Regulatory Documents
We believe open source principles and practices benefit everyone. We are walking the walk of data sharing.

We share everything we learn in a way that everyone can understand and use. By “building in public” and “showing our work,” we share our resources and guidance for any and all.
One critical step on the road to sustainable precision medicine is the regulatory process. We pledge to publish as much of the Investigational New Drug application for leosen as we can.
IND for leosen
We are publishing our submissions to the FDA. This investigator-initiated IND was approved by the FDA in June 2023.
Some sections of the document are protected by IP which does not belong to us, so we are carefully checking each document and working to secure the support of all necessary partners to publish.
These documents were drafted for a specific ASO with LNA chemistry modifications. They may serve as a starting point, or template, for other investigator-initiated ASOs.
We thank leosen’s Principal Investigator Dr Nicole Coufal, MD PhD (UCSD/Rady Children’s), and our partners at Creyon Bio, for their support in joining us to make these initial IND documents available to the public.
If this helps your work
We offer this resource to help the families and patient advocacy groups who are pursuing a similar therapeutic strategy.
If this is helpful to you or your organization’s efforts, we ask that you acknowledge this in any publications, regulatory submissions, or other writing material — for example by including: “Consulting the leosen IND has helped in the preparation of this publication/document/article.”
For commercial and for-profit organizations, we humbly ask that you support these publications with a financial contribution. This will enable us to continue our work.
Get notifications when new documents become available
Email us and we will add you to the list. We will only write when a new document is published.

IND for SPG50 (AAV9 Gene Therapy)
ElpidaTx, a public benefit biotech led by a rare-disease parent, is also making its FDA documents available to the public for reference.

