In April 2025, the U.S. Food and Drug Administration (FDA) announced a groundbreaking plan: it will phase out the requirement for animal testing in the development of monoclonal antibodies and other new drugs (FDA Announces Plan to Phase Out Animal Testing Requirement for Monoclonal Antibodies and Other Drugs | FDA). This landmark decision means drug developers will no longer be strictly required to test new therapeutics on animals before moving to human trials, provided they employ proven alternative methods. The FDA’s move is designed to improve drug safety and speed up the evaluation process while reducing animal experimentation, a win for both patients and lab animals. FDA Commissioner Martin A. Makary called the initiative “a paradigm shift in drug evaluation” that could get safer treatments to patients faster and more reliably, while also lowering R&D costs and drug prices.
In a pivotal moment, the FDA answers long-standing calls from scientists and lawmakers to adopt more human-relevant testing methods.
Why is the FDA embracing new methods?
For over 80 years, drug safety testing has relied heavily on animals, from mice to monkeys, to predict how a drug might behave in humans. Yet animal models often do not predict human responses, and this process can be slow, expensive, and fraught with ethical concerns. Advances in science have now given us New Approach Methodologies (NAMs), which the FDA recognises can be more predictive and efficient. Instead of a blanket animal testing requirement, the FDA will encourage and accept data from NAMs, including computer models, lab-grown human tissues, and real-world clinical evidence. By leveraging these modern tools, regulators believe they can evaluate drug safety and efficacy with greater accuracy and speed. This approach does not just maintain safety standards, it has the potential to raise them, by using systems that reflect human biology more directly than animal tests ever could.
What exactly are these NAMs the FDA is championing? They encompass a range of innovative, human-focused techniques and technologies:
By integrating these approaches, the FDA expects multiple benefits. Drug development could become faster and more cost-effective (since lengthy animal studies can be trimmed down or eliminated), and the safety predictions more reliable for humans. Importantly, this shift also has an ethical dimension: it signals progress toward a future in which laboratory animals are no longer needed for routine drug testing. In the words of Commissioner Makary, it’s “a win-win for public health and ethics”.
The FDA’s announcement is a significant step forward, not only for regulatory science, but also for researchers striving to improve human health. At bit.bio, part of our mission has always been to advance human biology by providing access to defined, consistent human cells. These models are designed to help researchers generate insights that are more translatable to human patients, ultimately accelerating the development of new therapies.
Our mission to code cells for novel cures goes hand-in-hand with creating a future where drug development is human-centric from the start.
For decades, many scientists have relied on animal models or immortalised cell lines, not out of preference, but because better tools weren’t available. These models have played, and continue to play, an important role in biomedical research. But they also come with limitations, particularly when it comes to predicting human-specific responses. The FDA’s new roadmap acknowledges this challenge and marks a shift toward complementary, human-relevant tools that can support more predictive science.
bit.bio was founded on the belief that it should be possible to produce human cells that are consistent, scalable, and defined. When the U.S. Congress passed the FDA Modernization Act 2.0 in 2022, we recognised its significance: it opened the door to using cell-based assays as part of preclinical safety evaluations. The FDA’s announcement in April 2025 builds on that momentum by outlining a practical path for broader adoption of New Approach Methodologies (NAMs), a shift that aligns with the very technologies we have been developing and scaling.
By enabling routine access to human cell types with defined identity and function, we are supporting the scientific community in building models that are not only more human-relevant, but also more consistent and reproducible. Our focus is on helping researchers generate better data, data that can more effectively translate into meaningful outcomes for patients.
How is bit.bio contributing to this new paradigm, in practical terms? The answer lies in our unique deterministic cell programming approach, called opti-ox. This proprietary technology is a breakthrough in the field of synthetic biology and stem cell engineering. In simple terms, opti-ox allows us to take induced pluripotent stem cells (iPSCs) and program them into any desired human cell type, be it a neuron, a heart muscle cell, or a liver cell, in a matter of days. The process uses precise genetic switches to turn on specific genes so that the entire iPSC culture converts into the target cell type in a single step, with exceptional consistency.
Why is this important? Because for alternative methods to truly replace animal tests, researchers need access to high-quality human cells at scale. It is not enough to have a few cells in a dish, scientists need batches of cells that behave predictably, so experiments are reproducible and data are trustworthy. That is exactly what opti-ox delivers. It enables unlimited batches of human cells to be produced with the same defined identity, every time. For example, we can provide vial after vial of glutamatergic neurons (a type of brain cell) or skeletal muscle cells that are virtually identical in their properties. This level of standardisation is unprecedented; it sets new standards in biological research, as noted when we secured our U.S. patent for the technology.
With opti-ox, scientists no longer have to rely on variable primary cells or non-human cells for testing. They can instead work with human cells that are engineered to be consistent and ready-to-use. This has huge implications for drug discovery: safety tests can be done on human cells derived from opti-ox; efficacy screens can be run on disease-relevant human cell models, all before any human or animal is ever involved. Indeed, our opti-ox-powered ioCells™ product portfolio already offers researchers human cell types (like neurons, glia, and muscle cells) that come cryopreserved and standardised for fast use in experiments. These tools make it possible to model diseases in a dish and test drug candidates in a human context early on, which has the potential to greatly improve translatability of results. By overcoming the traditional bottlenecks of stem cell differentiation, we are providing the means to execute high-throughput screens and safety assays directly in human cells, something that was logistically difficult in the past.
In short, bit.bio’s opti-ox technology is a key enabler of the FDA’s vision. Regulators can call for NAMs, but those methods need to be robust. Our technology supplies the consistent human cells at scale that make NAMs like cell-based assays feasible on an industry-wide level. It is one thing to grow a small batch of cells for an academic experiment; it is another to manufacture them at the scale pharma companies require for drug screening. opti-ox bridges that gap. By providing an off-the-shelf supply of human cells, we hope to accelerate the adoption of animal-free testing methods across the biotech and pharmaceutical industries.
It is no coincidence that bit.bio finds itself at the forefront of this transformation. The FDA’s announcement represents a convergence of science, technology, and policy that we have been anticipating.
We have been partnering with forward-looking organisations to incorporate human cell models into drug development pipelines, for instance, in partnership with a major contract research organisation, our human disease models have already been integrated into early drug discovery screening workflows. Such collaborations are demonstrating in real time that human cell models can diversify the toolkit available to researchers in the pre-clinical phase, yielding data that are potentially more relevant to human patients.
"This is a watershed moment for our industry. We welcome the FDA’s decision as validation of what we’ve been working towards, creating scalable human cell models that are ready to support new approaches to drug discovery,” says Przemek Obloj, CEO of bit.bio. “For New Approach Methodologies to succeed, researchers need access to consistent, defined human cells, and bit.bio’s opti-ox technology is designed to meet that need. Our goal is to accelerate the shift toward more predictive research models, helping bring safer, more effective therapies to patients faster.”
As Przemek highlights, bit.bio views the FDA’s policy change not just as news, but as a clear mandate for innovation, a call to action we are prepared to answer. The FDA’s embrace of NAMs is a strong signal that the era of relying on animal models is waning. In its place, a new paradigm is rising: one built on advanced simulations, human cell models, bioengineered human tissues, and real-world human data.
The phase-out of animal testing requirements marks the dawn of a new era in drug discovery and development. For patients, it promises faster access to innovative treatments that have been vetted on human biology from the outset. For the scientific community, it offers a more efficient R&D process, where researchers can focus on human-relevant results and skip lengthy animal studies that often fail to predict clinical outcomes. And for animal welfare advocates, it is a long-awaited step toward ending the routine use of animals in laboratories, potentially sparing tens of thousands of animals each year as these new methods take root.
There is much work ahead to fully realise this vision. Regulators will be refining guidelines and verifying that these new methods are as rigorous and reliable as the old ones. The FDA has outlined a roadmap and even a pilot program to help companies transition to primarily non-animal testing strategies. It will be a gradual process, but the direction is clear. The regulatory landscape is changing, and it is doing so in a way that aligns ethics with state-of-the-art science.
At bit.bio, we are excited, and prepared, for this change. Our team will continue to advance our deterministic cell programming platform and expand the portfolio of human cell types available, so that whatever data a drug developer needs, there is a human cell model ready to provide it. We will also continue to work closely with the broader scientific community and regulators to demonstrate where our human cells can complement animal experiments most effectively. The FDA’s decision validates the path we are on. It reinforces that scalable human cell models like our opti-ox-powered cells are not just alternatives, but the new gold standard for preclinical research.
In conclusion, the FDA’s April 2025 announcement is more than just a policy shift, it is a signal of a paradigm shift in how we approach curing disease. By embracing NAMs and phasing out animal testing, the FDA is steering drug development into the 21st century, joining a broader international movement, with Europe also advancing toward more human-relevant, non-animal methods. This new approach will rely on technologies like computational modelling, organoids, and importantly, platforms that can produce human cells at scale. It is a watershed moment that aligns safety, efficacy, speed, and ethics in drug development. And it is precisely the moment that bit.bio has been built for, a future where human cell models drive discoveries. We are proud to be part of this revolution, coding the building blocks of life to advance the wellbeing of humanity.
Sources