Cardiac Organoid Platform Co-Developed in Vienna Validated for Early Drug Development and Derisking

1.From Embryo Question to Beating Model

The cardioids originate from Sasha Mendjan’s group at the Institute of Molecular Biotechnology (IMBA) at the Vienna BioCenter, which studies how a human heart develops during embryogenesis. In 2021, the team reported that, under the right conditions, human stem cells spontaneously organize themselves into a beating, chamber-like structure with a cavity. This initial model replicated a single structure: the left ventricle.

In their following publication, they reported on expanding the model by developing organoid models of individual heart structures and growing them individually, after which they asked, as Mendjan put it:

“If we let all these organoids co-develop together, do we get a heart model that co-ordinately beats like the early human heart?”

In the resulting multi-chamber cardioids, the electrical impulse spread from the atrium to both ventricles, just as in the early fetal heart. This gave researchers unprecedented insights into the development of the heart during embryogenesis and how the heart starts beating.

2.Why Drug Testing Needs Better Heart Models

The development of the cardiac organoid platform was not only valuable for helping scientists understand biological processes that occur during the formation of the heart. Heart damage is one of the main reasons why many potential drugs fail to reach the public.

Currently, cardiotoxic effects are often tested using cell cultures or animal models, but both methods have limitations when it comes to accurately predicting how a new drug may affect the human heart, particularly during embryonic development. Cardiac organoids could provide a more reliable and human-relevant model for studying drug-induced heart damage and assessing potential risks during drug development.

3.From Spin-off to Validated Product

In May 2021, HeartBeat.bio AG was founded as a spin-off from IMBA, with an exclusive license to the technology. The founders include Mendjan himself and Pablo Hofbauer, the first author of the 2021 paper. Since September 2022, the company has been developing the platform in collaboration with Molecular Devices, a California-based manufacturer of laboratory automation and imaging equipment.

Recently, the two companies announced their first joint product, a 3D Ready Cardioid Supplement Kit, available from autumn 2026. On 10 August, they reported that the Milan-based company Axxam had successfully validated the kit. Axxam is a contract research organization that tests substances for pharmaceutical companies. Axxam and HeartBeat.bio had announced a strategic partnership in July 2026, in which Axxam integrates the cardioid platform into its own discovery services. The validation is therefore external to the manufacturer, but not conducted by an uninvolved party.

4.Outlook: What Basic Research Delivered

Axxam confirmed the workflow at both the phenotypic and the functional level. On that basis the company is integrating the platform into its own translational research services, where it can be used to model cardiovascular disease and drug development. For HeartBeat.bio, seeing the technology run successfully by a drug discovery provider is a step toward establishing human cardiac organoids as a routine tool for disease modeling and safety assessment, rather than a method that only works in the laboratory that invented it.

Cardioids are an example of what basic research can achieve. What began as a question about the development of the heart has evolved into a product that laboratories and companies worldwide can order. How much it will change the way drugs are tested remains to be shown.