A vision for animal-free drug testing

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Tamara Zietek, CEO of Doctors Against Animal Experiments


A vision for animal-free drug testing

This month, we sat down with Tamara Zietek, a pioneer in 3D intestinal modelling and, now, a leading voice pushing for replacing animal testing in life science with New Approach Methodologies (NAMs). We discuss her journey, the evolution of in-vitro 3D models, regulatory hurdles, and how we can achieve a paradigm shift in drug development.

Dr. Zietek started her life science journey in biochemistry at the University of Bochum in 1999. In 2010, she joined the Technical University of Munich as a Principal Investigator for the Nutritional Physiology Department. Her main research focus was the link between nutrient absorption and incretin hormone secretion. 

She has worked with every available model system, from 2D cell lines to animal models. Dr. Zietek realised that there were major translational (and ethical) problems with using cell lines and animal models. 

Dr. Zietek was inspired by research done on intestinal organoids by Hans Clevers. The 3D in-vitro system had both endocrine and enterocytes, which was difficult to achieve with 2D co-cultures.  

She went on to establish 3D organoid models in her group. She was one of the only ones working with these models in Germany at the time.  

Driven by her belief that 3D culture is a better scientific and ethical alternative to animal testing, Dr. Zietek left academia in 2018 to join Doctors Against Animal Experiments (DAAE). 

Today, she is the newly appointed CEO of DAAE. She works with key stakeholders in the EU to move the industry toward an animal-free future.

Eliminating animal testing in life science 

Describe the work that you engage in with DAAE. 

Dr. Zietek: Our NGO has different parts. We have public relations and campaigns. All the classic NGO things that you do because we are representing people who have an interest in replacing animal experiments. The science department is a team of 6 people. We write articles, have a very extensive website with a lot of information on non-animal New Approach Methodologies (NAMs). 

We work with the European Commission, with ECHA, and other agencies. They want to have a road map for non-animal testing which all resulted from the European Citizens' Initiative (ECI) that we initiated with others international partners. The ECI resulted in actions that the European Commission is willing to undertake or to support to accelerate the transition to non-animal testing. This is what we are working on a lot. 

There are also applied science projects. For example, the MPS World Summit or the International Microphysiological Systems Society (IMPSS) which formed during the last 2-3 years. This is where I'm also quite involved because I'm a member of the Scientific Advisory Board. 

These societies are important to show that we have better alternatives. We do have them. And you can see them because the best researchers worldwide present their models. Key academic and regulatory stakeholders, like the FDA and OECD, are also involved. We have all stakeholders on a global level. 

In the end, the prime focus isn’t even on finding animal alternatives. It’s clear we want to achieve that. But it’s more about better science, better safety, human-relevant science, lower failure rates, and better safety for humans.

Dr. Tamara Zietek

The ONTOX project is an EU project under the Horizon 2020 funding. I’m also doing some stakeholder work there. We’re developing NAM-based strategies for animal-free safety testing of chemicals. 

We have projects like our Non-Animal Technologies (NAT) database, which has around 2000 entries of non-animal methods all over the world. We are constantly working on it and we will have a webinar series for companies working in the NAM field as well. 

We are currently working on a systematic review that analyses clinical failure rates. We are seeing that in the last sixty years the failure has been around 92% and this is not improving. And preclinical trials largely contribute to this failure rate because safety and efficacy testing is not well reflected in the preclinical phase by animal experiments. 

Complexity vs. scalability of 3D culture

If 3D culture is better than 2D, why haven't they been fully adopted yet into pharmaceutical workflows for drug development? What are the big obstacles that are still preventing wide-scale adoption? 

Dr. Zietek: There was a 3D organ model conference in London and this question was discussed. We were talking about the scalability of organ models versus complexity. 

If you want to have a 3D model, why do you want to have a 3D model? 

Because it better reflects physiology. 

The thing is, do you need this complexity for everyone? I think that's not the case. 

There are so many stakeholders and so many disciplines involved in these technologies. Some need more complexity, others don’t. There is space for every model. I think we need models that are very complex if we want to do disease modelling, for example.  

But we also need models for high throughput where you screen hundreds of samples continuously. And that is where a complex 3D brain organoid model would struggle. You might just need a simple spheroid culture. We have excellent models in this field, neurospheres, that you can use for testing that will hopefully be accepted by OECD soon. 

So this is then what industry might need, because the models need to be reproducible, valid, and robust. 

If you have complex organoid models, they’re different depending on the donor. They have different characteristics which produce different results. Of course this is a chance for personalized medicine. Roche is big in this field. You will see that there is a future for these complex models. Roche is developing in a new institute in Switzerland for human biology. They have the best researchers in the world at this centre developing the most complex models. So there is a need for these models.  

But there is also a need for these less complex, more robust, more high throughput compatible models that are good enough to show that something is safe. You might only need certain organs. You might only need a certain pathway.  

I'm totally in favour of complex. This is still the academic researcher in me who will never die. 

The more complex the cooler. The closer to in-vivo physiology. Plus, there is enough space for every model and that's what we showed. 

I remember there was this paper on this ten-organ chip, a few years ago, and they talked about the whole body on a chip concept. 

This is also useful, but maybe a company like AstraZeneca or any other pharma company would rather have a three-organ chip. Why? Because 10 organs are too complicated or too costly. Or maybe they only want the relevant organs for a certain drug. A drug for a certain heart disease, for example, might not need skin on-a-chip. 

Photo by Christian Lue on Unsplash 

A paradigm shift in life-science regulation 

What are regulatory bodies saying? 

Dr. Zietek: Our regulatory system has been based on animal testing for a very long time, and it’s huge. It’s not easy to change things. We will have to change a lot to replace animal experiments. We need to change the entire regulatory framework. 

You don't have the same endpoints. For example, you can't look at increase in liver size, but you can look at adverse outcome pathways (AOPs). You can look at molecular markers which can be an even better approach to assess certain toxicity. 

So you need new endpoints. You need a combination of NAMs. Also, the fact that people used to talk about a one-to-one replacement. Replacing a certain animal test with a single in-vitro method. 

That this is not the solution. You cannot do that, and we will not do that. It will be batteries of NAMs. This is what will happen. 

We have approaches like IATA (Integrated Approaches to Testing and Assessment), and next-generation risk assessment (NGRA) that combine Omics, KI, in-silico, in-chemico, and in-vitro, etc.  

But this needs to be human based. 

Because what would you do if your NAM-based testing showed you that a drug is safe and then a certain animal test in a mouse showed toxicity? 

There are ways to get there, but we need to create confidence. And this is one of the central issues that we are working on. We are working to create confidence. 

It seems that we need to map what combination of NAM experiments we could do that would give us the same, or better, indication as certain animal tests. 

Dr. Zietek: Yes, we need whole approaches that have in vitro, organoid models, and organ-on-a-chip models and combine this data with computational analyses.  

What is an end point for? 

It’s to be certain that something is, for example, not toxic for reproduction. 

You can take mouse models and you can do cruel experiments on them, but they won’t be very reliable because the reproductive system is highly species specific. We have better human endometrium in-vitro 3D models. And these should be part of the pipeline. They should be part of the testing. 

The problem that the industry has is a company will submit a NAM-based dossier, let's say to ECHA or EMA. And then the agencies say that they still would like to have some animal experiments to be performed during the registration process. 

Final thoughts? 

Dr. Zietek: The most important thing is that that we realize that non-animal methods and 3D culture enable safer testing and better disease modelling for humans, and they make more economic sense. 

This is an innovative field. The EU should focus on these technologies and promote them because there’s a big market. 

These are the technologies of the future. 

Read Dr. Zietek’s full interview here. 

Want to connect with Tamara? 

You can find her here: 

LinkedIn: Tamara Zietek


NAT Database

DAAE’s Non-Animal Testing (NAT) database contains information on nearly 2000 cutting-edge non-animal technologies in life science. It received the LUSH prize 2022 in the Training category. 

It’s a hub for researchers, SMEs, and industry to connect with like-minded professionals in the field. Users can search for other people working with certain technologies, fields of research, or biological models.  

Or, if geography is important, filter by location. 

The platform facilitates collaboration between technology developers and scientists in academia and industry.  

To reach a paradigm shift in drug development, we need to work together.  

Become a member or find a NAT partner here. 

Photo by Tom Hermans on Unsplash 


Here are a few other great newsletters focused the field of 3D culture to keep you up to date on the most recent advances in technology & biology: 

Happy reading! 

Cool research in the field of 3D cell culture that you think would benefit the community? Reply to this email to discuss featuring it in our next issue.


Don’t miss out on these upcoming events in the 3D cell culture space:

Advances in Cell-based Screening in Drug Discovery 2024 (Gothenburg, SWE |15-16 May, 2024)

A prominent event hosted by ELRIG UK focusing on the latest innovations in cell-based screening techniques for drug discovery.

This conference gathers industry leaders and experts to discuss advances in high-throughput screening, novel assays, and automation technologies. It's a key platform for exploring new methodologies in cell biology and their application in identifying effective therapeutics.

For more information, visit the event page.

SLAS Europe 2024 (Barcelona, Spain |27-29 May, 2024)

A premier event organized by the Society for Laboratory Automation and Screening (SLAS). This conference is dedicated to the latest in laboratory technology, including automation and screening advancements.

For more information, please visit their event page.

MPS World Summit (Seattle, USA |10-14 June, 2024)

This conference is dedicated to the latest scientific achievements and bioengineering breakthroughs by pioneers in the MPS field. The event is organized by the International MPS Society.

For more information, please visit their event page.

That’s it for this month!

See you again in June.

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