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Final Remarks

In his closing remarks, Saverio Capuano singled out three major issues discussed at the workshop:

1. The lack of a global consortium to oversee an ethical way of supplying marmosets to support the increasing demand for their use in biomedical research;
2. The challenge to improve the understanding of the dietary requirements of marmosets while ensuring that diet does not affect the quality of research data; and
3. The challenge to understand and agree on methods to preserve the genetic diversity of captive marmosets.

More broadly, the workshop on Care, Use, and Welfare of Marmosets as Animal Models for Gene Editing–Based Biomedical Research provided a forum for open discussion of many facets of marmoset research. Panelists reflected on the history of and drivers for the use of marmosets in research, shared recent scientific findings, and discussed approaches used to care for and manage these unique animals in research facilities around the world.

Crucially, participants explored ways to ensure research conducted in marmosets is performed ethically. These include careful consideration of the values of the research community and the public, as well as the application of evidence relevant to assessing potential harms and benefits. Participants discussed a variety of practical steps that the research community could take to proactively guide research practices, enforce ethical behavior, and

facilitate productive public engagement that is rooted in a firm commitment to ethics and shared values.

Marmosets offer a number of unique advantages as research models. As NHPs their physiology reflects human physiology and disease processes more closely than rodents, yet they are easier to work with than other NHP species. Their small body size, short generation time and lifespan, and reproductive patterns make them ideal laboratory animals in many ways. In addition, specific features, such as a lissencephalic brain, make them better suited for certain types of studies.

These advantages, combined with a rapid expansion of genomic analysis capabilities and gene editing techniques, have led to an explosion in the interest in and need for marmosets as animal models. While marmoset research colonies have been maintained since the 1960s, recent years have seen a significant expansion in the depth and breadth of this work. Today researchers around the world use marmosets to study a wide range of basic biological processes and diseases, including neurology, aging, infectious diseases, reproductive biology, heart disease, cancer, genetics, microbiome research, and many other areas.

As research use of marmosets has grown, colony managers, researchers, and veterinarians have grappled with a dearth of evidence-based practices for the care and management of these animals. Even basic needs, such as determining practices for starting a new colony or obtaining sufficient numbers of animals to meet research needs, have presented challenges. The workshop served as a valuable platform for presenting evidence and sharing experiences relevant to routine care, colony management, and research practices.

However, the discussions also highlighted that much more work would further facilitate evidence-based practices and establish guidelines for the ethical and appropriate use of marmosets as animal models. Many attendees underscored the need for continued comprehensive and transparent reporting on marmoset care and use practices. Such reporting will be most beneficial if seen not as a competition between labs to determine whose practices are right or wrong, but as a collaborative means to investigate how different practices impact outcomes. This type of open exchange, which includes reporting negative as well as positive study results, can lead to even more insightful research questions and findings.

At the end of the workshop, presenters and attendees expressed strong enthusiasm for forming (or reinvigorating) committees and consortiums to gather new data and review available evidence to address remaining questions surrounding marmoset care, management, and use in research.