Our 3Rs commitment

The 3Rs are at the centre of our commitment to good science and the responsible use of animals. We work continuously to reduce, refine and replace animal studies across our research activity.

Wherever possible, we use non-animal methods such as cell culture, computer modelling and high-throughput screening that eliminate the need to use animals early in drug development, or reduce the number needed. As part of our drive for continuous improvement, we use best practice in experimental and statistical design to optimise our studies and ensure the appropriate number of animals is used. We also work to refine our existing animal models to ensure that the animals are exposed to as little pain and distress as possible.

All our animal studies are reviewed on an ongoing basis to make sure that they continue to add value to our research decision-making processes.

Sharing and recognising best practice

Advances in 3Rs are shared across the company, so that our researchers can learn about and adopt practices and ideas that are consistent with their research needs. We also work within the wider scientific community to share 3Rs knowledge and experience.

Our global 3Rs Award is one of a range of scientific innovation awards given to employees demonstrating best practice in the research and development of new medicines. The Award is judged by a committee of our senior scientists and other staff from across AstraZeneca. In 2013 six entries were reviewed, and the global award was made to a team in our biologics division of the business. AstraZeneca shares these innovative techniques externally as well through trade associations such as the European Federation of Pharmaceutical Industries and Associations (EFPIA); the National Centre for the Replacement, Refinement and Reduction of Animals in Research (NC3Rs); and through Peer Reviewed Journals such as PLoS One.

Link to the 2014 EFPIA 3Rs report

Link to the Link to the NC3Rs website

Link to the PLoS One Article

Examples of our 3Rs commitment


Capillary microsampling brings dramatic global 3Rs advances

AstraZeneca is leading the way in developing and using capillary microsampling (CMS) to reduce and refine the use of rodents in toxicological studies.  The new CMS method collects and analyses very small, exact volumes of liquid blood or plasma, enabling robust toxicokinetic data to be obtained using up to 10 times less blood per animal compared with conventional methods.

CMS is an important welfare refinement, making blood collection quicker and less stressful for the animals, and causing them little or no physiological effect, because only a droplet of blood is taken.

CMS also brings other, previously impossible, advantages in rodent studies.  In the past, drug exposure data (showing how a potential new medicine is broken down by the body) had to be obtained separately from toxicological (safety) data, using extra (satellite) groups of animals – because combining the two would require too much blood to be taken from an individual animal.   Now, since CMS involves much smaller volumes, both sets of data can be obtained using blood samples from the same animals.  The benefits are two-fold:

  1. CMS enhances the scientific value of the data, because toxicological evaluation can now be related directly to drug exposure in the same individual animal, and
  2. CMS enables large-scale reduction in the use of rodents, by making satellite animals redundant for most studies.

CMS is now accepted as the method of choice and is implementation is progressing across AstraZeneca Global Safety Assessment and DMPK and its key CRO. For a typical one month tox study there is the potential to reduce use of rats by 15% and mice by 40% and bringing knock-on savings in the financial costs and time needed to complete each study.

Spheroids: a new in vitro alternative in fish ecotoxicology

As an alternative to the use of live fish, scientists at AstraZeneca's Brixham Environmental Laboratory (in association with academic partners at the Universities of Plymouth and Birmingham, and Kings College London) have developed an innovative cell-based method for evaluating the environmental effects of pharmaceuticals and other chemicals.

The new method involves gently 'stirring' fish liver cells in culture, so that they aggregate in tiny balls known as spheroids, which closely mimic key functions of intact fish livers.

Testing on spheroids has the potential to replace more than 300 fish used per compound in bioaccumulation tests.  Or, by batching compounds and fish, liver cells from just one fish could take the place of around 750 live fish in these studies.

a trout liver spheroid

Scanning electron microscope image of a trout liver spheroid taken at Plymouth University

Regulatory required bioaccumulation tests assess whether chemicals that enter the aquatic environment can accumulate in fish tissues, and take more than 4 weeks to complete.  Traditional fish liver cell-culture methods are not suitable alternatives because the cells stay healthy for only 4 days.  But spheroids thrive and maintain liver functions for around 40 days – making them strong candidates to reduce and replace the use of live fish in these studies, and in future perhaps other toxicological tests too.

The Brixham team is now working towards validation and regulatory acceptance of the new method, which is one of a long line of 3Rs innovations made by AstraZeneca’s Brixham Environmental Laboratory over the past 20 years.

Reducing the use of rats in male fertility studies

A team from AstraZeneca Global Safety Assessment at Alderley Park, UK, has developed, validated and promoted a better method for identifying potential effects of new medicines on male fertility.

Rather than carrying out traditional standalone fertility tests, the approach combines male fertility assessment with 6 month general toxicity studies, so sparing around 80 male rats for every compound tested, down from 140 to approximately 60 males.

The combined approach also provides richer, better integrated data thereby improving the risk assessment of longer-term effects on fertility, and better supports the development of medicines for adolescents as well as adults.

The validation of AstraZeneca’s approach, is described in a 2012 publication1 and this design option has been accepted as meeting international guidelines (ICHS5(R2)2005) for small molecules.

Reducing the use of non-human primates in safety evaluation

An alternative approach for testing the safety of three new monoclonal antibody medicines designed to combat infectious diseases resulted in a 57% reduction in the use of non-human primates, as well as cutting combined development time by 18 months and saving around $1 million.

The new medicines target two highly problematic antibiotic-resistant bacterial infections, and a virus that can cause severe respiratory illness in at-risk infants.

Monoclonal antibody therapies have highly specific modes of action, and for this reason non-human primates are often the only suitable animal species for testing whether they are safe enough to enter human trials. It is always an ethical imperative to minimise the use of animals, and the new approach has been disseminated across the company so that it can be implemented in all relevant testing programmes.

New in vitro approaches to evaluation of cardiac safety are greatly reducing the use of dogs in early pharmaceutical development.

Pioneering work by AstraZeneca safety pharmacologists has greatly reduced the number of dogs needed to provide heart cells for in vitro (test-tube) studies to screen potential new medicines for adverse side effects on heart function.

In the past, AstraZeneca used Purkinje fibres (specialised tissue that helps to synchronise heartbeat) for these tests, and hearts from four or five humanely killed dogs were needed to obtain enough fibres to test a single compound. Now, AstraZeneca’s new approach requires just one dog to obtain millions of heart muscle cells (myocytes) that can be used to screen many compounds.

Until recently, a major limitation was that healthy myocytes could only be maintained for 24 hours. But in 2011/2012, AstraZeneca scientists made a breakthrough that enables them to keep the myocytes healthy for about 2 weeks, meaning that many more compounds can now be tested using cells supplied from a single dog. Publication in the Journal of Molecular and Cellular Cardiology 64 (2013) 108-119 of the AstraZeneca method for preserving the myocytes will ensure that it can be used around the world, so making a global contribution to the 3Rs.

Further 3Rs benefits are now in sight, as the AZ team is making rapid progress towards greater reduction and potential elimination of the use of dogs for this purpose, by:
(1) developing computerised mathematical models for predicting the effects of new compounds on myocyte function, based on data accumulating from studies using cells; and
(2) validating the use of human stem-cell derived myocytes instead of dog myocytes.
Again, the new methods are being published in full, so that they can be used by scientists worldwide.

1 Assessment of male, rodent fertility in general toxicology 6-month studies. Birth defects research (Part B) 95, 410-420


Refining and reducing the use of large animals in cardiac safety assessment

Our safety assessment team has co-developed, validated and championed the use of an external telemetry (radio-transmitter) method to assess the effects of potential new medicines on electrocardiogram (ECG – a study of heart function) in dogs. The new method reduces the adverse effects caused to the dogs, enhances the value of the scientific data obtained, and helps to avoid the use of around 120 dogs annually across AstraZeneca.

External telemetry involves placing recording pads on the animal's chest, with the recording leads attached to an external radio-transmitter, all held in place by a specially designed jacket. The dogs are able to move freely around their pens whilst the ECG is continuously recorded. The external method is replacing more conventional studies, in which the dogs are restrained in harnesses for 30-second 'snap-shot' recordings of ECG.

Because it avoids restraint, the new method is an important refinement that greatly reduces the stress caused to the dogs. Moreover, by enabling continuous recording, the method enhances the value of ECG data that can be collected early in the drug development process – for example, determination of the time course, magnitude and reversibility of any changes in ECG and better detection of low incidence effects. This has enabled earlier identification and discontinuation of compounds likely to affect heart function, thereby avoiding further animal studies; and has eliminated the need for stand-alone safety pharmacology studies to assess chronic effects of potential medicines on ECG involving animals with surgically implanted telemetry devices. As a result, it is estimated that the new approach has helped to avoid the use of around 120 dogs a year across AstraZeneca.

The team's work has also lead to acceptance of external telemetry as the preferred approach for similar studies involving non-human primates, where it looks set to deliver even greater scientific and animal welfare benefits.

Reducing the use of non-human primates

Our scientists brought a new monoclonal antibody medicine to clinical trials on the basis of in vitro data and information from extensive testing involving genetically altered mice, avoiding the use of non-human primates. The data satisfied regulatory authorities in the US, Canada and EU that the compound is sufficiently safe and effective to be tested on patients.

This provides important 'proof of principle' that approval for clinical trials of mAbs may be possible without including data from studies in non-human primates. It is hoped that the new mAb will become an important treatment for potentially life-threatening cancers, such as lymphoma and leukaemia, and certain auto-immune diseases.

Note: Monoclonal antibody (mAb) medicines are highly specific to their intended molecular targets in the human body. Similar targets are often found only in other primates and so non-human primates are usually the preferred species for pre-clinical testing of new mAbs. However, in this case our team took an alternative approach, using mice that had been genetically altered by inserting a human gene that enabled them to express the exact human targets for the new mAb. Mice from the genetically altered colony will remain available for future studies, and have already been used to help in the development of another similar molecule.


  • Our scientists have pioneered, developed, and validated the use of a combined telemetry and automated blood sampling system in rats. This allows effects of potential new medicines to be measured on a wide range of bodily functions simultaneous with blood sampling and urine collection. This enables information on changing levels of a compound in the bloodstream to be matched with its effects on bodily functions (e.g. heart-rate, blood pressure, body temperature, EEG and renal function) in the same animal. In the past, these sets of data have had to be recorded separately, in different groups of rats, requiring more animals. By recording these aspects simultaneously from the same animal, the new system has enabled a significant reduction in the number of rats used to select the most promising compounds for further development. Most importantly the data (based on levels of stress hormones) indicated the integrated system was no more stressful to the animals than previous methods.
  • Our scientists have reduced and refined the use of non-human primates to test the safety of monoclonal antibody therapies during pregnancy. Through careful and critical evaluation of conventional testing methods, they have developed a new study design that reduces the number of non-human primates by more than 50% (down from over 100 to around 40 for each new therapy. The team has won the international regulatory authority’s confidence in their new design, which is now cited as the preferred approach, on both scientific and animal welfare grounds. Importantly, the team has successfully lobbied for the tests to be done at a much later stage in the drug development process and so further reducing the use of non-human primates.Monoclonal antibodies are highly specific to human physiology, so non-human primates are in most cases the only relevant animal model to use because of their similarity to humans. However the decision to use this animal species is always made on a case by case basis taking into account all possible alternatives.


  • The 3Rs award went to a team of scientists who validated a complex computer-controlled mechanical and chemical model of the upper part of the human digestive system (stomach and small intestine) for use in formulation development (the process of deciding how best to combine new medicines with other ingredients to ensure they can get to where they are needed in the body at the appropriate concentration). At AstraZeneca in the UK, pioneering use of this simulation has virtually eliminated the small number of dogs needed to develop formulations of medicines for cancer, inflammation, infection and cardiovascular disease.
  • AstraZeneca scientists in Boston have made a number of refinements to pharmacokinetic (PK) studies involving rats. These have enhanced animal welfare, reduced the number of animals used, and improved the scientific value of the data obtained. The refinements include changes to blood sampling procedures, and development and validation of a novel method of sequential dosing. Overall, these changes have led to a 50% reduction in the use of rats in PK studies at this site.
  • A specific study in rodents used to test side effects for new medicines on the digestive system (e.g. constipation and diarrhoea) have undergone considerable refinement at AstraZeneca. Typically, animals have their food withdrawn overnight (around 18 hours) prior to testing, so as to reduce variation in results. However, our scientists have shown that, although a period of fasting is still needed, reducing the time to 6 hours greatly improves animal welfare without compromising scientific validity. A 6-hour fasting time is now used in the UK, during the daylight phase when food intake by rodents is minimal, benefiting many animals. AstraZeneca scientists using other tests that require fasting are also evaluating this refinement.
  • Our respiratory and inflammation research area (RIRA) has reduced the use of animals in tests needed to support products that combine two therapeutic agents in an effort to bring potentially improved treatments to patients. They have shown that tests on live guinea pigs are not needed for this purpose; and that, instead, in vitro (test-tube) studies using guinea pig tissue can successfully demonstrate the additional benefit of combining two compounds. With the need for future combinations to be evaluated, use of these more clinically relevant alternatives will significantly reduce the number of guinea pigs needed in RIRA - with tissue from just four guinea pigs needed per combination instead of up to 160 live animals.)
  • AstraZeneca scientists have refined and reduced the use of rats in studies carried out to identify compounds that might be used to treat obesity and associated type-2 diabetes. The new method requires 40% fewer animalsand yields results directly applicable to humans more quickly. This work was presented at ’The 3Rs Today’, an event hosted by the UK National Centre for Replacement, Refinement and Reduction of Animals in Research, where it won the reduction prize. Find out more about the National Centre for 3RS.


  • Our 2008 global award for best practice in 3Rs was made to the scientist who led a European collaborative project, involving 18 pharmaceutical companies and contract research organisations, which demonstrated the limited value of specific single dose acute toxicity studies in pharmaceutical development. The studies were a regulatory required test ahead of first administration of a new medicine to humans. The project demonstrated that this is not necessary, because the information required to assure human safety can be obtained from other, more refined animal studies. As a result of this work, AstraZeneca has not conducted such studies since 2006 and other companies are also taking up this approach, which has led to a collective 70% reduction in the use of rats and mice for these studies across Europe (approximately 15,000 animals each year). The output of the work is now leading to revision of international regulatory guidelines so that these animal tests will no longer be required. Following the success of this project, a similar approach is now being used to examine the need for acute toxicity tests in other sectors (e.g. veterinary medicines and chemicals used in agriculture). AstraZeneca is again taking the lead, co-ordinating an acute toxicity team under the umbrella of the European Partnership on Alternative Approaches (EPAA).
  • In the US a project is underway to ensure that, wherever possible, tumour tissues from mice used in cancer studies are not discarded, but are collected and stored for further use. The resulting enhanced tissue bank provides our scientists with linked protein, RNA and tissue from a wide range of tumour types, enabling them to make early, rapid, and comprehensive assessments of potential new treatments for cancer, without the need to generate additional tumours in mice. In 2008, samples of 200 different types of tumour were submitted to the bank and 24 different AstraZeneca projects were supported in the US, UK and China, directly sparing up to an estimated 7500 mice that would otherwise have had to be used to generate the tumours. A database linked to the tumour tissue bank also went live in 2008, further increasing its scientific value. In the future, these benefits are set to increase as more tumour samples are added to the bank and the database of scientific information gained from using them grows.


  • We increasingly use non-invasive imaging techniques such as ultrasound and MRI (which are also used for human diagnosis) to study the effects of new medicines on the progress of disease in living animals. Our scientists have been instrumental in developing an innovative ultrasound method that enables them to “look inside” a mouse’s arteries and follow the effects of potential medicines on the development of atherosclerosis in “real time”, in the same animal, over its whole life. This method helps to improve the scientific accuracy of the studies, and reduces the number of animals needed to obtain the required data.
  • Databases that capture information on the properties of existing medicines and other similar compounds can help scientists to predict, at an early stage, how new compounds are likely to behave in the human body. This enables earlier, more informed choices about which compounds to take forward for further development – which in turn helps to avoid any unnecessary animal testing on compounds likely to fail. We use a range of such databases, and in 2007 increased predictive power by rolling out across all sites the most comprehensive pharmacological profiling database currently available – Bioprint®, licensed from Cerep.


  • We use in vitro hepatocytes (liver cell) tests to assess how a compound is eliminated from the body, allowing us to discard unsuitable compounds without the need for animal studies. We have also developed an automated test for rat hepatocytes, the accuracy of which is proving less variable than the previous manual assay. These efficiencies mean that at this stage of research, we can test more compounds and make compound selections without the need for animal studies.
  • Our use of synthetic animal protein in drug development means that some techniques which required the use of animal tissue have been replaced, and the predictability of the animal studies that we must still do has been improved, leading to the use of fewer animals overall.


  • We use leading-edge computer technologies to predict more accurately how a potential medicine may act in the human body (for example, how it will be absorbed and distributed). This enables elimination of unsuitable compounds early in the discovery process and stops their progression into animal studies.
  • New medicines for arthritis aim to relieve pain and improve mobility. We use a new system of imaging and analysing how an animal with arthritis walks so that we can immediately detect any subtle changes in mobility following treatment. This is a major welfare improvement as the study is less stressful for the animal and can provide more accurate data using a smaller number of animals.
  • A European project, initiated by AstraZeneca, could more than halve the 1.6 million fish used in environmental safety tests in Europe. Subject to regulatory approval, initial testing of chemicals will be undertaken with algae and water fleas (daphnia) to predict the threshold of toxic concentration. This will then limit the number of concentrations that need to be tested in fish, and so reduce the numbers used.

What's next in this section

Our performance

Details of our performance in 2013.

Read more

3Rs of animal research


Use alternatives to animal testing wherever possible


Improve existing methods so fewer animals are required.


Refine existing methods so animals are exposed to as little pain and distress as possible.

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