Enzyme Replacement Therapies: Classification and Pharmacovigilance

Purpose and Scope

Enzyme replacement therapy (ERT) is a form of biological treatment in which an administered enzyme is used to replace, supplement or restore an enzyme activity that is deficient or absent. The concept is most closely associated with inherited metabolic disorders, particularly lysosomal storage disorders, although therapeutic enzymes are also used in other clinical settings. The pharmacovigilance of these products is shaped by the relationship between enzyme structure, cellular or tissue delivery, residual endogenous activity, treatment duration, immune recognition and the clinical consequences of both excessive and insufficient biological activity.

The scientific basis of ERT makes it distinct from a conventional small-molecule medicine. The administered protein must reach the relevant biological compartment and retain sufficient functional activity to modify the disease process. Consequently, safety assessment may need to consider not only the pharmacological target but also uptake, distribution, enzyme activity, immune responses and the underlying disease. In lifelong or long-duration treatment, these considerations can evolve over time as cumulative exposure, treatment interruptions, product changes and disease progression alter the clinical context.

This article establishes the type-level framework for enzyme replacement therapies within the QPPV.com biological-product series. It first explains the biological rationale for enzyme replacement and the principal ways these products can be classified. It then considers production and product characteristics, pharmacology, immunogenicity and clinical development before connecting these features with individual case assessment, signal management, aggregate evaluation, risk management and inspection. Specific products and individual disease areas are reserved for subsequent articles where a separate evidence base is warranted.

The general EU pharmacovigilance requirements apply to ERT as they do to other medicinal products. Additional considerations arise from their status as biological medicinal products, including the need to understand product-specific characteristics, maintain appropriate traceability and integrate relevant immunogenicity and product-quality information into safety assessment. EMA's GVP guidance on biological medicinal products provides the product-specific framework, while the general GVP modules establish the broader pharmacovigilance system. [1]

Biological Basis of Enzyme Replacement

Many inherited metabolic disorders result from pathogenic variants that reduce or abolish the activity of an enzyme required for a defined biochemical pathway. Depending on the disease, reduced activity can cause accumulation of a substrate, deficiency of a downstream product, abnormal storage within cells, or a combination of these effects. The clinical phenotype reflects the tissues affected, the degree of residual enzyme activity, the timing of disease progression and other biological modifiers.

ERT introduces a functional enzyme from an external source. The therapeutic objective is not necessarily to reproduce every aspect of endogenous enzyme production. Instead, the administered protein must provide enough functional activity in the relevant compartment to alter the pathological process. This distinction explains why delivery and intracellular trafficking are central to the pharmacology of many enzyme-replacement products.

For lysosomal storage disorders, the therapeutic enzyme may need to enter cells and reach lysosomes. Uptake can depend on receptor-mediated pathways and on molecular features that permit cellular recognition and trafficking. Once delivered to the appropriate compartment, the enzyme catalyses the relevant reaction and can reduce accumulated substrate or improve the affected metabolic pathway. The extent of clinical benefit depends on disease biology and on whether the administered enzyme reaches the tissues in which pathology is clinically important.

The pharmacovigilance implications follow directly from this mechanism. An apparent lack of efficacy is not necessarily evidence of product failure, and an adverse event is not necessarily explained by the catalytic activity of the enzyme. Disease progression, treatment timing, baseline phenotype, dose, exposure, immune responses, administration reactions and other clinical factors can all contribute to the observed outcome. A robust safety assessment therefore requires the product mechanism and the disease context to be considered together.

Classification of Enzyme Replacement Therapies

ERT can be classified in several complementary ways. The most useful classification for pharmacovigilance begins with the biological function being restored and then considers the disease compartment, route and molecular characteristics of the enzyme. This avoids treating all therapeutic enzymes as though they had a common safety profile.

These dimensions should be treated as complementary rather than mutually exclusive. Two products used for related diseases may differ substantially in structure, uptake mechanism or immunogenicity. Conversely, products with different indications may share pharmacovigilance considerations because they have similar administration characteristics or immune-response mechanisms.

Therapeutic Enzymes and Enzyme Replacement

The term therapeutic enzyme is broader than ERT. Some enzymes are administered to replace a missing physiological function, while others are intended to modify a pathological substrate or biological process without correcting an inherited enzyme deficiency. ERT is therefore best understood as one important subgroup within the wider category of therapeutic enzymes.

This distinction matters when interpreting class-level safety information. An infusion reaction associated with one recombinant enzyme does not establish a class effect across all therapeutic enzymes, just as immunogenicity observed with one molecular construct does not demonstrate that every enzyme replacement product has the same immune risk. The relevant assessment must remain anchored to the individual product's structure, manufacturing process, clinical use and evidence base.

Within ERT, the strongest commonality is the therapeutic objective of supplying functional catalytic activity. The pharmacovigilance profile remains product-specific because the clinical consequences of enzyme replacement depend on the disease, the molecular construct, cellular uptake, treatment regimen and patient population.

Product Structure and Biological Activity

Enzymes are proteins whose biological activity depends on their three-dimensional structure and catalytic site. Recombinant production must therefore preserve the characteristics required for functional activity, stability and appropriate distribution. Relevant product attributes may include amino-acid sequence, folding, glycosylation, charge characteristics, aggregation, purity, potency and other quality attributes appropriate to the particular enzyme.

For lysosomal enzymes, molecular features involved in cellular uptake may be therapeutically important as well as structurally descriptive. Alteration of such features can affect the amount of enzyme reaching the intended intracellular compartment even when the protein retains catalytic activity in an analytical assay. Pharmacovigilance assessment should therefore distinguish a general measurement of enzyme activity from evidence that the administered product produces the expected biological effect in patients.

Product structure also provides one part of the basis for understanding immunogenicity. A recombinant protein may be recognised as foreign by the immune system, particularly where endogenous enzyme activity is absent or markedly reduced. The resulting immune response can range from detectable anti-drug antibodies without an apparent clinical consequence to responses that alter pharmacokinetics, reduce functional activity or contribute to hypersensitivity. The existence of antibodies alone does not establish a clinically meaningful safety or efficacy effect.

Development and Manufacturing Considerations

The development of an enzyme replacement product begins with establishing that the administered enzyme can provide a clinically meaningful biological function. This requires characterisation of the molecule and demonstration of suitable quality attributes, biological activity and consistency of manufacture. Clinical development then has to account for the natural history of the underlying disease, which can be particularly important when the disorder is rare, progressive and heterogeneous.

The manufacturing process is closely connected with the quality profile of a recombinant enzyme. Expression, purification, formulation and storage can affect characteristics such as aggregation, structural integrity, glycosylation, impurities and potency. These attributes are controlled through the pharmaceutical quality system and are not themselves pharmacovigilance endpoints. Their pharmacovigilance relevance arises when clinical safety information or a safety hypothesis requires consideration of product-quality information, or when a quality change has potential clinical implications.

For an established product, changes to manufacturing may be necessary to increase capacity, improve process control, introduce a new facility or modify a production step. Such changes are evaluated through the applicable quality and regulatory framework. Comparability is intended to establish whether the pre- and post-change products remain comparable with respect to relevant quality, safety and efficacy considerations; it should not be assumed that every manufacturing change creates a new safety signal. ICH Q5E provides the general scientific framework for comparability of biotechnology-derived products subject to manufacturing changes. [2]

Pharmacokinetics, Distribution and Pharmacodynamics

The pharmacology of an enzyme replacement product differs from that of a small molecule because the administered protein may be subject to proteolytic degradation, receptor-mediated uptake and tissue-specific distribution. Plasma concentration is therefore only one component of the exposure picture. Depending on the product and disease, the clinically relevant effect may depend on uptake into cells and delivery to a specific intracellular compartment.

Pharmacodynamic assessment may include biochemical markers of substrate reduction, restoration of enzyme activity, changes in disease-associated biomarkers or other measures appropriate to the individual product. These measures can help distinguish biological activity from clinical outcomes, but none should automatically be treated as a surrogate for patient benefit without supporting evidence.

The distinction is particularly relevant to pharmacovigilance cases involving lack of efficacy. A patient may experience continued disease manifestations despite evidence of enzyme activity, while another may have reduced biological response because of antibodies, altered exposure or interruption of treatment. Disease progression can also mimic treatment failure. Case assessment should therefore capture the clinical indication, disease severity, treatment history, dose and schedule, relevant laboratory or biomarker findings and any evidence concerning immune responses when these data are available.

Immunogenicity

Immunogenicity is a central consideration for many enzyme replacement products. The administered protein can induce binding or neutralising antibodies, and immune responses can also manifest clinically through hypersensitivity or infusion-related reactions. The probability and consequences of an immune response depend on product-related factors, treatment-related factors and patient-related factors rather than on the simple fact that the medicine is a recombinant protein.

The clinical interpretation of anti-drug antibodies requires particular care. Binding antibodies may have no detectable effect on clinical outcomes, whereas antibodies with neutralising activity may reduce enzyme function or interfere with the intended therapeutic mechanism. Antibodies may also influence the disposition of the protein or correlate with infusion-related reactions. The presence, titre, timing and persistence of antibodies therefore need to be interpreted together with pharmacokinetic, pharmacodynamic, efficacy and safety information.

In patients with little or no endogenous enzyme activity, the immune response may be clinically important because the administered enzyme represents a substantial new antigenic exposure. Conversely, immune tolerance can vary considerably between diseases and patients. The pharmacovigilance system should therefore preserve sufficient clinical context to distinguish a laboratory immunogenicity finding from a clinically consequential immune-mediated event.

EMA's guideline on immunogenicity assessment of biotechnology-derived therapeutic proteins recommends a risk-based approach integrating product quality, the treatment regimen and patient characteristics. [3] For pharmacovigilance, this means that immunogenicity information should be available for signal assessment when relevant, while avoiding an assumption that every detected antibody response is pathological.

Administration-Related Reactions and Hypersensitivity

Many enzyme replacement therapies are administered by infusion, making administration-related reactions an important part of their safety surveillance. Symptoms may include flushing, fever, chills, rash, respiratory symptoms, changes in blood pressure or other manifestations occurring during or shortly after administration. The mechanism may involve an immune response, cytokine release or another infusion-related process, and the clinical phenotype alone may not establish the underlying mechanism.

Repeated exposure creates an additional temporal dimension. A patient who tolerates early infusions can subsequently develop reactions, while a patient with an established reaction pattern may tolerate later administrations after a change in infusion rate or other clinically appropriate management. Pharmacovigilance assessment should therefore capture the timing of onset in relation to infusion, the sequence of previous administrations, treatment interruption or re-exposure, concomitant medication and the clinical management of the event.

Severe hypersensitivity reactions require particular attention because they can affect future treatment decisions. A pharmacovigilance system should preserve the distinction between an adverse reaction reported during infusion and a confirmed immunological mechanism unless the evidence supports that conclusion.

Disease-Related Confounding

Enzyme replacement therapies are often used in rare progressive disorders with multisystem manifestations. The same symptom may therefore represent disease progression, a complication of the underlying disorder, an intercurrent condition or an adverse reaction to treatment. This creates a recurring challenge for individual case assessment and aggregate signal evaluation.

The problem is not solved by assigning a symptom to the medicine whenever it occurs after administration. Temporal association is relevant but must be interpreted with disease history, baseline status, expected disease course, alternative explanations, treatment exposure and dechallenge or rechallenge information where available and clinically meaningful.

Disease-related confounding is especially important for reports of lack of efficacy. A patient may deteriorate despite appropriate therapy because irreversible disease damage has already occurred or because the therapeutic mechanism does not address all manifestations of the disorder. Conversely, a genuine reduction in treatment effect may be obscured by an assumption that all deterioration is attributable to natural history. Pharmacovigilance therefore benefits from structured capture of disease status and treatment response rather than reliance on a single reported outcome.

Product Identification and Traceability

Accurate product identification is essential when multiple biological enzyme products are used in the same therapeutic area. The case record should capture the medicinal product, strength or presentation as applicable, manufacturer or marketing authorisation information where relevant, batch or lot information when available, route of administration and dates of exposure. These data support case assessment and can become particularly important when a signal raises a question concerning a specific product, manufacturing change or batch.

Traceability is also important when patients receive more than one biological product over time. A report of a hypersensitivity reaction or reduced response after a switch cannot be interpreted reliably if the administered product is not identifiable. The objective is not to assume that switching caused the event, but to preserve enough information to permit an evidence-based assessment.

Pharmacovigilance Across the Product Lifecycle

The pharmacovigilance system for an enzyme replacement product should evolve as evidence accumulates. During early development, safety information is generated in relatively small and selected populations. After authorisation, exposure expands to patients with broader disease characteristics, different levels of disease severity and varying patterns of concomitant treatment. Long-term treatment can also reveal events that are difficult to characterise in shorter clinical studies.

Individual case reports remain an important source of evidence, but their interpretation is strengthened when the report is placed within the product's known safety profile and the characteristics of the treated population. For ERT, useful information can include the indication and disease phenotype, treatment duration, dose and infusion schedule, previous exposure, relevant laboratory findings, immune-response information, concomitant therapies and clinical outcome.

Signal management should connect individual observations with aggregate evidence. A cluster of infusion reactions, for example, may prompt examination of timing, infusion conditions, dose, batch information, concomitant treatment and patient characteristics. A report of reduced therapeutic response may prompt evaluation of adherence, disease progression, neutralising antibodies, treatment interruptions and product exposure. Neither pattern establishes a signal by itself; the subsequent assessment determines whether the evidence supports a new or changed safety concern.

Signal Detection and Evaluation

Safety signals for enzyme replacement therapies can arise from spontaneous reports, clinical studies, literature, registries, post-authorisation studies, scientific information and other relevant sources. The relative value of each source depends on the question being investigated. Rare severe infusion reactions may be visible through individual case reports, whereas gradual changes in treatment response may require longitudinal clinical or registry data.

Signal evaluation should distinguish an observation from an interpretation. A report that a patient developed a reaction during an infusion is an observation. A hypothesis that the reaction represents an immune-mediated response to the enzyme is an interpretation requiring supporting evidence. Similarly, the detection of anti-drug antibodies is an observation; concluding that those antibodies caused loss of efficacy requires evidence linking antibody characteristics with pharmacokinetic, pharmacodynamic or clinical outcomes.

The assessment should consider biological plausibility, temporal relationship, alternative explanations, consistency across cases, dose or exposure relationships where informative, relevant laboratory or immunogenicity data, dechallenge or rechallenge information where available, and evidence from other data sources. The strength of the conclusion should remain proportionate to the evidence.

Aggregate Reporting and Benefit–Risk Evaluation

Aggregate safety evaluation places individual reports within the broader evidence base. Periodic reports and other aggregate analyses should consider whether the observed safety profile remains consistent with the established reference safety information and whether new evidence changes the understanding of identified or potential risks.

For enzyme replacement products, aggregate assessment may need to consider cumulative treatment exposure, repeated administration, immunogenicity, administration-related reactions, disease-specific outcomes and long-term follow-up. The interpretation of event frequency can be challenging when the treated population is small and the underlying disease is rare. Numerical changes should therefore be interpreted in the context of exposure, reporting behaviour, ascertainment and the characteristics of the population under surveillance.

Benefit–risk evaluation also requires attention to the consequences of the underlying disease. A serious adverse reaction must be assessed against the therapeutic benefits that may otherwise be difficult to achieve in a progressive or life-limiting disorder. This does not reduce the importance of safety; it ensures that regulatory and clinical decisions consider the full evidence concerning benefits, risks and available alternatives.

Risk Management

Risk management measures should address risks supported by the evidence and should be proportionate to their nature and clinical significance. Depending on the product and its identified or potential risks, measures may include routine pharmacovigilance, product information, educational material, monitoring recommendations, additional studies or other regulatory measures.

For ERT, risk-management planning may need to address administration-related reactions, hypersensitivity, clinically meaningful immunogenicity or other product-specific risks. The appropriate measure depends on the evidence and on the feasibility of preventing or detecting the risk. A precaution should not be described as a mandatory requirement unless it is established as such in the applicable regulatory framework.

Risk-management activities also need measurable objectives. If an additional activity is intended to characterise a risk, the relevant study or surveillance system should be capable of generating evidence that answers the defined question. Pharmacovigilance governance should then track whether the evidence changes the risk assessment or requires further action.

Manufacturing Changes and Comparability

Manufacturing changes can occur throughout the life of a recombinant enzyme product. Because the biological activity of an enzyme depends on molecular and product characteristics, a change to the manufacturing process may require detailed quality and comparability assessment. The pharmaceutical quality system and regulatory framework determine the formal requirements for evaluating the change.

Pharmacovigilance has a complementary role. When a manufacturing change is associated with a safety observation, the timing of the change, affected product version, batch information and clinical evidence may become relevant to the investigation. Conversely, a quality change does not automatically constitute a pharmacovigilance signal. The safety conclusion must be based on the totality of the evidence.

The same principle applies when investigating apparent differences between product versions. Product identification, batch traceability, clinical exposure and relevant laboratory or immune-response information should be connected sufficiently to permit comparison. Where the evidence does not support a causal relationship, the uncertainty should be retained rather than replaced by an unsupported conclusion.

Special Situations

Several situations require additional care in ERT pharmacovigilance because they alter the interpretation of exposure or clinical outcomes.

Treatment interruption and re-exposure

An interruption followed by re-initiation can change the clinical context of an infusion reaction or other event. The case should preserve the timing of the interruption, previous tolerance, re-exposure and event onset. A temporal association after re-exposure may strengthen a hypothesis in some circumstances, but it does not by itself establish mechanism or causality.

Switching between biological products

Patients may move between products because of clinical, supply, reimbursement or other considerations. When this occurs, product-specific exposure history becomes essential. A safety event after switching should be assessed against the complete exposure history rather than attributed automatically to the new product.

Paediatric treatment and lifelong exposure

Many inherited metabolic disorders are diagnosed and treated during childhood. Developmental stage, body size, disease severity and duration of exposure can influence the clinical context. Long-term follow-up is particularly relevant where treatment continues for many years and where delayed consequences cannot be adequately assessed in short studies.

Pregnancy and lactation

Pregnancy exposure to an enzyme replacement product should be evaluated according to the available clinical, pharmacological and non-clinical evidence. Because pregnancy may alter disease management and pharmacokinetics, reports should capture exposure timing and relevant maternal and pregnancy outcomes. The existence of a pregnancy exposure does not itself establish a safety concern for the fetus or infant.

Concomitant treatment

Patients receiving ERT may also receive substrate-reducing therapies, immunomodulatory treatment, supportive medicines or treatments for complications of the underlying disease. Concomitant treatment can affect both the risk of adverse events and the interpretation of treatment response, making accurate medication history important for case assessment.

Roles, Interfaces and Evidence

Effective pharmacovigilance for enzyme replacement products depends on defined interfaces between safety, regulatory, medical, clinical development, quality and manufacturing functions. Pharmacovigilance remains responsible for the evaluation and management of safety information within the pharmacovigilance system, while quality functions investigate manufacturing and product-quality matters under the pharmaceutical quality system. The two systems must exchange relevant information when a safety question could reasonably involve product quality or a quality observation could have safety implications.

Medical and clinical functions provide important disease-specific and mechanistic context. Regulatory functions connect safety conclusions with applicable authorisation requirements and interactions with competent authorities. Where additional studies or registries contribute important safety evidence, the governance framework should ensure that the questions, methods, data ownership and resulting conclusions are documented.

The evidence supporting an important safety conclusion should be traceable. Depending on the issue, relevant records may include individual case reports, source information, product and batch details, laboratory or immunogenicity results, signal evaluations, aggregate analyses, study reports, quality investigations, regulatory correspondence and risk-management documentation. The required evidence is question-dependent; not every record needs to be retained in every assessment, but the reasoning leading to an important conclusion should be reconstructable.

Potential Failure Modes

Potential failures in ERT pharmacovigilance arise when the biological and clinical context is lost during routine processing. One example is treating every infusion reaction as though it had an established immune mechanism. Another is treating the detection of anti-drug antibodies as synonymous with clinically important immunogenicity. Both approaches can produce conclusions that exceed the available evidence.

A different failure occurs when lack of efficacy is attributed to the product without considering disease progression, treatment interruption, dose, exposure, neutralising antibodies or other explanations. The opposite error is also possible: assuming that deterioration is entirely disease-related and failing to investigate evidence suggesting reduced biological response.

Traceability failures can make otherwise important questions difficult to answer. If the administered product, batch or exposure dates are missing, it may be impossible to determine whether cases involve the same product or production period. Similarly, incomplete treatment history can obscure the relationship between repeated exposure and an adverse event.

These are potential failure modes, not claims that they represent documented inspection findings. Their value in quality management is to identify where a pharmacovigilance process could lose information needed for effective assessment.

Inspection Perspective

An inspection of pharmacovigilance for an enzyme replacement product could examine whether the system is capable of identifying, evaluating and governing safety issues in the context of the product's biological characteristics. The focus should be on objective evidence rather than on whether an organisation can recite the relevant scientific concepts.

An inspector could examine whether individual case processing captures sufficient product and exposure information, whether important immunogenicity findings are appropriately interpreted, whether signals are evaluated against disease-related alternative explanations, and whether relevant quality information is available when a safety question warrants it. The inspector could also examine whether decisions are documented and whether escalation pathways are defined.

For long-term therapies, inspection evidence may include the way cumulative exposure, treatment interruptions, switching and delayed events are incorporated into aggregate surveillance. Where registries or additional studies are used, the inspector could examine whether the resulting evidence is integrated into the pharmacovigilance system and whether conclusions are consistent with the defined study questions.

An effective system should therefore demonstrate a chain of evidence from the incoming observation through assessment, decision-making, action and follow-up. The precise records will depend on the issue, but the underlying principle is reconstructability.

Practical Implementation

A practical ERT pharmacovigilance process should begin by defining the product-specific safety questions that matter for the molecule and its indication. The safety specification should then inform the information that needs to be captured from individual reports, the data sources used for signal detection and the evidence required for aggregate assessment.

For products associated with infusion or hypersensitivity reactions, case-processing controls should preserve administration timing, reaction onset, severity, management and relevant re-exposure history. Where immunogenicity is clinically relevant, the system should allow antibody findings to be linked with clinical outcomes and other relevant evidence rather than storing them as isolated laboratory observations.

For products used in progressive rare diseases, the system should preserve enough disease context to distinguish treatment-related events from manifestations of the underlying disorder. This does not require every case to contain an exhaustive natural-history assessment. It requires proportionate collection of information that can materially affect causality, seriousness, expectedness, signal evaluation or benefit–risk interpretation.

Where product quality or manufacturing information becomes relevant, predefined interfaces should allow pharmacovigilance and quality teams to exchange the necessary information while maintaining their respective responsibilities. Batch and product traceability should be treated as an operational capability that supports investigation, not as evidence that a batch is unsafe.

Actionable Checklist

Relationship With the Wider Pharmacovigilance Framework

ERT illustrates a broader principle of biological-product pharmacovigilance: product characteristics determine which evidence is most informative, but they do not replace the general pharmacovigilance process. Individual case reports, signal management, aggregate reporting, risk management and benefit–risk evaluation remain interconnected components of the system.

The enzyme-replacement context adds scientific dimensions that must be carried through those processes. A safety observation may need to be interpreted against enzyme activity, cellular delivery, immunogenicity and disease progression. Product identification and traceability may become important when several biological products are used in the same population. Manufacturing information may become relevant when a safety question coincides with a product change. These connections explain why a product-specific pharmacovigilance framework is useful without creating a separate pharmacovigilance system for biological medicines.

The same framework also provides the foundation for subsequent QPPV.com articles on individual enzyme replacement products and specific therapeutic areas. Those articles can then concentrate on product-specific evidence rather than repeating the general principles established here.

Key Takeaways

Enzyme replacement therapies are biological medicines in which an administered enzyme provides functional catalytic activity to compensate for or modify a deficient biological process. Their pharmacovigilance requires an understanding of the relationship between molecular structure, biological activity, tissue or cellular delivery, immune recognition, exposure and clinical outcome.

The principal safety questions are product-specific. Infusion reactions, hypersensitivity, immunogenicity, altered treatment response and disease-related confounding can be important, but the presence or absence of any particular risk must be established from evidence for the individual product and population.

Effective surveillance therefore depends on preserving product identity, exposure history and clinically meaningful disease context; integrating immunogenicity information where relevant; connecting pharmacovigilance with quality and manufacturing functions when warranted; and evaluating observations through the established signal-management, aggregate-reporting, risk-management and benefit–risk framework.

References

1. European Medicines Agency. Good pharmacovigilance practices (GVP): Product- or Population-Specific Considerations II: Biological medicinal products. EMA.
2. International Council for Harmonisation. ICH Q5E: Comparability of Biotechnological/Biological Products Subject to Changes in Their Manufacturing Process.
3. European Medicines Agency. Guideline on immunogenicity assessment of biotechnology-derived therapeutic proteins. EMA/CHMP/BMWP/14327/2006 Rev. 1.
4. European Medicines Agency. Guideline on the clinical investigation of medicinal products for the treatment of Gaucher disease. EMA/CHMP/GTWP/20146/2007.
5. European Medicines Agency. Guideline on clinical investigation of medicinal products for the treatment of Fabry disease. EMA/CHMP/GTWP/165453/2005.
6. European Medicines Agency. Good pharmacovigilance practices (GVP), Module V: Risk management systems.
7. European Medicines Agency. Good pharmacovigilance practices (GVP), Module IX: Signal management.
8. European Medicines Agency. Good pharmacovigilance practices (GVP), Module VI: Collection, management and submission of reports of suspected adverse reactions to medicinal products.

Regulatory Note

This article describes the pharmacovigilance implications of enzyme replacement therapies within the EU framework. The general pharmacovigilance obligations applicable to medicinal products remain applicable to these products; biological medicinal products also require consideration of product-specific characteristics addressed in EMA's biological-medicinal-product guidance. Scientific and operational explanations in this article should not be interpreted as additional legal requirements unless the cited legislation, regulatory guidance or product-specific regulatory documentation establishes such an obligation. Requirements can change through amendments to EU legislation, revisions of GVP and other guidance, and product-specific regulatory decisions; current source documents should therefore be consulted when applying the framework to a particular product or case.