Personalized Medicine

Xenotransplantation: Ethics and Public Policy Need To Catch up to the Science

Claire Colby, MJLST Staffer

In early January, surgeons at the University of Maryland Medical Center made history by successfully transplanting a genetically altered pig heart to a human recipient, David Bennett.  The achievement represents a major milestone in transplantation. The demand for transplantable organs far outpaces the supply, and xenotransplantation–the implantation of non-human tissue into human recipients–could help bridge this gap. In the U.S. alone, more than 106,000 people are on the waiting list for transplants. Legal and ethical questions remain open about the appropriateness of implementing xenotransplants on a large scale. 

The FDA approved the January transplant through an emergency authorization compassionate use pathway because Bennett likely would have died without this intervention. Larger clinical trials will be needed to generate enough data to show that xenotransplants are safe and effective. The FDA will require these trials to show xenotransplantations are non-inferior to human organ transplants. IRB requirements bar interventions where risk outweighs benefits for patients, but accurately predicting and measuring risk is difficult. 

If xenotransplantation becomes standard clinical practice, animal rights proponents may balk at the idea of raising pigs for organs. Far before that point, pre-clinical trials will make heavy use of animal models. Institutional Animal Care and Use Committees (IACUCs) which oversee animal research in universities and medical entities apply a “much lower ethical standard” for animals than human research subjects. Bioethicists apply a “3R” framework for animal subjects research that stresses replacing animal models, reducing animal testing, and refining their use. Because of the inherent nature of xenotransplantation, applying this framework may be near impossible. Ongoing discussions are needed with relevant stakeholders.  

If both human and animal organs are approved for widespread transplant, but human organs prove superior, new allocation policies are needed to determine who gets what. Organ allocation policy is currently dictated by the Organ Procurement and Transplantation Network (OPTN). As it stands, organ transplantation shows inequality across racial groups and financial status. New allocation policies for organs must not reinforce or worsen these disparities. 

Like all medical interventions, patients must be able to provide informed consent for xenotransplantation. The recipient of the altered pig heart had previously been deemed ineligible for a human heart transplant because his heart failure was poorly managed. Reserving experimental interventions, like xenotransplantations, for the sickest patients raises serious ethical concerns. Are these desperate patients truly able to give meaningful consent? If xenotransplantation becomes a common practice, the traditional model of institutional review boards may need updating. Currently, individual institutions maintain their own IRBs. Xenotransplantation of altered animal organs may involve several sites: procurement of the organ, genetic editing, and transplantation may all take place in different locations. A central IRB for xenotransplantation could standardize and streamline this process. 

In all, xenotransplantation represents an exciting new frontier in transplant medicine. Responsibly implementing this innovation will require foresight and parallel innovation in ethics and public policy. 


You Wouldn’t 3D Print Tylenol, Would You?

By Mason Medeiros, MJLST Staffer

3D printing has the potential to change the medical field. As improvements are made to 3D printing systems and new uses are allocated, medical device manufacturers are using them to improve products and better provide for consumers. This is commonly seen through consumer use of 3D-printed prosthetic limbs and orthopedic implants. Many researchers are also using 3D printing technology to generate organs for transplant surgeries. By utilizing the technology, manufacturers can lower costs while making products tailored to the needs of the consumer. This concept can also be applied to the creation of drugs. By utilizing 3D printing, drug manufacturers and hospitals can generate medication that is tailored to the individual metabolic needs of the consumer, making the medicine safer and more effective. This potential, however, is limited by FDA regulations.

3D-printed drugs have the potential to make pill and tablet-based drugs safer and more effective for consumers. Currently, when a person picks up their prescription the drug comes in a set dose (for example, Tylenol tablets commonly come in doses of 325 or 500 mg per tablet). Because the pills come in these doses, it limits the amount that can be taken to multiples of these numbers. While this will create a safe and effective response in most people, what if your drug metabolism requires a different dose to create maximum effectiveness?

Drug metabolism is the process where drugs are chemically transformed into a substance that is easier to excrete from the body. This process primarily happens in the kidney and is influenced by various factors such as genetics, age, concurrent medications, and certain health conditions. The rate of drug metabolism can have a major impact on the safety and efficacy of drugs. If drugs are metabolized too slowly it can increase the risk of side effects, but if they are metabolized too quickly the drug will not be as effective. 3D printing the drugs can help minimize these problems by printing drugs with doses that match an individual’s metabolic needs, or by printing drugs in structures that affect the speed that the tablet dissolves. These individualized tablets could be printed at the pharmacy and provided straight to the consumer. However, doing so will force pharmacies and drug companies to deal with additional regulatory hurdles.

Pharmacies that 3D print drugs will be forced to comply with Current Good Manufacturing Procedures (CGMPs) as determined by the FDA. See 21 C.F.R. § 211 (2020). CGMPs are designed to ensure that drugs are manufactured safely to protect the health of consumers. Each pharmacy will need to ensure that the printers’ design conforms to the CGMPs, periodically test samples of the drugs for safety and efficacy, and conform to various other regulations. 21 C.F.R. § 211.65, 211.110 (2020). These additional safety precautions will place a larger strain on pharmacies and potentially harm the other services that they provide.

Additionally, the original drug developers will be financially burdened. When pharmacies 3D print the medication, they will become a new manufacturing location. Additionally, utilizing 3D printing technology will lead to a change in the manufacturing process. These changes will require the original drug developer to update their New Drug Application (NDA) that declared the product as safe and effective for use. Updating the NDA will be a costly process that will further be complicated by the vast number of new manufacturing locations that will be present. Because each pharmacy that decides to 3D print the medicine on-site will be a manufacturer, and because it is unlikely that all pharmacies will adopt 3D printing at the same time, drug developers will constantly need to update their NDA to ensure compliance with FDA regulations. Although these regulatory hurdles seem daunting, the FDA can take steps to mitigate the work needed by the pharmacies and manufacturers.

The FDA should implement a regulatory exception for pharmacies that 3D print drugs. The exemption should allow pharmacies to avoid some CGMPs for manufacturing and allow pharmacies to proceed without being registered as a manufacturer for each drug they are printing. One possibility is to categorize 3D-printed drugs as a type of compounded drug. This will allow pharmacies that 3D print drugs to act under section 503A of the Food Drug & Cosmetic Act. Under this section, the pharmacies would not need to comply with CGMPs or premarket approval requirements. The pharmacies, however, will need to comply with the section 503A requirements such as having the printing be performed by a licensed pharmacist in a state-licensed pharmacy or by a licensed physician, limiting the interstate distribution of the drugs to 5%, only printing from bulk drugs manufactured by FDA licensed establishments and only printing drugs “based on the receipt of a valid prescription for an individualized patient”. Although this solution limits the situations where 3D prints drugs can be made, it will allow the pharmacies to avoid the additional time and cost that would otherwise be required while helping ensure the safety of the drugs.

This solution would be beneficial for the pharmacies wishing to 3D print drugs, but it comes with some drawbacks. One of the main drawbacks is that there is no adverse event reporting requirement under section 503A. This will likely make it harder to hold pharmacies accountable for dangerous mistakes. Another issue is that pharmacies registered as an outsourcing facility under section 503B of the FD&C Act will not be able to avoid conforming to CGMPs unless they withdraw their registration. This issue, however, could be solved by an additional exemption from CGMPs for 3D-printed drugs. Even with these drawbacks, including 3D-printed drugs under the definition of compounded drugs proposes a relatively simple way to ease the burden on pharmacies that wish to utilize this new technology.

3D printing drugs has the opportunity to change the medical drug industry. The 3D-printed drugs can be specialized for the individual needs of the patient, making them safer and more effective for each person. For this to occur, however, the FDA needs to create an exemption for these pharmacies by including 3D-printed drugs under the definition of compounded drugs.


Industry Giants Praise FDA Draft Guidance on Companion Diagnostics

Na An, MJLST Article Editor

In July 2016, the US Food and Drug Administration (FDA) published a draft guidance document titled “Principles for Codevelopment of an In Vitro Companion Diagnostic Device with a Therapeutic Product.”  The new draft guidance aims to serve as a “practical guide” and assist sponsors of drugs and in vitro diagnostics (IVD) in developing these two products simultaneously.  So far, FDA has received six public comments on the draft guide which are mostly positive, with Illumina calling the document “worth the wait,” and Genentech claiming it “crucial for the advancement of personalized medicine.”

A companion diagnostic includes a medical device, in this case an in vitro device, which provides safety and efficacy information of a corresponding drug or biological product.  It is a critical component of precision medicine, the cornerstone of which is the ability to identify and measure biomarkers indicative of the patient’s response to a particular therapy.  Approximately, a quarter of new drugs approved over the past two years were a drug-IVD companion.  However, the codevelopment process is complicated by the fact that these two products may be developed on different schedules, subject to different regulatory requirements, and reviewed by different center at the FDA.  The long-awaited draft guidance was in the works for more than a decade and intended to help sponsors and the FDA reviewers navigate these challenges.

In this draft guidance, FDA reiterates its general policy that IVD devices should receive marketing approval contemporaneously with the authorization of the corresponding therapeutic product.  FDA states that “the availability of an IVD with ‘market-ready’ analytical performance characteristics . . . is highly recommended at the time of initiation of clinical trials intended to support approval of the therapeutic product.”  FDA also recommends: “Using an analytically validated test is important to protect clinical trial subjects, to be able to interpret trial results when a prototype test is used, and to help to define acceptable performance characteristics for the development of the candidate IVD companion diagnostic.”  The new draft guidance provides much more information about the technical and scientific aspects of the development process.  For example, the draft guidance details the use of IVD prototype tests for the purpose of testing the drug early in the development, considerations for planning and executing a therapeutic product clinical trial that also includes the investigation of an IVD companion diagnostic, the use of a prospective-retrospective study approach, the use of training and validation sample sets, and the use of a master file for the therapeutic product to provide data in support of the IVD companion diagnostic marketing application.

The draft guidance has received high marks from industry giants. Illumina said the draft “has been a long time coming, eagerly anticipated, but worth the wait.”  Yet, the gene sequencing giant also seeks more clarity from FDA on risk assessments and expectations for analytical validation prior to investigational IVD use in trials.  “There is an opportunity here for FDA to add clarity on this important decision making process. We suggest this discussion on significant risk versus nonsignificant risk determinations be expanded and put into an appendix with examples. This is a unique opportunity for FDA to help sponsors get this process right,” Illumina says.  On a similarly positive note, Genentech called the draft “crucial for the advancement of personalized medicine,” and supplementary to two previous guidance documents on next generation sequencing.  In addition, Genentech notes that the scope of this IVD and drug co-development draft guidance “is limited, and therefore it does not address the requirements for development of complementary diagnostics or the challenges of co-development using high-throughput technologies such as Next-Generation Sequencing (NGS) based test panels, which are an increasingly attractive tool for both developers and providers.”  AstraZeneca, on the other hand, seeks more clarity on guidance on complementary diagnostics and clarifying between “patient enrichment” and “patient selection” and the resulting considerations on determination of significant risk uses of investigational devices.

We eagerly wait for FDA’s view of these comments and impacts of the guidance on the codevelopment of a drug-IVD companion.