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Four Considerations for Every Rare Disease Development Program: Summary of CBI’s Rare Disease Clinical Development and Access Summit

Posted by Meagan Spychala & Karl Whitney on Thu, Jan 23, 2020 @ 09:17 AM
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Rho representatives joined regulators, industry scientists, and numerous patient-advocacy groups at CBI’s Rare Disease Clinical Development and Access Summit in Washington this past December. Attendees were able to share best practices in product development for rare disease programs in formal presentations and through informal networking. The following are 4 considerations for your development program that were highlighted during the conference.

1)  Seek early engagement for patient and caregiver perspectives and with key  payers.
Sponsors need patient and caregiver perspectives in order to ensure clinical studies are properly designed to provide evidence speaking to issues that truly matter to patients and their caregivers. These interactions should start as early on in the process as possible, even as early as initial animal proof-of-concept stage. Patient advocates advised companies to be open, transparent, and humble in approaching their communities for these insights; patients and caregivers want their perspectives heard and know that increasingly they have great influence in shaping product development for their conditions. Because of this increasing influence, some patient groups are not waiting for outreach from product developers, and have conducted or are planning formal Patient-Focused Drug Development or FDA listening sessions so that the community can proactively shape FDA’s understanding of key concerns Young pretty girl giving the sick woman glass of waterand priorities for product development.

It's also important to engage with key payers such as Centers for Medicare and Medicaid Services (CMS) no later than End of Phase 2 so that the pivotal studies can provide data that will support reimbursement. Often this means exploring persistence of effect in a longer study than might be minimally required by FDA. And, on that note, don't forget the perspectives of payers outside the US, including via the Health Technology Assessment processes in EU member states.

2)  Regulatory authority investment in rare disease development programs means more opportunities for dialog between regulators and sponsors: prepare for and embrace the increased access.
It is useful to note that in all these discussions about the development program, sponsors should make the most of milestone meetings and other opportunities to gain consensus with FDA on your plans. In 2018, 58% of the approvals were for rare disease indications and FDA speakers shared freely about how important and exciting this time is for them, patients, and industry. Precisely because FDA and similar stakeholders are so invested in these programs, and because these programs often include novel or challenging development issues, an iterative process in arriving at agreements should be expected. This will particularly be the case for topics lacking clear precedent owing to the rare nature of the disease in question. Therefore, it is imperative to identify key development questions and discuss them transparently with FDA and in hopes of settling key program questions by End of Phase 2.

3)  Plan early for Chemistry Manufacturing Controls (CMC).
Once your lead is selected, it's critical to provide sufficient resources and advanced planning to the CMC development program. All too often, especially for a program benefiting from enhanced support and guidance from FDA via Breakthrough Therapy or Regenerative medical pills industry  factory and production indoorMedicine Advanced Therapy designations, sponsors find themselves with near-complete clinical programs backed by incomplete CMC packages. Proper planning and support is the only way to ensure nimble scale-up as development proceeds and as the team begins to prepare for marketing. In that light, as much as possible, avoid tweaks to the investigational product to avoid having an even higher hill to climb for the CMC program. By the same token, if the product needs a specialized delivery device, work to settle the design and performance features of this as early as possible to allow the team to focus on other things like running efficient trials. Finally, the same plan-ahead advice likely applies to the nonclinical program. Interested in knowing more about how to plan for your CMC development program? In the near future, another blog post will address this topic, so be on the look-out.                                                                    

4)  Strategize for how to streamline your clinical trials while still supporting your claims.
In rare disease, recruitment and retention for clinical trials can be increasingly difficult due to the small population size. Creating a streamlined program strategy that will support your potential label will assist in a more efficient product development program. If the disease course, genotype, and phenotype are poorly understood, a natural history study is an absolute must to gain valuable information about the disease and potential endpoints that would be of value to your proposed claims. Remember that the first-in-human study may end up being the pivotal study, so it has to be well designed and as flawlessly executed as possible to deliver the best possible data. Perhaps this is easier said than done, but it's a fundamental pillar of successful product development, particularly for rare diseases. Even if your first-in-human study does not become your pivotal, you should look into alternative study designs that can reduce your sample size and discuss with the agency the composition of the program to understand the expectations for that indication and claim.

Topical, targeted industry meetings like this are excellent opportunities to share ideas and best practices in a small setting with a wide range of highly experienced people, which is why Rho staff regularly attend and contribute to such meetings. No meeting can offer a comprehensive view of everything that can come up in your development program or risks and opportunities to consider, which is why having an expert partner can be invaluable to your program. Contact us at any point in your development program for a free expert consultation; you'll be pleased with our team's thoughtful and creative review.

Meagan3-1

Meagan Spychala, PhD, Assistant Vice President of Patient Engagement and Program Strategy at Rho, serves as Rho’s expert on patient-focused clinical research activities and incorporates the patient and caregiver voice and experience into the clinical development program.  She recognizes the uniqueness of each clinical trial, which is especially true within rare disease clinical research, and understands the importance of each patient in the development program.

karlKarl Whitney, PhD., Assistant Vice President of Product Development, leads multiple integrated drug development programs spanning the development spectrum by planning, managing, and overseeing concurrent manufacturing, nonclinical, clinical, and regulatory activities. Dr. Whitney has also contributed to preparation of many regulatory submissions,  clinical protocols and amendments, and numerous other documents. 

 

Current Gene Therapy Landscape:  Overview, Challenges, and Benefits

Posted by Kristin Gabor on Wed, Jan 15, 2020 @ 11:22 AM
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In 2017, the US Food and Drug Administration (FDA) approved its first gene therapy, a chimeric antigen receptor T-cell (CAR-T) product to fight acute lymphoblastic leukemia (Kymriah). That same year, another CAR-T therapy was approved to fight certain types of B-cell lymphoma (Yescarta). Since then, 4 additional products have been approved to treat serious diseases such as B-thalassemia, spinal muscular atrophy, a rare form of vision loss and a rare form of primary immunodeficiency. There are currently over 450 gene therapy and gene-based medicine companies worldwide and around 800 gene therapy and gene-modified cell therapy clinical trials being conducted (ARM Q3 update).

Significant progress has been made in developing safe gene therapy products in recent years. Just over 20 years ago, the tragic case of 19-year old Jesse Gelsinger who died during a gene therapy trial led to a temporary collapse in the gene therapy field. Since then, the gene therapy industry has come a long way. In a joint statement made in January 2019, FDA Commissioner Scott Gottlieb and CBER Director Peter Marks noted that based on an assessment of the current pipeline and clinical success rates of gene therapy products, the FDA anticipates that by 2020 they will be receiving more than 200 INDs per year for cell-based or directly administered gene therapies and by 2025 the FDA will be approving 10 to 20 cell and gene therapy products a year.

The basics – what is gene therapy?kristin1

Gene mutations can be inherited or occur as cells age or become exposed to certain chemicals. Small changes to our genetic material can have large impacts on cellular function.

Gene therapy products mediate their effect by transfer of genes or alteration of human genetic sequences. It can be thought of as the introduction, removal, or change of genetic material within patient cells – for instance, repairing a faulty gene in order to produce new or modified proteins, increase proteins that will fight disease, or reduce proteins that cause disease. This can be achieved by gene replacement, gene silencing, gene addition, or gene editing.

The genetic material is typically transferred into patient cells using a specific type of delivery mechanism (described below). Once inside the cell, the gene will make functional protein or target the disease-causing gene.

Gene Delivery Mechanisms

Gene therapy administration can occur via ex vivo or in vivo mechanisms. With ex vivo gene therapy, targeted cells (eg, chimeric antigen receptors (CAR) T cell therapies, T cell receptor (TCR) therapies) are extracted from the patient and the cells are genetically modified in vitro before they are transferred back into the patient. In vivo administration occurs via direct delivery to the patient using a viral or non-viral vector and the target cells remain in the body of the patient.kristin2

Vectors (carriers of the gene), can come in the form of viral vectors, which are genetically engineered viruses that replace the virus genome with the therapeutic gene. Examples of viral vectors are retroviruses, lentiviruses, and adeno-associated virus (AAV; of note, the AAV method is believed by many to be the future of gene therapy). Plasmids (small DNA circles or “naked” DNA), engineered bacteria, and liposomes are other vectors of gene therapy administration to either carry and deliver a replacement gene or to help or silence an existing gene.

Another type of gene therapy product is genome edited cells, which can be generated using zinc finger nucleases (ZFNs); transcription activator-like effector-based nucleases (TALEN), or nucleases such as Cas9 and Cas12a that derive from the Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR/Cas). For instance, one company is using a genome editing platform called ARCUS derived from a natural genome editing enzyme called a homing endonuclease in their CAR-T development programs.

Challenges and Benefits in Developing Gene Therapies

The unique benefits of gene therapy are that it targets the cause of the disease and has the ability to treat or maybe even cure rare, debilitating diseases that have few to no treatment options, often with a single administration. Over time, the high price tag of gene therapy could reduce or eliminate the need for a lifetime of expensive and/or painful ongoing treatments that many in this patient population would require.

Although gene therapy offers a number of unique benefits, a number of challenges exist that make the development of gene therapies difficult as well as expensive. Those include:

• Length of clinical trial process – long term safety follow up due to uncertainty surrounding the potential durability of effect and long-term safety effects or complications;
• Manufacturing is complex and time intensive, and many sponsors have faced capacity constraints due to the difficulty in mass production (of viral particles, for instance);
• Individual response variability;
• Some conditions have many mutations leading to a given disease and one gene therapy approach may only work for a subset of affected individuals;
• May stabilize disease pathology but not actually reverse existing damage;
• The efficiency of gene transfer with vectors and the limited control over where integrating viral vectors will integrate;
• Dose of vectors may be high and large doses may be needed to reach target tissues; vectors could be filtered out in the liver or cleared by an immune response;
• Unlike other therapeutics, once administered there is no dose titration and no ability to control expression levels; gene therapy cannot be turned on or off. It is also very likely that there is no ability to do repeat dosing due to immunity developed during initial treatment.

An Advancing Field

Gene therapy offers the potential for significant breakthroughs and a lot of exciting progress hBlue DNA helix background-1as been made with scientific advances in gene therapy and the recent FDA approvals. Their complexity to develop should not be underestimated, as evidenced by the FDA’s release of 6 additional guidances in 2018 intended to help product developers. The gene therapy industry is poised for the future, but due to its complexity the development process needs to be thoughtfully planned and managed. Critical to the success of the field will be the capacity to scale up for AAV manufacturing or other gene therapy manufacturing factories and a streamlined regulatory landscape.

Rho Can Help

There are several unique aspects of gene therapy clinical trials. Rho is currently leading several gene therapy studies and has conducted over 20 gene/cellular therapy trials in over 1000 patients.  One of our sponsors commented, “Our collaborative relationship with Rho has been instrumental in the implementation of a complex and rigorous first in human genetic medicine study, including strategic solutions for unique challenges faced in rare disease gene therapy trials.  Rho has leveraged existing relationships with patient advocacy organizations and worked closely with a centralized biosafety review partner early in study startup to help identify and mitigate potential challenges. “   

From both a clinical and regulatory standpoint, our experts can offer advice on your gene therapy trial from the preclinical phase through post-submission. For additional gene therapy considerations from our experts, please view our webinar, "Development Advice for Gene Therapy Products"  and for regulatory considerations,  David Shoemaker's article, "The Gene Therapy Product Development Process."

Need support designing and executing your next gene therapy trial? Ask our experts for help.

Kristin Gabor smallKristin Gabor, PhD, RAC, Research Scientist, has experience in both regulatory submissions and clinical operations management, with over 10 years of experience in scientific writing and editing clinical and nonclinical documents, which includes numerous publications in peer-reviewed scientific journals.  Dr. Gabor has led and participated in the authoring, review, and preparation of several regulatory and clinical documents, including protocols, clinical study reports, annual safety reports, modules of regulatory submissions (NDA, IND, etc.), and other regulatory documents in a variety of therapeutic areas at various stages of integrated product development programs. Her experience spans a spectrum of therapeutic areas, including cystic fibrosis, sickle cell disease, inflammation and immunology, infectious diseases, atopic dermatitis, multiple sclerosis, and rare diseases. Dr. Gabor earned an interdisciplinary PhD in Functional Genomics from the University of Maine and subsequently received an Intramural Research Training award from the NIH/NIEHS for her postdoctoral studies investigating the role of cholesterol metabolism and cell membrane perturbations in regulating the innate immune response in a rare genetic disease.  Dr. Gabor received her Regulatory Affairs Certification from the Regulatory Affairs Professionals Society (RAPS) in 2018 and is a current member of RAPS and the North Carolina Regulatory Affairs Forum (NCRAF).

 

Update from the top: FDA’s Office of New Drugs ongoing reorganization process

Posted by Karl Whitney on Thu, Jan 02, 2020 @ 11:00 AM
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karlKarl Whitney, PhD, RAC, Assistant Vice President of Product Development, leads multiple integrated drug development programs spanning the development spectrum by planning, managing, and overseeing concurrent manufacturing, nonclinical, clinical, and regulatory activities.

Rho representatives joined regulators, industry scientists, and numerous patient-advocacy groups at CBI's Rare Disease Clinical Development & Access conference in Washington 03-04DEC 2019. During an opening plenary session, FDA's Office of New Drugs (OND) director Dr. Peter Stein shared comments and took questions from the audience. Participants asked a number of questions that indicate a high degree of interest in (and, perhaps, some anxiety about) OND's ongoing reorganization in general and as it might affect specific current projects at the IND or NDA review stage. This reorganization was announced earlier in 2019 and will, among other things, increase the number of offices overseeing review divisions from 6 to 8, and split and/or redesign review divisions to increase the number of divisions from 19 to 27. The reorganization is being implemented in four phases, with the last set to complete by February 2020. Dr. Stein certainly attempted to address some of the audience's concerns. His key message: the ongoing reorganization is intended to improve review processes while ensuring continuity for individual projects. In short, FDA doesn't want to fix what ain't broke.

Instead, the overall goals are to establish more therapeutically aligned, integrated review teams that take an interdisciplinary and 'problem-focused' approach to reviews; and to modernize and standardize review processes across divisions. In the process, he and hOptimization - Business Concept. Golden Compass Needle on a Black Field Pointing to the Word Optimization. 3D Render.is team are taking great care to ensure OND operates smoothly, and that review teams have a re-energized scientific focus for their work.

On the former, he hopes the reorganization will make for more sensible Division groupings. Some large divisions such as Neurology or GI/inborn errors are being split up so that Division Leadership can spend more time on the science and be more externally facing  (eg, at conferences). Individual review teams are being kept together as much as possible when these new divisional groupings are being designed. Further, he has instructed Division heads overall to avoid revisiting prior agreements made between the sponsor and the review team if the team has moved divisions. He believes strongly that it's in nobody's interest to upend established agreements, though he reminded the audience that of course, FDA reserves the right to update its positions as new data accrue. So, sponsor caveat emptor.

On the latter, OND is trying to enhance reviewer consistency and throughput by using a new review template and improved processes that support efficient, integrated reviews of submissions from IND through to approval/post-approval. In addition, a new non-review office called Office of New Drug Policy has been established to support review teams when novel Orange Business Processes Button on Computer Keyboard. Internet Concept.issues come up that lack clear guiding precedent, so that review teams across the OND approach novel issues with greater consistency. Another new cross-cutting office of interest to conference attendees is the planned Division of Rare Disease and Medical Genetics within the new Office of Rare Diseases, Pediatrics, Urologic and Reproductive Medicine. This group will not have direct review responsibilities but rather will offer 'consultative support' to help review teams properly exercise 'flexibility' in product development programs for example in terms of expected safety database size, a topic that commonly arises, naturally, with rare disease development programs. These rare-disease sponsor projects will still be overseen by the Division that makes the most sense from a therapeutic area - for example, Division of Anti-infectives. The new Division of Rare Disease and Medical Genetics group will also have a mandate to engage outside FDA with patient groups, other regulatory bodies, academia, and even Advisory Committees to ensure they understand realities for rare disease product development. One can only speculate as to why these new responsibilities were not assigned to the longstanding Office of Orphan Product Development.

Overall, the audience took a wait-and-see approach insofar as the reorganization is ongoing and the chips haven't fallen yet. Time will tell if the major goals of the reorganization are achieved by this structure, but Dr. Stein certainly made his best case for the various rationales for the temporary upheaval. Maybe spring cleaning came a bit early to the OND this year....

 

Is a Target Product Profile Worth the Effort?

Posted by David Shoemaker on Wed, Dec 18, 2019 @ 09:32 AM
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David Shoemaker, PhD, SVP R&D, has over 25 years of experience in pharmaceutical product development. He has served as a Program Leader or Advisor for multi-disciplinary program teams and has been involved with ensuring products meet regulatory standards at all stages of the development process.

A recent study by the MIT Sloan School of Management determined only 14 percent of clinical studies succeed, indicating there is room for vast improvement in the pharmaceutical industry’s ability to develop needed therapeutics more efficiently1. Inasmuch as the clinical develop program for a product comprises several to dozens of clinical studies to achieve marketing approval, chances are that one or more studies will fail during development. Coincidentally, this success rate of 14 percent approximates the age-old estimate that 10 to 20 percent of products that enter human studies make it to the market2,3. However, an eventual failure rate of 80 to 90 percent for products entering Phase 1 speaks to more than simply clinical study failure rate. The failure rate indicates an overall development process shortcoming that begins during the preclinical stage and destines product development programs for failure. This is due in part to the fact that companies are in many cases not doing the correct clinical study on an efficient path to marketing a needed therapeutic product. They do not possess a road map for success.

As a contract research organization who works extensively with late stage development companies collaborating on the preparation of their marketing applications, Rho continually observes product sponsors who fail during late stage development due to preventable missteps with their product development program. We are always buoyed by starting a new relationship with a company who has taken the time to prepare a Target Product Profile (TPP) because we know we have a client who understands the importance that prescribing information and market position play in the ultimate approval of a product by the regulatory authorities and the commensurate successful market capture. Simply achieving marketing approval is not the goal. The goal is to provide a useful therapy that will meet the needs of patients, physicians, and payers and hopefully advance current therapeutic options. The TPP provides a road map for development of a product, laying out all the key development performance criteria that the investigational product must meet in order to ultimately become the useful therapy the sponsor wants it to be; failure to meet any of these key criteria means the investigational product will not succeed as a useful marketed product and development should be abandoned or somehow re-engineered.

The crafting of a TPP is enabled by a detailed understanding of not only the disease and its associated market, but also unmet patient, physician and payer needs. The goal posts for each of the stakeholders need to be determined by identifying the minimal and the optimal characteristics for a variety of TPP elements. The major criteria to meet patients’ needs reside primarily in efficacy and safety elements, but satisfying dosage, route of administration, and specific patient reported outcomes also must be considered. Obviously physicians’ primary needs will be met if the patients are satisfied but there may be additional considerations regarding route of administration as well as ease and efficiency of therapy. Payer value is derived from beneficial differentiation of efficacy and safety but there may also be differential market forces to consider based on geographical regions (e.g., free market, US; clinical effectiveness, France and Germany; cost effectiveness, UK and Canada). If it becomes clear at any point in development that you will fail to meet the minimal criteria for your product to satisfy any one of these stakeholders’ regulatory or commercial requirements, a company is well advised to abandon development. Also, it is simply common sense for companies to Data analysis chart and graphs-2identify their principal competitive product on the market as well as potential competitive products in development prior beginning their development program in earnest. A comprehensive TPP should contain all of these elements.

The organization of the TPP is understandably varied across the industry with some people using the US Prescribing Information as a template and others adopting the European Summary of Product Characteristics. The FDA even issued guidance back in 2007 advocating the use of the US Prescribing Information organization (https://www.fda.gov/media/72566/download). The advantages of these strategies include the fact that you are effectively preparing your US annotated package insert during your development plan. These documents help both with minimizing and focusing development activities and organizing your marketing application, and they are in a format optimal for discussions with regulators. However, a complete TPP should still include an independent payer assessment that is of no interest to regulators. Other companies prefer more general categories than are found in product labeling such as efficacy, safety, payer value, dosage, indication, population and juxtapose these elements with the attributes of their target competitive product for a more commercially oriented TPP. This allows one to easily see when your product comes up short against a competitor thereby rendering a course correction or a No Go decision.

By focusing both the developmental and marketing goals in the TPP at the preclinical stage a company is able to build a commercial differentiation strategy into their early development plan. Preclinical studies are a lot less expensive to conduct than clinical studies and hypotheses can be tested versus competitive products efficiently. These preclinical experiments may or may not lead to earlier examination of active comparator studies in the clinic. However, it will most certainly enforce the understanding that validating a novel mechanism of action is less important than clinical differentiation from a competitive product. These experiments may allow a company to distinguish between competitors and identify the key competitive product to compete against. Demonstrating proof of concept in no way guarantees profit on return, so it is imperative that companies explore pharmacodynamic activity versus competitive products in their preclinical development programs.

A common reason small or inexperienced companies do not prepare a TPP is the proposed cost and amount of time that must be devoted to its preparation. Companies with an exit strategy at proof of concept or prior to phase 3 often claim the cost is not justifiable. However, the value created by a well-run development program that checks all the boxes for an intelligent investor is worth much more than the cost invested in the preparation of the TPP. Investment firms and big pharma are primarily looking for investments where the risks have been minimized and a program that has been conducted efficiently focusing on the ultimate appropriate indication and patient population while examining carefully the commercial landscape holds enormous value.

Perhaps the greatest value of the TPP is as a communication tool. The ultimate goal of the communications-networkdevelopment program is shared clearly and continually with all the company disciplines, e.g., clinical, preclinical, chemistry manufacturing and controls, regulatory, and marketing. The TPP is also able to be used as an external communication tool that facilitates interactions with regulatory authorities, investors, and the media. The document can be used to help structure regulatory and investor briefing documents as well as press releases. The TPP’s additional use as a communication tool is as an educational document for new team members whether they are within the company or at regulatory authorities.

The bottom line is, you must prepare a TPP early and revise it continually during development if you wish to bring a successful therapeutic to market to advance patient treatment or you are left relying on nothing more than good fortune.

1 Wong, C.H, Siah, K.W., and Lo, A.W. Biostatistics. 2019; 20(2): 273 – 286.
2 https://www.reuters.com/article/us-pharmaceuticals-success/success-rates-for-experimental-drugs-falls-study-idUSTRE71D2U920110214
3 https://www.policymed.com/2014/12/a-tough-road-cost-to-develop-one-new-drug-is-26-billion-approval-rate-for-drugs-entering-clinical-de.html

 

Orphan Drugs and Single Trials

Posted by Joseph Watson on Thu, Dec 12, 2019 @ 09:00 AM
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Joseph Watson, PhD, RAC, Research Scientist at Rho, has experience in both regulatory submissions and clinical document preparation, with over fifteen years of experience in scientific writing and editing jwatsonclinical and nonclinical documents, including numerous publications in peer-reviewed journals.  Dr. Watson has led the preparation, review, and coordination of a variety of regulatory and clinical documents, including protocols; clinical study reports; integrated summaries of biopharmaceutics, safety, and efficacy; CMC and nonclinical documents; draft product labels; and 120‑day safety updates.  His writing and editing experience covers a broad range of therapeutic areas, including drug addiction, middle ear disorders, infectious diseases, psychiatric disorders, acute and chronic pain, multiple sclerosis, hemophilia, and oncology. 

Since the enactment of the Orphan Drug Act in 1983, the number of orphan drug approvals has risen steadily. In 2018 alone, 34 out of 59 approved novel medications were for orphan diseases. Consistent with the increase in orphan applications reviewed by the Agency, Rho has received an increasing number of sponsor requests for support of programs working towards an orphan drug approval. Our sponsors often think that their product can be approved with support from a single trial, but how realistic is this stance? To better understand when a single trial approval is possible, we look to FDA guidances.Conceptual image with ladder reaching increasing graph-1

In the 1998 Guidance for Industry Providing Clinical Evidence of Effectiveness for Human Drug and Biological Products, FDA spells out the potential circumstances in which a single clinical trial for a novel therapeutic could be sufficient to support an efficacy claim. The guidance states “reliance on only a single study will generally be limited to situations in which a trial has demonstrated a clinically meaningful effect on mortality, irreversible morbidity, or prevention of a disease with potentially serious outcome and confirmation of the result in a second trial would be practically or ethically impossible.”

The key points outlined in the guidance are:

1.   The condition must be serious. If the FDA doesn’t believe the condition is serious, they will not consider a single adequate and well controlled trial for a novel therapy.
2.   A second adequate and well-controlled trial is practically or ethically impossible to conduct. This situation could apply for an orphan indication given limited patient populations (and likely assuming point 1 above).

Both points could apply to an orphan indication; an orphan indication has, by definition, a limited patient population, and many orphan indications are serious. A serious orphan indication falls into the “sweet spot” in which FDA may be willing to show flexibility and accept a single adequate and well-controlled trial.

After considering points 1 and 2 below, FDA must review the single adequate and well controlled trial to determine if it is sufficiently robust and compelling; i.e., does it feature any of 5 characteristics that could make it adequate to support an effectiveness claim (in other words, sufficiently robust & persuasive; FDA’s typical prior to reviewing the data is that the determination will be a review issue):

1.   A large multicenter study
2.   Consistency across study subsets (large trial)
3.   Multiple studies in a single study (e.g., properly designed factorial studies)
4.   Multiple endpoints involving different events (i.e., prospectively identified primary and  secondary endpoints representing different beneficial effects)
5.   Statistically very persuasive findings

For orphan indications, characteristics 1 and 2 are difficult to achieve due to the need for large trials. Characteristic 3 is situational; the example provided by FDA highlights a combination therapy tested as both the combination and as individual parts. Characteristic 4 is typically incorporated into the study designs Rho reviews. Often, this item can be interpreted by sponsors as the “everything but the kitchen sink” approach. In our experience, multiple well thought out, differentiated endpoints can help FDA assess approvability; however, FDA will stress that these endpoints should be independent of each other.

Additionally, FDA will often request that the endpoints be hierarchically ranked; this preserves the overall alpha for the study by preventing companies from fishing for an acceptable endpoint should the primary fail. If the program hits on multiple, well-thought out, agreed upon endpoints, improves significantly on current therapies, and the disease is serious, FDA may consider a single trial appropriate.

Clinical Trial written in search barCharacteristic 5 is likely the most realistic situation orphan drug sponsors can achieve, in spite of the small sample sizes typically observed in orphan trials. Assuming the orphan indication is for a serious indication (as defined above), FDA will at times negotiate with a sponsor those outcomes considered sufficient to support approval with a single clinical trial. Such a strategy should be discussed prospectively with FDA prior to initiating the pivotal trial; assuming FDA agrees with the design, FDA may be willing to consider allowing the filing to proceed if either 1) a highly statistically persuasive and clinically meaningful outcome is achieved or 2) at FDA’s discretion, dependent on FDA’s review of the efficacy data, the severity of the disease, and medical need. In practice, this approach has a high chance of failure, as most companies who work on orphan products move into their pivotal study with either 1) very small proof of concept Phase 1/2 trials that hint at efficacy but are not robust or 2) uncontrolled Phase 2 studies that show efficacy versus natural history data but fail to achieve statistically significant results when conducted as randomized, double-blind studies.

That aside, recently, FDA has taken an active approach for approving products based on a single trial with certain therapeutic paths, particularly anti-infectives. The Limited Population Antibacterial Drug (LPAD) pathway allows antibiotics to be approved and labeled for small populations with unmet needs. As of October 2019, two products have been approved using this pathway with single clinical studies:

•   Arikayce (amikacin liposome inhalation suspension), for the treatment of lung disease caused by a group of bacteria, Mycobacterium avium complex, in a limited population of patients with the disease who do not respond to conventional treatment, approved with a single trial on a surrogate endpoint (sputum conversion); and
•   Pretomanid Tablets in combination with bedaquiline and linezolid for the treatment of a specific type of highly treatment-resistant tuberculosis of the lungs, which was approved with a single trial that showed significant benefit relative to historical controls.

The success of these programs demonstrates FDA’s willingness to be flexible when the benefit can be properly assessed and truly outweighs the risk in a specific patient population. However, companies should be cautious when developing an orphan product. Prospectively planning to properly assess efficacy outcomes in reasonably sized, randomized, double-blind Phase 2 trials will help companies make appropriate go/no go decisions earlier in a product’s life cycle, ultimately helping companies spend less time and money on unapprovable products.