real-world data in support of regulatory submission of pharmaceutical development has received much attention, and real-world evidence (RWE) is treated as complementary to SE by evaluating the real-world performance of the test treatment. In this article, we start by summarizing current regulatory perspectives on drug evaluation and some potential challenges in using RWE. To test for superiority in co-primary endpoints, a two-stage hybrid RCT/RWS adaptive design that combines randomized control trial for providing SE and real-world study for generating RWE is proposed. We use superiority in effectiveness and non-inferiority in safety as an example to illustrate how to implement this design. Numerical studies have shown that the proposed design has merits in reducing the required sample size compared with traditional co-primary endpoint tests while maintaining statistical power and controlling type I error inflation. The proposed design can be implemented in drug development considering co-primary endpoints, especially for oncology and rare disease drug development.

Innovative design and analysis for rare disease drug development.

One of the most challenges for rare diseases drug development is probably the availability of subjects with the diseases under a small patient population. It is then a great concern how to conduct clinical trials with the limited number of subjects available for obtaining substantial evidence regarding effectiveness and safety for approval of the drug product under investigation. For rare diseases drug development, FDA indicated that the Agency does not have the intention to create a statutory standard for approval of orphan drugs that is different from the standard for approval of drugs in common conditions. In this case, innovative thinking and approach for obtaining substantial evidence for approval of rare diseases drug products are necessarily applied. In this article, basic considerations for rare disease drug development are discussed. The innovative thinking of demonstrating not-ineffectiveness rather than effectiveness with a limited number of subjects available is outlined. In addition, an innovative approach utilizing a two-stage adaptive seamless trial design in conjunction with the concept of real-world data and real-world evidence is proposed not only to obtain substantial evidence for approval of rare diseases drug products, but also to meet the same standard as those drug products in common conditions. Under the two-stage adaptive seamless trial design, sample size calculation for rare diseases clinical trials based on the innovative probability monitoring procedure is also discussed.

Statistical considerations for rare diseases drug development.

One of the most challenges for rare disease clinical trials is probably the availability of a small patient population. It is then a great concern on how to conduct clinical trials with a small number of subjects available for obtaining substantial evidence regarding safety and effectiveness for approval of the rare disease drug product under investigation. FDA, however, does not have the intention to create a statutory standard for approval of orphan drugs that are different from the standard for approval of drugs in common conditions. Thus, it is suggested that innovative trial designs such as a complete n-of-1 trial design or an adaptive design should be used for an accurate and reliable assessment of rare disease drug products under investigation. In this article, basic considerations, innovative trial designs, and statistical methods for data analysis are discussed. In addition, some innovative thinking for the evaluation of rare disease drug products is proposed.

Clinical trial evidence supporting FDA approval of novel orphan drugs between 2017 and 2023.

Characterization analysis of 87 pivotal clinical trials for 72 novel orphan drugs (76 orphan indications) approved by the FDA from 2017 to 2023 revealed that the clinical trial evidence supporting FDA orphan drug approvals often lacked high-quality designs, which frequently did not incorporate randomization, blinding, placebo or no treatment control, or clinical endpoint-driven methodologies. Additionally, regulatory flexibility was observed in the quantity of clinical trial evidence required, which included choices such as a single trial plus confirmatory evidence, one large multicenter trial or at least two trials. Furthermore, the overall strength of the clinical trial evidence exhibited variations across different orphan drugs and indications, influenced by features such as the therapeutic area and whether the orphan drug was granted accelerated approvals.

The use of real-world data/evidence in regulatory submissions.

The 21st Century Cures Act passed by the United States (US) Congress in December 2016 requires the US Food and Drug Administration (FDA) shall establish a program to evaluate the potential use of real-world evidence (RWE) which is generated from real-world data (RWD) to (i) support approval of new indication for a drug approved under section 505 (c) and (ii) satisfy post-approval study requirements. RWE offers the opportunities to develop robust evidence using high-quality data and sophisticated methods for producing causal-effect estimates regardless randomization is feasible. In this article, we have demonstrated that the assessment of treatment effect (RWE) based on RWD could be biased due to the potential selection and information biases of RWD. Although fit-for-purpose RWE may meet regulatory standards under certain assumptions, it is not the same as substantial evidence (current regulatory standard in support of approval of regulatory submission). In practice, it is then suggested that when there are gaps between fit-for-purpose RWE and substantial evidence, we should make efforts to fill these gaps based on a comprehensive evaluation of the treatment effect. We also review two RWE examples to show some potential use of RWE in clinical studies.

Single-Study Approvals: Quantum of Evidence Required.

When does a single positive adequate and well-controlled study of a new drug meet the statutory requirement to demonstrate substantial evidence of effectiveness? The answer to this question, particularly with respect to new molecular entities, has been of considerable debate since 1962 when the requirement that new drugs prove their benefit to patients became law. A 1997 revision to the statute provided one pathway to a single-study approval (a single adequate and well-controlled study plus confirmatory evidence), while a 1998 guidance issued by FDA provided additional pathways, one of which is the one that is most frequently cited by FDA (a single statistically very persuasive study). This paper explains these 2 distinct pathways and provides illustrative examples of how FDA uses each of these 2 pathways. Regulators, industry, patients, and investors should each find this exegesis of these 2 independent, yet equally viable and valuable, pathways to an FDA approval both illuminating and invaluable.

Single-Study Approvals: Quantum of Evidence Required.

When does a single positive adequate and well-controlled study of a new drug meet the statutory requirement to demonstrate substantial evidence of effectiveness? The answer to this question, particularly with respect to new molecular entities, has been of considerable debate since 1962 when the requirement that new drugs prove their benefit to patients became law. A 1997 revision to the statute provided one pathway to a single-study approval (a single adequate and well-controlled study plus confirmatory evidence), while a 1998 guidance issued by FDA provided additional pathways, one of which is the one that is most frequently cited by FDA (a single statistically very persuasive study). This paper explains these 2 distinct pathways and provides illustrative examples of how FDA uses each of these 2 pathways. Regulators, industry, patients, and investors should each find this exegesis of these 2 independent, yet equally viable and valuable, pathways to an FDA approval both illuminating and invaluable.