BADRI RENGARAJAN: You work in the FDA’s Office of Orphan Products Development. What is the Office’s mandate, and what is its relationship with the rest of the FDA?
FDA: The Office was created over 30 years ago. At that time, there was very little focus on developing products for rare diseases. The primary mission of the Office is to promote the development of products for rare diseases. Prior to the passage of the Orphan Drug Act, companies did not have enough incentives to develop products for the rare disease space. The Orphan Drug Act was created to provide those incentives, including a designation and grants program. Our office administers these programs. We are not in the review divisions of the FDA that review marketing applications [i.e., applications that seek approval to market a drug], however, we work closely with them.
FDA: We deal with companies early on. We review products for purposes of orphan designation. There is a corollary designation program for devices. We also have two grants programs to stimulate research for rare diseases and pediatrics – the Orphan Products Grants Program and the Pediatric Devices Consortia Grants Program. Rare diseases have become a focus internally and externally, so, in addition to administering the designations and grants programs, we also serve as a cross-cutting function among all different parts of Agency. We encourage collaboration.
FDA: In addition, we are often the first stop for patients with rare diseases.
BR: It seems to be common wisdom that pharmaceutical companies do not develop drugs for orphan or rare diseases because the revenue opportunity is not attractive (due to small market)? Is the common wisdom correct? Why or why not?
FDA: This wisdom has evolved over time. When the Orphan Drug Act was initially passed, this was the case. Even after the Act was initially passed, we did not see a whole lot of designations come through. But this has changed over time.
Trial costs are rising, and exclusivity has been a good incentive. These days companies will generally see a return on their investment. The rare disease area is becoming a more attractive space – not just for small biotechnology companies but also for large pharmaceutical companies.
BR: How has the FDA made it easier or more attractive for drug companies to develop products in orphan/rare diseases?
FDA: With orphan designation, a company gets tax credits for clinical trial costs (up to 50%). If your product is the first to be approved for a particular rare disease indication [i.e., authorized use], you get 7 years of marketing exclusivity.
rphan designation also gets you a waiver of the FDA’s user fee ($1.9M), which is a fee companies who submit a marketing application to FDA must typically pay.
BR: How are the approval requirements for orphan drugs different?
FDA: To be approved in the U.S., all drugs must demonstrate substantial evidence of efficacy and safety, which is usually done through the conduct of at least one adequate and well-controlled clinical trial. There is no requirement that all drugs go through Phase 1, Phase 2, and two Phase 3 trials. This is often the case for common diseases, but each development program is different, and there has been considerable flexibility shown for rare disease development programs. The FDA can exercise flexibility and scientific judgment. It is important to work closely with FDA to discuss the design of clinical development programs for rare diseases that are able to demonstrate substantial evidence of efficacy and safety.
FDA: Most (about two-thirds) orphan drugs are approved based on one adequate and well-controlled clinical trial and supportive information. What constitutes substantial evidence of effectiveness and safety will depend on what is known about the disease and population studied, the drug, and several other factors.
BR: Are there even less strict requirements for drugs aimed at ultra-orphan diseases?
FDA: There is no official term of “ultra-orphan” diseases. All are rare (also known as orphan) diseases. In the U.S., an orphan disease is defined by law as one that has a prevalence of less than 200,000 in the U.S. Most rare diseases are low prevalence (10,000-20,000 patients or fewer). Most approved products are for low prevalence diseases.
BR: Are requirements for orphan/rare drugs the same in other countries? (for instance, Europe and Japan) If not, what are the key differences?
FDA: This is outside of our authority. The regulatory requirements are not completely harmonized. Most of the time, FDA and other International Conference on Harmonisation (ICH) regulatory agencies, such as the European Medicines Agency (EMA), agree on approval decisions for orphan drug applications, and orphan designations. Many programs are multinational and we do collaborate quite a bit with authorities in other countries.
BR: From a regulatory perspective, are all orphan/rare diseases the same? If not, what are the different categories?
FDA: There are 7,000 rare diseases. They affect different age groups, have widely varying symptoms, exhibit different disease severities, etc. We talk about rare diseases like they are monolithic, but they are highly diverse. When thinking about orphan designation, understanding the disease is very important (e.g., is it one single disease or two diseases?) We even give orphan designation for subsets of common diseases.
FDA: With rare diseases, there is limited opportunity for study so you have to understand what is feasible, but other factors about the disease, the drug, and the expected effects of intervention are very important. The general principles of clinical research still apply.
FDA: Product candidates that come to the FDA for review are routed by disease or therapeutic area to the review divisions. For instance, a drug for skin diseases would generally be reviewed by the Division of Dermatology and Dental Products (DDDP).
BR: Are pemphigus and pemphigoid different from other orphan diseases from a regulatory perspective?
FDA: We searched our orphan designation database. We haven’t seen a lot of orphan designations for pemphigus. Ultimately, the same fundamental regulatory, scientific and clinical research principles would apply to drug development for pemphigus as for other diseases; however, the specific considerations for clinical development of a drug for pemphigus should be discussed with the review division.
BR: For ultra-orphan diseases like pemphigus and pemphigoid, what happens if there just are not enough patients to enroll in a trial? For instance, people may be too frail to participate in the trial, or they may not live close enough to a clinical trial site such as an academic medical center.
FDA: Most of these diseases are low prevalence. Most rare diseases are serious disorders, and many have patients who are very ill and medically vulnerable. This is where the concept of flexibility comes in. There is considerable diversity in approaches to developing drugs for rare diseases. For instance, in two-thirds of situations, only one adequate and well-controlled (A & WC) trial or another non-traditional study design is done. In contrast, for most common diseases, two A&WC trials are usually done. In unusual cases for some diseases, a case series is submitted. There is an example of a drug development program in which a clinical study of 8 people supported the approval of a drug. The important thing is to collaborate and talk to the FDA early and to arrive at a good trial design. Through this, we can often be quite successful.
BR: The FDA approves drugs for particular uses or “indications.” However, physicians can prescribe drugs for non-approved uses. For instance, Rituximab is approved for several uses (e.g., rheumatoid arthritis, certain types of lymphoma) but not for pemphigus, yet some doctors use it to treat pemphigus. How is this possible?
FDA: Drugs are prescribed by practitioners off label all the time. Medication choice is governed by the practice of medicine. The FDA does not regulate clinical practice. Based on what a physician knows about a patient, he or she does what is in the best interests of that patient.
FDA: Whether a drug is on-label or off-label does have implications for reimbursement.
BR: If Rituximab™ were studied in a pemphigus trial, would it have a faster path for being approved for use in pemphigus?
FDA: It’s a complicated question. You are re-purposing the drug. If you have a new drug with no prior use in humans, you have a long path with toxicology and other preclinical work that needs to be done. With a repurposed drug, you may already have that early work completed. You may then be able to jump in right at phase 2 and phase 3, but it depends on the circumstance. One should contact the relevant FDA review division to discuss trial design. If Rituximab were studied in pemphigus or pemphigoid, it may be eligible for orphan drug designation and all the incentives, including exclusivity.
BR: Given off-label usage is possible, what would be the utility of conducting a trial of an already approved drug in a new disease indication like pemphigus?
FDA: If you are deliberately measuring outcomes in a group of people (versus simply prescribing the drug to single patients), it becomes more of a research situation and you need to consider conducting this under an investigational new drug application, which is a type of authorization for doing investigational work.
BR: What can patient organizations do to support and accelerate the development of drugs?
FDA: You can do a lot. For rare diseases, one of the biggest problems is that patients are sparsely dispersed. It can be difficult to enroll trials. Describing natural history is very important, and patient organizations can help here. Also, many physicians may not be trained to treat patients with this disease. Patient groups can start registries (with type of disease, geographic location, etc.). Some organizations have initiated treatment centers – so if a treatment becomes available, they would have expertise and best practices located at one site.
BR: Is there a particular stage of the drug development and regulatory process where patient organizations can be most impactful?
FDA: All phases. Early on, trying to establish research registries, centers of excellence, and clinical endpoints is helpful. With slow trial enrollment, patient organizations can turn around the situation. Patient groups can help all the way through.
BR: Is there anything a patient advocacy group can do to assist the FDA’s review and approval process?
FDA: The FDA has a patient representative program. Through this program, patients can provide perspective at FDA advisory meetings. It is also important to partner with sponsors [e.g., drug manufacturers]. Sponsors may be willing to share information from trials, whereas the FDA cannot provide such data.
BR: Are there particular orphan drug policy efforts at play in Washington, DC that we should be aware of?
FDA: It is hard for us to comment on legislative activities.
BR: Are there particular orphan/rare disease organizations or groups we should collaborate with?
FDA: More experienced and larger groups are always willing to mentor smaller groups (e.g., cystic fibrosis group will talk to you and give you advice). NORD and the Genetic Alliance also do a lot of mentoring. The Genetic Alliance has boot camps. Get in touch with the Office of Rare Diseases Research at NIH. They can be very helpful. Rare Disease Day seminars, web casts, and events can also be helpful.