Accelerated acceptance of 3R methods by involving all stakeholders

Project acronym: SLIM

Objectives: Enable economic development in Life Sciences by optimizing the implementation process of innovative 3R approaches by involving all relevant stakeholders during the development, acceptance and implementation of new 3R methods.

Key collaborations: Scientists (TNO, Univerisity Utrecht & Wageningen); Industry (Glaxo Smith Kline and Danone - Nutricia Research BV); Regulators (CBG, EMA, OECD); Government (RIVM, NKCA)

Funding: Ministry of Economic Affairs, Province and Municipality of Utrecht, and the individual partners

Relevant publications:
1. Schiffelers MJ, Blaauboer BJ, Hendriksen CM, Bakker WE. Regulatory acceptance and use of 3R models: a multilevel perspective. 
ALTEX. 2012 ;29 (3):287-300

2. Schiffelers MJ, Blaauboer BJ, Bakker WE, Beken S, Hendriksen CF, Koeter H, Krul C. Regulatory acceptance and use of 3R models for pharmaceuticals and chemicals: Expert opinions on the state of affairs and the way forward. Regul Toxicol Pharmacol. 2014 Feb 14. pii: S0273-2300(14)00031-2.

3. Knipping K, Simons PJ, Buelens-Sleumer LS, Cox L, den Hartog M, et al. (2014) Development of b-Lactoglobulin-Specific Chimeric Human IgEk Monoclonal Antibodies for In Vitro Safety Assessment of Whey Hydrolysates. PLoS ONE 9(8): e106025. doi:10.1371/journal.pone.0106025

Authors: Dr. Cyrille Krul, Dr. Marc Teunis, Dr. Laura M'Rabet.

Part of the text and art-work of this article has been produced by Tessa Louwerens Tekst & Beeld en




Watch the whiteboard animation summarizing the project.
During the course of the project several workshops and meetings were organized. Results of the public workshops and final symposium can be found below.
- Results and conclusions
Symposium SL!M project
- Transparantie; 'Van intentie naar actie’ 29th October 2013.
- The three Rs; ‘SliM in beeld’ 18th June 2013.

Main aims and objectives

 New medicines and food products should not only be proven efficacious in men, they are also subjected to strict safety regulations. Animal testing is still an important part of regulatory safety studies. Regulatory affairs and research & development are costly and time-consuming, which slows down innovation in the Life Sciences sector. Furthermore the predictive value of animal models is sometimes limited and newly available technologies are very slowly accepted and implemented. While on the other hand new European legislation and the general public opinion on the use of animal experimentation ask for other solutions. Therefore there is an urgent need to improve the innovation process.

The aim of the SLIM (‘Sneller van Innovatie naar Mens’) project is to enable economic development in Life Sciences by optimizing the implementation process of innovative 3R approaches; to reduce, refine and replace animal testing. SLIM aims to involve all relevant stakeholders during the development, acceptance and implementation of innovative 3R approaches.

Case studies

The SLIM project team focuses on developing and optimizing new test strategies for assessing the safety of a product that could accelerate product development and at the same time reduce the number of animal experiments. Currently we are working on four cases studies within different research areas; carcinogenicity, allergenicity, reproductive/developmental toxicity and barrier functions (pharmacokinetics). Two case studies focus on retrospective analysis of animal experiments and aiming to identify whether less animals could be used, without lowering the safety of new products. Another case study focuses on developing in vitro models to screen and identify compounds that could induce embryotoxicity or allergic reactions. The fourth uses different in vitro models to study intestinal absorption.  

Case study 1: Developmental toxicology : do we need two species?

To determine the safety of medicines and chemicals, developmental toxicity studies (e.g. fertility disorders and birth defects) are carried out in both rats and rabbits. This SLIM project uses retrospective data to determine whether it is necessary to carry out these studies in both species or if one species would suffice. One of the alternative methods that SLIM is exploring is the use of the Embryonic Stem cell Test (EST). The research that is taking place at the RIVM and Hogeschool Utrecht is part of an international consortium.

Case study 2: In vitro assessment of allergenicity of hydrolysates

Infant formulae, containing Cow’s milk hydrolysates, need to be tested for allergenic/sensitizing potential. A validated animal model is not available and guinea pigs are frequently being used. However, the guinea pig model is less suitable, giving false positive results and animal discomfort. Within the SLIM project, test are being developed using human mast cell assays in combination with protein analyses to predict allergenicity of hydrolysates. The project is taking place at HU, Bioceros and Universiteit Utrecht-IRAS.

Case study 3: Do we still need the 2 year rat carcinogenicity study?

New insights into the development of cancer might lead to the development of alternative test strategies for carcinogenicity studies. Using retrospective analysis of different classes of compounds (food additives, drugs, chemicals) this SLIM project aims to support an alternative strategy that could replace long-term animal tests (18-24 months) with shorter (3-4 months) tests, using considerably less animals. The research is carried out at TNO and Wageningen University & Research centre (WUR), in collaboration with the RIVM.

Case study 4: Alternative methods to determine bioavailability after oral ingestion

The potential toxicity of a compound is partially determined by the manner of ingestion and the subsequent distribution through the body. This SLIM project focuses on the question: Which alternative methods give a reliable indication of the bioavailability of a certain compound after oral ingestion? Predicting the in vivo bioavailability based on in vitro data and in silico modeling could significantly reduce the number of animals used. Alternative methods based on tissue culture and computer simulation should result in an international testing strategy for compounds with different chemical properties. The project is carried out at TNO, Universiteit Utrecht-IRAS and HU.

Collaboration and education

The development of these alternative strategies can only be accomplished by close collaboration between researchers, industry, government, industrial associations, animal welfare organisations and regulatory bodies. Various partners are involved in the project at the national and European level, each with different expertise that is needed to change and improve the acceptance and use of 3R methods. Lecturers (researchers) and students are involved in the practical development of the new 3R methods, e.g. as graduate projects. The participation of students is important to investigate the transferability of a method. Furthermore the results of the research activities can be included in the bachelor curriculum or can be part of post-graduate courses.  


We hope to continue the development of the 3R methods to an extent that these methods can be further validated and implemented in regulatory safety testing of new medicines and food products. Ideally the methods can also be transferred to other sectors like the chemical and cosmetic industry.

Related articles: 3R methods and koemelkallergie in een buisje (in Dutch)