Background and current legislation

Due to some tragedies concerning human medical intervention studies in the past, the research involving patients and healthy volunteers is governed by strict regulation and legislation worldwide [1–3]. The purpose is to protect the safety of the participants and ensure credible results. See Table 1 [4].

Table 1 Regulation and Legislation worldwide
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Nowadays, the Declaration of Helsinki [5] and the Declaration of Geneva [6] represent the most important ethics policies of the World Medical Association (WMA) and are worldwide enforced. They are supported by practical guidelines focused on adequate Human Subject Protection (HSP) [5], Good Clinical Practice (GCP) [7], Good Manufacturing Practice (GMP) [8, 9], and Good Laboratory Practice (GLP) [4, 8]. See Table 2.

Table 2 Current practical guidelines
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Despite the attempt to harmonize legislation and guidelines, there are still significant differences between EU-member States’ legislation governing clinical research. One of the reasons is that some Member States feel the need to cover a broader scope than the EU Directive related to clinical research, resulting in country-specific legislation. There are also differences between the European Union and other continents, such as the U.S.A.

For clinical research with both registered and non-registered medicinal products (IMPs), and non-investigational medicinal products (non-IMPs), definitions and legislation are well described [10, 11]. See Table 3 and Fig. 1.

Table 3 Investigational products in clinical research
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Fig. 1
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Overview of investigational products

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In contrast to the manifest guidelines for IMP and non-IMP studies, the guidelines about products that are the subject of investigation, but not regarded as a medicine, non-Medicinal Investigational Products (non-MIPs) are undefined.

These are substances used in human intervention studies to examine the physiological and toxicological effects of these compounds as opposed to investigating its pharmaceutical action. These are usually regarded as challenging agents and shared among the non-Investigational Medicinal Products (See Tables 3 and 4), with less stringent regulations as compared to Investigational Medicinal Products [8]. See Table 4.

Table 4 Legislation for non-investigational medicinal products
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Unspecific guidelines, regulations and laws for the quality of these non-Medicinal substances represent a potential health risk to the individuals participating in trials and are causing lack of clarity to the investigators, the pharmacists, and the members of competent authorities. If the quality of the product cannot be vouched for, this can lead to unsafe research methods, even influencing the results and conclusions of a clinical trial. It is therefore difficult for the investigators to perform toxicological studies with such challenging agents.

We propose that, in order to guarantee the safety of the study subjects and the quality of the research, the investigators, who use non-Medicinal Investigational Products, will be encouraged to perform a thorough analysis and quality check of these products, including information on the raw product, the production proces of the final product, pre-clinal toxicity data, and a well-founded, product specific risk-benefit analysis. This information should be clearly documented and reviewed by the responsible competent authorities. Since these substances are not medicinal products, we are introducing an adapted Investigational Medicinal Product Dossier, simply a Product Dossier (PD), to supply Ethics Committees and Competent Authorities with adequate and sufficient information about the investigational product in a standardised way.

We will discuss the requirements for such a PD and will illustrate this with examples from the CARBON-study. Furthermore, we will share the hurdles that we have taken and lessons we have learnt to provide a helping hand when starting studies with non-Medicinal Investigational Products (non-IMPs).

Carbon-study

Human intervention with carbon nanoparticles

Particulate air pollution is increasingly recognised as an important causative factor in pulmonary diseases [12, 13]. To investigate the effect of carbon nanoparticles as a component of air pollution on bronchoalveolar inflammation, we aimed to develop a safe and accurate human in vivo research model. To that end, we developed a suspension of pure carbon nanoparticles, having a comparable size and structure as soot for bronchial segmental administration. The content of ink cartridges of laser printers appeared to fulfil these criteria. It is obvious that this product is not intended to be used in humans, therefore, we collected information on the raw product (characteristics and toxicity data), and thoroughly analysed the final product, in order to make a reliable risk-benefit analysis on the safety of the final product [14]. The main goals of the CARBON-study, in which we performed a bronchial segmental challenge with carbon nanoparticles in healthy volunteers, were:

  1. 1.

    To evaluate the safety of the study participants according to predefined criteria. Standardized endpoints were: increase in circulating leukocytes, adverse events, and complaints such as chest pain, dyspnea and cough. See also Table 5.

    Table 5 Proposed Safety Endpoints for Bronchial Provocation Studies in Humans
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  2. 2.

    To investigate the effect of carbon nanoparticles on pulmonary and systemic inflammation and coagulation. Primary endpoint was increase in local and circulating leukocytes

This study was approved by the institutional ethics committee and has been registered by the Dutch Trial Register with number 2976 at http://www.trialregister.nl/trialreg/admin/rctsearch.asp?Term=2976.

Analysis of the raw material

A major problem with non-Medicinal substances, such as carbon nanoparticles, is that the raw material is not produced according to GMP criteria and that thorough information about the quality of the product is often not available. Furthermore, there is no information available about formation of hazardous side products, because the origin of starting materials and the way of synthesis of the raw product are not well documented or govern by trade secrets. Additional analysis of the raw product is therefore necessary and a risk-based approach is required to decide which tests are useful to gather sufficient data on the quality of the product and the suitability for its use in a clinical study. Because of the unique character of each product, we need professionals with specific knowledge of the product, and professionals with knowledge of the expected physiological action in humans to perform this thorough analysis. The next important step after finding the right product, is to perform toxicological studies in vitro and in animals. See Tables 6, 7 and the CARBON- Product Dossier (Additional file 1).

Table 6 Specifications for Printex-U- suspension in saline
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Table 7 CARBON-study; analysis of raw material
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Fig. 2
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Transmission Electron Microscopic (TEM) image of Printex-U. A cluster of particles with a primary particle size of < 50 nm is shown

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Final product: manufacturing, quality control and stability (See Table 8)

In line with regulation for medicinal products, it is important to pre-define the criteria the final product should meet. Furthermore, the manufacturing proces from raw material to final product and their associated risks should be described in detail. If possible, it is preferable to perform the proces controls.

Table 8 CARBON-study; analysis of final product
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After manufacturing, a quality control has to be performed on the final product to assess whether the product meets the pre-defined criteria. For the specifications of a product, pharmaceutical guidelines may be helpful. Next to this, as very specific analytical methods and equipment may be necessary, it is mandatory to have an agreement with the laboratory about the standard operating procedures and the quality system of the laboratory.

Stability testing is required in the development of Investigational Medicinal Products and it is usually ongoing during the development. For non-Medicinal products it is also necessary to perform stability testing in the final container to exclude formation of hazardous side products during storage and decrease in activity of the active compound.

Product specific risk benefit analysis

In the risk-benefit-analysis the current knowledge about effects in human, animal and in vitro studies are summarised, followed by discussing (possible) mechanism of action, selectivity of the mechanism to target tissue, quality of the product, the concentration analysis, the quantitative regular daily exposure, the study design, and analysis and manageability of potential effects [15]. The investigators should also indicate how they intend to reduce the risks of the potential effects to a level that is acceptable in relation to the scientific importance of the study [16]. Dosage and route of administration are vital issues in clinical research and part of the risk-benefit analysis. A clear description is neccesary to assess safety for study participants. See Table 9 [17–19].

Table 9 CARBON-study; design, dosage, administration
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Product dossier

All the collected information and test results on the product should be systematically gathered into a product dossier (PD). In line with an Investigational Medicinal Product Dossier (IMPD), this dossier should include information about the raw material, the final product, manufacturing procedures, quality control including used techniques, pharmacological data (dosage, administration route), pre-clinical toxicity data, clinical data, and a risk-benefit analysis. The PD is part of the documents submitted to the competent authorities. See Additional file 1 for the Product Dossier of the CARBON-study and Table 10 for the practical checklist.

Table 10 Practical checklist to prepare for clinical trials with non-medicinal investigational products
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Discussion and lessons learned

Research with non-Medicinal Investigational Products e.g. allergens, rhinoviruses, endotoxins, carbon nanoparticles and physiological substances such as lactate is challenging for investigators as well as members of competent authorities. An important reason is, that specific guidelines and regulations required for this type of research are lacking.

Therefore, we strongly suggest that investigators supply the Ethics Committee with a Product Dossier (PD), thereby providing standardised information about the required aspects of the non-Medicinal Investigational Product. This dossier comprises production, quality, and toxicological information about the raw material and the final product, and a risk-benefit analysis for the specific target group in the proposed study. Such a PD should be composed in collaboration with professionals equipped with product-specific and toxicological knowledge.

In light of the risk-benefit-analysis of the CARBON-study, we analysed whether carbon nanoparticles would be able to cause bronchoconstriction, pulmonary inflammation and coagulation activation to the study participants [20, 21]. We decreased these risks as much as possible by adjusting research design (escalating-dose), route of administration (localized, bronchial segmental deposition) and adjusting the dosages to relatively normal daily exposures. Naturally, safety endpoints were closely monitored and documented by the investigators and assessed by an independent Data Safety Monitoring Board (DSMB). (See Table 5).

Considering the accountability of the Ethics Committee, it is comprehensible that it has additional concerns, requests, and requirements to guarantee the safety of individuals. Fortunately, we were offered the opportunity to give further information during a face-to-face meeting with the Committee, which helped to take away major concerns.

Although we performed interim analysis after completion of each dosage-group, which was assessed by a Data Safety Monitoring Board, it would have been more conscientious if the Ethics Committee was also informed about the interim analysis. In retrospect, we also should have challenged one person per study day instead of two, in order to better monitor possible adverse reactions.

Another lesson we learned, is that the risk-benefit analysis should comprise information about pre-clinical toxicological studies on both the raw material and the final product. For the CARBON-study, there was pre-clinical toxicological information available about the raw product, but we omitted to perform these studies with the final product.

After thorough preparation, the CARBON-study was successfully completed, and showed that bronchial segmental challenge with carbon nanoparticles up to a maximum of 100 μg is safe and well tolerated.

Conclusion

In order to guarantee safety for study participants and to ensure credible research data and harmonisation of human interventional research, we have provided a point-by-point line of approach (summarised in Table 10) for clinical trials investigating non-Medicinal substances, including instructions on how to compose a Product Dossier for the Ethics Committee to assess. One should keep in mind that each non-Medicinal Investigational Product needs its own specific, multidisciplinary analysis. With this paper we intend to draw the attention of the public and government to this issue, in order to stimulate the implementation of this line of approach as common practice for human interventional research with non-Medicinal substances.

Abbreviations

API, active pharmaceutical ingredient; EC, European Commission; EMA, European Medicines Agency; EU, European Union; FDA, Food and Drug Administration; GCP, good clinical practice; GLP, good laboratory practice; GMP, good manufacturing practice; HSP, human subject protection; ICH, international conference on harmonisation; IMP, investigational medicinal product; IMPD, investigational medicinal product dossier; LPS, lipopolysaccharide; MA, marketing authorisation; Non-IMP, non-investigational medicinal product; Non-MIP, non-medicinal investigational product; PD, product dossier; QP, qualified person; TEM, transmission electron microscopy; TEM-EDX, transmission electron microscope-energy dispersive x-ray spectroscopy; WMA, World Medical Association; WMO, medical research involving human subjects act