Orphan Drugs

Slide 1

Now orphan drugs. Orphan drugs are a category or a mechanism to encourage and facilitate the development of drugs for rare diseases or conditions.

Slide 3

Now, a rare disease or a condition is a disease or condition that affects less than 200,000 persons in the United States or can affect more than 200,000 persons but for which there is no reasonable expectation that the cost of developing and making available in the US a drug for such a disease or condition will be recovered from sales in the United States.

When one applies for orphan drug on status, one applies for what is called orphan drug designation. First, you need to go to the agency and submit an application and request a designation that your product is indeed a rare disease or a product for a rare disease or condition.

This program is administered by the Office of Orphaned Products Development, which in the Office of the Commissioner. This group is involved in the identification of orphaned products, the facilitation of the development, and it also administers the orphan drug, a program.

However, the scientific review and medical review of these products are conducted in the scientific and medical review centers of the FDA. So, the Center for Drugs Evaluation Research and the Center for Biologics Evaluation and Research will conduct these reviews.

However, the centers do work closely with the Office of Orphan Products. As this office is in the Commissioner’s Office, there is a lot of oversight of this program by the Commissioner.

Now, these studies, the clinical studies for these products are going to be very small patient population wise just because there are not a lot of people with the disease or condition that you’re studying. Even though the number of patients in these studies, and I’ve seen approval of some of these drugs where you have 30 patients, even though you do have a small number of patients, the studies that you conduct still need to be adequate and well-controlled. You can imagine from a statistical perspective how difficult that can be. It’s wonderful that this program is in place for orphan drugs and there’s a lot of success stories and a lot of sponsors and applicants try to take this route whenever possible. But it is challenging. It is challenging because the patient numbers are so small, and powering a study to demonstrate efficacy can be quite challenging.

Slide 4

Here are the incentives for development of drugs for rare diseases and conditions. One of the incentives is seven years of marketing exclusivity once the product is approved. During this seven year period, FDA will not approve the same drug for the same disease or same condition. As the product that’s received orphan drug, a designation. The seven years of marketing exclusivity begins on the date of approval and it is only for the indication for which the drug has been approved. Another application could be approved for the same drug in a different indication. Tax credits are another incentive for orphan drug development and these are tax credits for clinical research to generate data required for marketing approval of that indication. The FDA grants formal protocol assistance. The agency will assist the sponsor in coming to agreement and providing input on clinical protocols, which is more guidance than one usually receives from the agency.

The agency also has research grants available to give to sponsors who are developing these products and these grants run from $200,000 per year for a phase one study to $350,000 per year for phase two and phase three studies. These research grants are … they go up to three years in length. The agency also provides written recommendations on the pre-clinical and clinical investigations. Now, according to the agency, this assistance that the agency gives sponsors usually results in decreased development time.

Slide 5

Now if someone has an approved orphan drug and another company has developed a drug that is clinically superior to that orphan drug this superior drug can break orphan drug exclusivity. So it can break the seven year marketing exclusivity period that this orphan drug has. So you can have the same drug for the same indication as a previously designated product, but if that product is clinically superior then the seven year marketing exclusivity will be broken and that is to ensure that patients will benefit from this clinically superior drug.

Now, clinical superiority can be demonstrated in one of three ways. One is greater effectiveness as assessed by an effect on a clinically meaningful endpoint in adequate and well-controlled studies. So one would need to do a head-to-head study of the currently marketed product against this investigational drug to determine clinical superiority that way.

Clinical superiority can also be a demonstration of greater safety in a substantial portion of the target population. And then once again that’s a head-to-head study looking at safety parameters.

And the last is a demonstration that the drug makes a major contribution to patient care. An example of this would be if someone has a product that is given by IV infusion once a week and another company comes along and develops the same product that can be taken as a pill. That’s obviously a major contribution to patient care.

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Speeding Access to Therapies

Slide 1

FDA has taken steps towards making investigational drugs more widely available to severely ill patients as well as towards speeding the review and approval of NDAs and BLAs for these products. This lecture will cover access to investigational drugs outside of a clinical trial and speeding the review and approval of NDAs and BLAs.

Slide 3

FDA allows access to investigational drugs for patients with serious or immediately life-threatening diseases or conditions who lack other therapeutic options. It is not always possible for all patients who want access to investigational drugs to enroll in clinical trials. Patients may not meet eligibility criteria or may be geographically isolated from a study site. In these situations, FDA makes promising, but still investigational products available outside of a clinical trial to patients with serious and life-threatening illnesses. This investigational therapy is offered in a way that does not pose an unreasonable risk to the patient and retains valuable information about the effect of the drug. This is through treatment use or emergency use of the investigational drug.

Speeding the development and availability of drugs that treat serious diseases are in everyone’s interest, especially when the drugs are the first available treatment or have advantages over existing treatments. The FDA has developed approaches to making such drugs available as rapidly as possible. There are many mechanisms under which this can be done, but the mechanisms that we will discuss in this lecture include sub-part E, priority review, accelerated approval, and fast track. Please note that these mechanisms are not mutually exclusive.

Slide 4

First, let’s look at treatment use. During the clinical investigation of a drug, it may be appropriate to use the drug in the treatment of patients or a single patient not in the clinical trials through a treatment protocol or treatment IND. This allows promising new drugs to be made available to desperately ill patients as early in the drug development process as possible. Additional data on the drug safety and effectiveness is also obtained. A drug is ordinarily made available for treatment use during phase three or after all clinical trials have been completed. However, in some circumstances, a drug may be made available for treatment use during phase two.

Although treatment may be focused on an individual patient, a study protocol may be written to ensure that the treatment is administered appropriately and that patients are monitored for toxicity. It is important to note that a manufacturer of the investigational drug must first agree to provide the product. FDA cannot mandate that the requested products be supplied. Informed consent must be provided to the patient, an IRB must be in place, and IND safety reports must be submitted.

Slide 5

The second manner which we’re going to look at to expand the use of these therapies beyond an investigational trial, or a clinical trial that’s already in place, is through emergency use.

Emergency use is defined as a use of an investigational drug, in a life threatening situation, where no standard acceptable treatment is available, and in which there is not sufficient time to obtain IRB approval.

The emergency use provision in the SDA Regulations is an exemption from prior review, and approval by the IRB.

This exemption allows for one emergency use of an investigational drug without perspective IRB review.

Even for an emergency use, the investigator is required to obtain informed consent. However, informed consent can be weighed, as we discussed in the lecture, only informed consent to review. As we discussed in the lecture on informed consent. You may want to go back and review that lecture, because the exemptions for when informed consent need not be obtained, are discussed in that lecture, and I’m not going to repeat them here.

Emergency use of an investigational drug requires an IND. If the intended subject does not meet the criteria of an existing study protocol, or if an approved study protocol does not exist, the usual procedure is to contact the manufacturer and determine if the drug can be made available for emergency use under the company’s IND.

The need for an investigational drug may arise in an emergency situation, that does not allow time for a submission of an IND. In such a case, FDA, may authorize shipment of the drug in advance of an IND submission.

Slide 6

Now we’re going to move into some mechanisms that FDA has in place to expedite the review of NDAs and BLAs and speed approval of products to the market. Notice that these mechanisms do not speed the review of INDs. They are only for the marketing application phase of development.

And first we’re going to look at Sub-Part E regulation, and Sub-Part E is somewhat of a slang phrase that we use to describe this process, which is codified in Sub-Part E of Part 312 of Title 21 of the Code of Federal Regulations.

The agency’s procedures in Sub-Part E of the IND Regulations expedite the development, evaluation and marketing of therapies to treat individuals with life-threatening and severely debilitating illnesses. This part was put in place in 1988 in response to the AIDS crisis, and on this slide, I’ve given you the definitions of life-threatening and severely debilitating diseases or conditions, and these definitions apply to other expedited and expanded access programs.

This regulation reflects that the agency must make a medical risk benefit judgment in deciding whether to approve a drug product. While this decision making is taken for granted today, in 1988, when this regulation was first codified, this was novel thinking.

As part of this risk benefit analysis, the agency takes into consideration the severity of the disease, and the absence of satisfactory alternative therapy. Procedures reflect the recognition that physicians and patients are generally willing to accept greater risks or side effects from products that treat life-threatening and severely debilitating illnesses, than they would accept from products that threat less-serious diseases.

Under Sub-Part E, drug development is considered a continuum, from early pre-clinical and clinical studies, through submission of a marketing application. The regulations emphasize the critical nature of close and early communication between the agency and the sponsor, outlines procedures, such as pre IND and end of Phase One meetings as methods to improve the efficiency of pre-clinical and clinical development and focus on efforts by the agency and the sponsor to reach early agreement on the design of the major clinical efficacy studies that will be needed to support approval.

The thinking codified in Sub-Part E provided a foundation for laws, regulations and procedures outlining in the Prescription Drug User Fee Act and the FDA Modernization Acts that were put in place in the mid-1990s.

Slide 7

FDA’s accelerated approval procedures are available for drugs that have been studied to treat serious or life threatening illnesses, and that provide meaningful therapeutic benefit to patients over existing treatments. For example, the ability to treat patients unresponsive to, or intolerant of, available therapy. Under these procedures, FDA may approve drugs based on surrogate endpoints that reasonably predict that a drug provides clinical benefit. This clinical benefit is then confirmed through additional clinical studies that are completed after approval.

These studies must be adequate and well controlled, and are usually underway when approval is granted. In fact, if they aren’t underway, at least a protocol has to be put in place, and the agency has to provide input that that protocol is adequate. The approach under accelerated approval, also provides for removal of the drug from the market if further studies do not confirm the clinical benefit of the therapy.

Slide 8

Priority review facilitates the development and expedites the review of drugs that are intended to treat serious or life-threatening conditions and that demonstrate the potential to address unmet medical needs. Review classifications for NDAs and BLAs have been established to prioritize the review of these submissions. A priority designation is intended for drugs that have the potential for providing a significant improvement compared to marketed products in the treatment, diagnosis, or prevention of a disease, or a product that eliminates or substantially reduces a treatment limiting drug reaction, enhance patient willingness or ability to take the drug, or establish safety and effectiveness in a new subpopulation such as children.

When a BLA or NDA is filed with the agency, a review time period is assigned for the marketing application. A standard application for drugs which offer only minor improvement over existing therapies is given a 10 month review timeframe. A marketing application that is assigned priority review receive a six month timeframe. At the end of that timeframe, the FDA must issue an action letter, which is a letter that either contains deficiencies that need to be addressed prior to the drug being approved, or it is an approval letter. So if one is able to receive a priority review designation when the company submits the NDA or BLA, then one has the ability to gain an additional four months on the market with the product. If you’ve got a blockbuster product, that’s a lot of revenue that you’re generating during that four month period.

Slide 9

The fast track program is designed to facilitate the development and expedite the review of drugs that are intended to treat serious or life-threatening conditions and that demonstrate the potential to address unmet medical needs. An unmet medical need is defined as a medical need that is not addressed adequately by an existing therapy. Advantages include more frequent meetings and written correspondence with the agency and rolling review. A rolling review is when a company submits a BLA that is not complete. If a company under other circumstances submits a BLA that is not complete, meaning that sections in the BLA are missing, the sponsor or the applicant will receive a refuse-to-file letter, so the agency will not file that BLA or NDA. Now, there is a filing fee associated with NDA and BLA filings. It’s close to a million dollars today in 2018. If FDA refuses to file your application, they keep a piece of that, a chunk of that filing fee, so not only do you have to resubmit your application, but you also lose a lot of money.

Now, under fast track, you can submit sections of your NDA or BLA and not have FDA refuse to file the application. For example, when we do drug development, frequently the CMC section is the first to be completed for our marketing application, and usually the clinical section is the last to be completed, because one is waiting for the results and analysis of that Phase 3 study. Under fast track, when your CMC section is completed, you can submit that to the agency and have them begin your CMC review and get questions and deficiencies back to you prior to submitting your clinical section, prior to submitting your preclinical section. It does offer a great advantage timewise in that the agency is looking at sections of the application as they are complete, and you don’t have to wait for the entire application to be complete prior to filing.

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Chemistry, Manufacturing & Controls (CMC)

Chemistry, Manufacturing & Controls (CMC)

Slide 3

Now the amount of information for the C&C section that you need to submit is dependent upon the stage of the clinical investigation, the duration of the investigation, and the dosage form. And the data we have to submit to the agency is the data to allow the reviewers to allow the agency to ensure that the product has the correct identity, quality, purity, and potency for that stage of development, and the amount of this information will vary. For example, a stability data needs to be submitted, which demonstrates that the product that you are giving to patients is within specification for the duration of the clinical trial. If you’re doing a single ascending dose study for your phase one study, then your trial time may be very short, it may be a week to get all your subjects dosed, so you would only need a very short period of time for your stability study.

However, if you’re in phase three and your study is one or two years of duration, then you need to make sure that you’ve got data demonstrating that the product will remain within specification for one to two years. So this is an example of how the amount of information, and the type of information, and the length of the study, and that data that one submits to support a clinical investigation in the duration of that investigation will be a variable. Now it’s well understood that the manufacturing process, and the product itself, will undergo optimization during the clinical phases, and thus the manufacturing process will change. And as that manufacturing process changes then additional information needs to be submitted to the agency to document those changes.

Prior to phase one the focus of the agency review is on the safety to subjects. And all data that needs to be submitted for the C&C prior to phase three needs to have a focus on safety. Any data that does not affect safety can be submitted during phase three. Now the agency does have the ability to put a clinical study on hold. What this means is that the agency will not allow the study to proceed if there is a safety concern, or if there is a lack of sufficient data for the agency to make an evaluation that the product is safe. And for a chemistry manufacturing and controls, reasons for concern may include a product that is made with unknown or impure components.

One can have a product possessing chemical structures of known or highly likely toxicity. A product can have an impurity profile, which indicates a potential health hazard, or insufficiently designed, or insufficiently defined impurity profile to assess the health hazard, or one may have a poorly characterized master or working cell bank. But what is important is that one identify, monitor, and assess signals of potential human risk in prior to the clinical study, for example, that may arise due to the manufacturing process.

Slide 4

Now, components are ingredients intended for use in the manufacture of a drug product, including those that may not appear in such drug product. For example, for our biotechnology products that are derived via fermentation, then ingredients that we add to enable cell growth, to enable cell reproduction, to enable the production of our protein are considered components. Even though these components may not appear in the final drug product, it is very important to know the source of these components. For example, we frequently use human serum albumin as a stabilizer in the final product of four proteins. One must trace the source of that HSA, and ensure that there are no adventitious agents, et cetera, that may affect the safety of the subjects in the clinical trial.

We also use fetal bovine serum in the fermentation of our mammalian cells, and one needs to assess the risk of BSC for this product. In the CMC section, we need to provide the agency with a general method of preparation of the product, to include the reagents, solvents, and components that we used, so that they can make a determination that these are safe. It in general is better to use compendial, versus non-compendial components. Compendial components being components that have monograph in the USP, the European Pharmacopoeia, or some sort of national formulary designation.

Slide 5

One must ensure that the product that one gives to subjects in a clinical trial has known chemical structures. Also, one must make sure that the structures are not likely to develop into toxicities in the subjects. That’s a lot more important with the small molecules than it is for the large.

What we need to do for the CMC section, in this regard, is we do a structural analyses looking at not only the amino acid sequence, but also at the peptides of the product, and we determine identity down to that level. If there’s a glycosylated chain, a glycosylated structure on the molecule, we need to understand the oligosaccharide pattern of that change, and the site of the glycosylation.

Physical chemical properties are also important. We measure molecular weight or molecular size through SE-HPLC, SDS-PAGE, mass spec. We look at isoform patterns to gain an understanding of what that range will be. We use electrophoretic patterns to look at identity of the pattern, to look at homogeneity and purity of the product itself, and we use various liquid chromatographic patterns, such as SE-HPLC, RP-HPLC, in order to gain an understanding of the physical chemical properties of the product.

Slide 6

I get asked a lot what does a typical protein characterization look like. On the previous slide, we looked at molecular characterization in general. To what level does a molecule have to be characterized? There’s a lot one can do.

This slide shows what a typical protein characterization would look like. One verifies amino acid sequence by using peptide mapping. Identity impurity can be confirmed using isoelectric focusing. Molecular weight can be determined using mass spec. SDS-PAGE is a good way to confirm the molecular mass and amino acid sequence, et cetera.

One thing I do want to mention about biologics is that the term efficacy is one that is not presented in the PHS Act, which is one of the laws for which most of the biologics in the United States are approved under. We use the term potency, and for biologic potency means a biological activity. Potency is usually determined by using a binding assay, such as an ELISA.

Slide 7

Now impurities can also result in safety issues that need to be monitored during clinical development. There are two types of impurities. There’s process related impurities and product related impurities. Process related impurities are impurities that are derived from the manufacturing process. They may be derived from self substrates, such as host cell proteins that the cells naturally produce, or host cell DNA that’s naturally produced by the cells. They can be derived from cell culture, such as inducers that we use to initiate a protein production, or they can be derived from downstream processing, such as leachables from the columns that we use for purification.

Product related impurities are molecular variants of a desired product. And these molecular variants do not have properties comparable to those of the desired product, with respect to activity, efficacy, and safety. So these molecular variants are truncated forms, deaminated forms, and they may be oxidized forms, and they can lead to the development of immunogenicity due to the formation of aggregates or neoepitopes.

Now impurities may be of known structure. They may be partially characterized, or they may be unidentified, but one needs to ensure that they are characterized to the extent possible. If possible, biological activity should be evaluated for the impurity, and there are many methods available to do that, such as HPLC, SDS Page, OMS Spec, immuno acids hybridization techniques, et cetera.

Slide 8

Now, a certificate of analysis for a drug product to be used in a clinical trial will contain usually the following tests. The certificate of analysis separates these tests into the areas of: quality, potency, purity, identity, and safety.

The typical quality tests are appearance, such as color and visual particulates and pH. For the potency assay, typically an ELISA is used. Purity may be determined using SEC, HPLC, SDS-PAGE, reverse phase HPLCs. There are many ways to determine identity such as peptide mapping and terminal sequencing, et cetera. And safety testing consists of sterility testing, testing for endotoxins, and also looking for host cell DNA.

Slide 9

Now, the master cell bank, and the working cell bank from which cells are taken and used in the production of biotech products can lead to a safety issue during clinical development. And in order to ensure that an IND is not put on hold, due to a CMC issues, one of the issues that the agency does look at, is a master or working cell bank to ensure that it’s been adequately characterized. That one has an understanding of the identity, purity, and suitability of the cell substrate and that that has been confirmed.

I’m giving you two definitions here, and this is all taken from ICH Q5B and Q5D. A master cell bank is an aliquot of a single pool of cells, which generally has been prepared from the selected cell clone. It’s dispensed into multiple containers and stored under defined conditions. And from this master cell bank, one derives a working cell bank. And that working cell bank is used on an every day basis.

Now, a company may or may not have the cell banks. It is completely appropriate to have solely a master cell work and not have a working cell bank. But one needs to confirm the identity, the purity, and the suitability of the cell substrate. For purity, one needs to ensure that the cell banks are free from adventitious agents and contaminates. If one has a mammalian cell bank, one is looking at bioburden, microplasma levels, and the level of viruses. For microbial cells, one does a visual examination to see if there’s any contaminating colonies. Looks for the presence of bacteriophage, gram-staining is done to ensure the identity, and to ensure also that the purity.

Identity in this sense means that the bank cell is what it is represented to be. And there’s a number of tests that one can use for that. For microbial cells, one grows the cells on selective media, ensuring that they are pure, and ensuring that they are what they’re supposed to be. And one can also do partial genotyping.

For mammalian cells, one looks for markers that may be unique to the mammalian cells when they do a DNA analysis and a morphological analysis. A genetic analysis is also done, looking to ensure that the genetic construct has been retained and that the DNA sequence of the construct is also there. So that’s the type of level that one needs to characterize the master and working cell banks, prior to entering clinical development.

Now, that’s the last slide that I have for the CMC section, and what’s required for the CMC section. Just to recap, chemistry manufacturing and controls can result in a safety concern to the agency that would result in a clinical holder that could result in a clinical hold being put on a clinical trial. So one needs to make sure that the manufacturing process is not introducing any additional safety concerns. Because when we get into clinical development, the safety of the subjects is the number one priority and the number one concern.

And these reasons for concern may include unknown or impure components. It may include a product possessing chemical structures of known or highly likely toxicity. It could include an impurity profile that may lead to a potential health hazard or it could be an impurity profile that hasn’t been sufficiently defined or sufficiently characterized. Or one could have a poorly characterized master or working cell bank. And all of these issues may result in the agency not being able to determine if the product is safe for use in clinical studies.

So now we’re going to-

Slide 10

The lecture today covered a lot of material. We covered preclinical from an in vitro and an in vivo perspective and we looked at setting the maximum [CMC 00:00:07] safe starting dose for our first in human study. Next week we’re going to look at [Faith One 00:00:29] studies. We’re going to look at clinical trials in general and get more into a clinical development. Please don’t hesitate to contact me either by e-mail or by phone if you have any questions. Thank you

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Pediatric Drug Development

Slide 1

For this lecture we’re g oing to be looking at pediatric drug development. A drug development in pediatrics can be quite challenging due to the unique concerns within this population.

Slide 2

First, let’s define the pediatric population, and this is defined from birth to 16 years. The reason that pediatric drug development can be challenging is that there are fundamental differences between growing and developing children and adults. These include differences to drug response, differences in the toxicity profile, rates of drug development, and also the trials that we do to assess safety and efficacy in children are different. Or the way we design them are different than in adults.

Children are also considered a vulnerable population, and according to ethical codes of conduct we need to protect children. Clinical trials create risk for any subject within the study, however children may be exposed to increased risk just because of their age and developmental status. However, not conducting clinical trials creates risk for all children, because then physicians don’t know how to dose the products.

So, as a result of these challenges, product labeling frequently failed to provide directions for safe and effective use in pediatric patients. This led to a situation where clinicians were either reluctant to provide drugs to pediatric patients because they didn’t know how to dose them correctly, or if they did provide drugs to patients, they were dosed inappropriately because dosing was arbitrarily chosen and selected.

Slide 3

Therefore, need existed for regulations to avoid adverse drug reactions in children, but also to ensure that the doses provided to children were efficacious and that children weren’t being untreated. So as a result, physicians prescribe drugs, usually off-label, for the pediatric population. A result of this was exposing children to drugs that were untested in the pediatric population because they were solely tested at end results. From the perspective of pharmaceutical companies, they’re usually not interested in gaining labeling in children just because it’s a small target population, so there isn’t any great revenue stream there. There’s also concerns about adverse events that could potentially cause issues where the drug, as a whole …

Slide 4

So this was realized within the medical community and within FDA. So FDA made some changes in order to encourage companies to put a pediatric labeling on their products. In 1979, a section was added which required labeling providing direction for pediatric use. And this labeling notified physicians that below a certain age that the safety and efficacy of the drug had not been established in this group of patients. And then in 1994, a regulation required manufacturers of marketed drugs to survey their existing data and determine whether the data was sufficient to support pediatric use. If so, the manufacturers were required to submit a supplement to their license containing that data to change their label. If not, then the manufacturers had to change the label to read safety and effectiveness in pediatric populations has not been established. However, both of these requirements were viewed by industry and the agency as being voluntary. There was not any enforcement mechanism. And because of this viewpoint, they were insufficient to bring about change.

Slide 5

In 1997 the FDA Modernization Act was signed into law. This provided an incentive for manufacturers to change their labeling to include the pediatric population. This provided market exclusivity for an additional six months to manufacturers who voluntarily conducted and submitted to FDA pediatric studies of their drugs. However, this still left significant gaps in obtaining the data for these studies and in changing the labeling.

This is due to the fact that products that did not have specific existing patent or exclusivity protection, this marketing exclusivity couldn’t be prolonged because there wasn’t any protection to prolong. Some drugs were also not included, such as antibiotics and also biological products licensed under the Public Health Service Act. Some manufacturers simply chose not to perform these studies because they had no interest and the exclusivity wasn’t worth it to them. Also, this exclusivity provision could only be used once with respect to an active ingredient.

If additional studies were required, then the exclusivity provision did not kick in so there was no economic incentive. This provision of the Modernization Act expired on January 2002.

Slide 6

In 1999, the Pediatric Rule became effective, and these regulations can be found in 314 for NDAs, and 601 in BLAs. This rule required regulations, or established regulations that required pediatric studies. And these are for products that are likely to be commonly used in children, or that represent a meaningful therapeutic benefit over existing treatments. Marketing applications for new active ingredients, new indications, new dosage forms, new dosage regimens, and new routes of administration have to contain a pediatric assessment, unless a waiver or deferral has been obtained. And this pediatric assessment needs to be conducted through clinical trials.

Manufacturers also get regulatory benefits from the Pediatric Rule in that they receive early consultation with the agency during the investigational study. And it’s also a benefit to the agency, because it provides FDA with the ability to require the development in a pediatric formulation, which is also a challenge when it comes to giving drugs to children, especially oral drugs in that they don’t readily swallow pills. So we need to develop usually liquid formulation for this population.

Slide 7

The Pediatric Rule can also be required for already marketed drugs, and these are drugs that are used in a substantial number of pediatric patients, and where inadequate labeling can pose significant risks, and a substantial number of patients, [inaudible 00:00:28] 50,000 pediatric patients in the United States, with a disease or condition for which the drug is indicated. And these are also in patients that would provide … where the therapy would provide a meaningful benefit over existing treatments, and this means a significant improvement in the treatment, diagnosis, or prevention of disease as compared to a marketed product. The Pediatric Rule, however, doesn’t apply to orphan drugs, and it doesn’t apply to generic drugs.

Slide 8

In 2002, the Best Pharmaceuticals for Children Act was signed into law, and this reauthorized the Exclusivity Incentive Program enacted through the FDA Modernization Act. And this, once again, established a voluntary testing legislative framework. FDA must determine that the pediatric testing provides health benefits to that population in order for the agency to request that this testing be done. If FDA does determine that there’s health benefits, then FDA makes a written request to the manufacturer to conduct the study. The manufacturer then agrees to conduct the study within the appropriate timeframe. And then then manufacturer conducts tests and submits the reports to the FDA. So, there’s a process that needs to be followed here in order for these studies to be conducted.

Slide 9

A best also authorized NIH to fund studies and established a private fund. And it also gave FDA some enforcement ability. If the agency felt that the product needed to be reformulated, for the pediatric population and if labeling changes are needed to be made. And the manufacturer didn’t want to make these changes or to do any reformulation studies. Then the FDA has the ability to take this request to the advisory committee. If the advisor committee agrees with the agency and the manufacturer still refuses, then enforcement action can be taken by the FDA.

Now the downside within this law is that it doesn’t extend to biological products. The awarding of study contracts doesn’t extend to biological products or certain antibiotics. And public funding is dependent on yearly congressional appropriations. Now this was reauthorized in 2007 and this law sunsets in 2012.

Slide 10

In 2002, there was an important court case where the district court for this District of Columbia held that FDA had exceeded its statutory authority when issuing the Pediatric Rule. And the court suspended its implementation and enjoined its enforcement. And once again, we find physicians with those pediatric patients having limited treatment options.

Slide 11

A physician once again had this issue with off-label use and during this court case the plaintiffs argued that FDA does not have the authority to require manufacturers to conduct studies of drugs for uses that they do not intend to seek or devise formulation for these uses.

Slide 12

The court concluded that the legal basis did not exist for the Pediatric Rule and FDA had exceeded their statutory authority. As a result of this court case FDA enacted PREA in 2003 and they codified elements of the suspended Pediatric Rule and attempted to fill the gaps left by the Pediatric Rule suspension. This was retroactive back to 1999 when the Pediatric Rule was first enacted.

However, as we design these studies, we need to take in consideration the specific needs of the population and address any ethical issues in trial design considerations that are unique to pediatric studies.

Slide 13

So let’s get into drug development, and exactly when to conduct pediatric studies, and how to conduct pediatric studies, now that we’ve got all these histories.

So we conduct pediatric studies for life threatening conditions when no adequate treatment is available. And before we conduct these studies, we need to make sure that we have initial safety data. So we first have to study the drug in adults. And these pediatric studies usually begin in phase one or in phase two. So they begin early in drug development, but once you’ve already gone into a first in human study and then adult population. Now for less serious diseases, you may conduct these studies later in drug development.

In some cases, you also may not begin these studies until after approval, due to scientific and ethical issues. And there are certain cases when you may not conduct pediatric studies, where a product has not shown any benefit over an adequately labeled product, or the therapeutic need is low, or where the risk of exposing pediatric patients to a new product may not justify conducting these studies. Or you may conduct them once a safety profile has been well-established in adults, so you may even wait until after your product is well into phase three or already on the market before you conduct these studies.

When one is scoping out their drug development program, one needs to have discussions with the FDA very early on regarding their pediatric indication and regarding the studies. If you’re developing a product for life threatening or severely debilitating illness, then these development plans should be discussed with the agency during the pre-IND meeting.

For other products, these plans should be submitted to the agency at the end of a phase two meeting, prior to going into your pivotal studies in phase three.

Slide 14

Waivers can be granted, FDA can grant either full or partial waivers. If the product does not represent a meaningful, therapeutic benefit over existing treatments and is not likely to be used in a substantial number of pediatric patients, then a full waiver is granted. If the studies are impossible or highly impractical, because there’s a low number of patients or because these patients are geographically dispersed, again, a full waiver can be granted, or if there’s strong evidence that products would be ineffective or unsafe in the pediatric age group. Also, for some diseases we don’t see the diseases in the pediatric population, so of course then you would also not need to conduct clinical trials for patients in the pediatric population.

Slide 15

A partial waiver can also be granted and this is when studies aren’t conducted in specific age groups. So you may conduct studies, for example, in patients 16 years old or older and exclude all patients below the age of 16. Partial waivers are granted using the same sort of thinking as a full waiver and the conditions are when there doesn’t seem to be a meaningful therapeutic benefit over existing treatment, the product is not likely to be used in a substantial number of patients or the studies are impossible or highly impractical, once again, due to the number of patients or because of the disbursement of the patients geographically throughout the US. There’s strong evidence that the product isn’t effective or unsafe in the pediatric age group. But also, if a manufacturer has attempted to develop a pediatric formulation and those attempts have failed. For example, some oral drugs may not dissolve well enough to have a liquid formulation. Therefore, you can receive a partial waiver based on that.

Slide 16

Clinical trials in the pediatric population can also be deferred until after the BLA or NDA has been filed. And, there’s various factors feeding in to this decision. One factor is that agency wants to make sure that the drug approval isn’t held up because you’re doing studies in the pediatric population. So, you don’t want any waiting here or any drugs being held up for patients in need because there isn’t a pediatric label put in place. There’s also the need for the drug, which is a factor in the decision making process. The availability of sufficient safety data to initiate pediatric trials. You may need to wait until after your product is on the market and you’ve got sufficient data in adults before you initiate these studies. There’s also the nature and extent of data to support a pediatric labeling, the existence of substantiated differences in enrolling patients, differences between adults and pediatrics, and also the evidence of technical problems in developing pediatric formulations. It may take longer for you to develop your formulation than you had anticipated.

Slide 17

Now, FDA also has enforcement action that they can take if pediatric studies weren’t conducted. But the drug may be considered to be mis-branded or not approvable. If the drug is mis-branded, the agency can issue an injunction. They can prosecute individuals or they can seize the product and prevent it from being distributed. However, these enforcement actions are only taken in rare cases because the agency doesn’t want to deprive patients of a useful medical product. Any issues that come up in this area can be presented and discussed with the pediatric advisory committee.

Slide 18

Now, the Pediatric Advisory Committee advises and makes recommendations to the Commissioner regarding pediatric research, regarding ethics, and the design and analysis of pediatric therapeutics, labeling disputes, labeling changes, adverse events, et cetera, et cetera.

Slide 19

Other considerations in the design of clinical studies for pediatrics is that your IRB must have pediatric expertise and also that placebo controlled study may be difficult to conduct if their use doesn’t place the pediatric population at increased risk. This is also a challenge to the pediatric … to the conduct of pediatric studies. It may be difficult to conduct a pediatric study using an already marketed product as a comparator because most of the products are labeled for adults and not the pediatric population. So this requires the use of a placebo study or the use of a placebo which can also cause ethical issues to arise when one uses a placebo in a vulnerable population.

Slide 20

The preclinical studies that we do prior to doing a pediatric trial is different from the preclinical studies that we do to support a trial in the adult population because of the development stage of this pediatric population. So, we need to select animals that exhibit the same developmental characteristics as the pediatric population that we’re going to … that we’re going to be studying and using in our clinical study. So, we use young animals to support the preclinical safety evaluation for these studies. And, the focus of the preclinical safety evaluation is on the potential effects of the drug on growth and development. And we only do these studies when we haven’t conducted studies already that can provide support for these clinical studies, or to further investigate issues that have arisen in previous preclinical, or perhaps, our clinical studies.

And these studies may be conducted separately in juvenile animals or one may conduct toxicology studies to support an adult indication but amend the design of that study to include juvenile animals. And when we design these animal studies, we need to ensure that the age of the pediatric population of the clinical study is going to be adequately represented in the developmental stage of the animals. And-

Slide 21

There’s other considerations before we do these studies or in the design of these clinical studies in general. What one consideration is, of course, the intended or likely use of the drug in children. If it’s not going to be used in children, then, of course, we don’t do these studies.

Another is the timing of the dose in relation to phases of growth and development. Animals develop a lot faster than humans, and it’s very important that that dose be given right at the right time or you’re going to miss that window of opportunity.

One also needs to consider the potential differences in pharmacological and toxicological profiles between the mature and immature systems. And also, of course, we always need to consider differences between animals as they are relative to the clinical population and to humans in general.

When we think about the age of the animals to use in these studies, we need to consider, too, that the younger the pediatric population is that we’re going to study in our clinical study, the more dynamic and faster their growth rate is. So we need to make sure that that animal population is adequately represented.

Slide 22

This is a chart looking at the age of various animal models and the development that occurs. And this is used to demonstrate just the age difference, the developmental differences, between these animal models and humans. For example, if you’re doing a clinical study in pediatric population that is entering puberty or within puberty, which is about 11 to 12 years for us humans, then you’re going to be doing your preclinical study in monkeys that are between two and a half and three years old, and dogs that are between six and eight months, or, yeah, eight months of age, and rats that are two to three months old, and in a mouse that’s 35 to 45 days. And then this chart also shows you if you’re doing lung studies what age you’re looking at in rats and mice to be comparable to the human. And also if you’re doing studies looking at for example the growth hormone and looking at growth, which is frequently measured by ossification of the long bones, in this case the femur, then you also have a comparable time to the human and to the animal models.

Slide 23

A lot of ethical issues come up in the design of clinical studies for this population. And, these ethical issues need to be addressed and there’s various ways that we address them. In the composition of the IRB, we ensure that there are members of the IRB who are knowledgeable in the conduct of the pediatric studies, in the development of pediatric patients, in psychological issues, and then of course, in all the ethical issues.

When we recruit patients, we need to be sure that the recruitment process is free from inappropriate inducements. And, these inducements can be not only to the study participant, but also to the parent or legal guardian of that study participant. As with all drugs, or as with all clinical studies, any monetary compensation is reviewed by the IRB and it has to be approved by the IRB. Informed consent can be challenging because the pediatric subject is frequently unable to provide informed consent. So, the consent is obtained from the individual’s parent or a legal guardian. And, this person needs to assume responsibility for the participation in clinical studies.

Participants need to be fully informed to the greatest extent possible about the study in a language that they can understand and in terms that they can also understand. If the participant is of an age where they are intellectually mature, then they should personably sign and date the written informed consent. In all cases, as with all clinical studies, participants should be made aware of the right to decline to participate, or their ability to withdraw from the study at any particular time.

Attention should also be paid to signs of undue distress in these patients because of their age, they may be very young, and they may not be able to clearly articulate their distress as adults do.

Slide 24

Distress of course needs to be minimized in any clinical study. But we do special things to minimize distress in this pediatric population. We should that personnel who are conducting the study have an understanding, and are skilled in dealing with the pediatric population, and their age-appropriate needs.

We do these studies in a comfortable physical setting. And this physical setting includes play equipment, furniture, activities, and food that is appropriate to the age of the subjects.

In order to decrease distress, we also conduct these studies in a familiar environment where participants normally receive their care. So we try not to make a lot of changes. And we take various approaches to minimize discomfort, such as usually using topical anesthesia to place IV catheters, we use the dwelling catheters rather than doing repeated venipunctures for blood sampling. And we try to lessen the number of samples that we take by taking a protocol specific blood samples when routine clinical samples are taken.

Slide 25

So, in summary, developing drugs for pediatrics can be challenging just because pediatric patients are different than adult patients due to the developmental stage that they’re in and the rapid growth that they’re undergoing, and also psychologically. FDA regulations require that pediatric information be included in the drug labeling, and so we need to conduct studies in the pediatric population.

Slide 26

Here’s some references, if you’d like to have, for the reading on the topic.

Slide 27

And if you have any questions please contact me at my email address. Thank you.

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