Industry Partner News: Audentes Therapeutics Announced the Beginning Development of New AAV-based Genetic Medicines for DMD

Dear Duchenne Muscular Dystrophy Patient Community,

Today Audentes Therapeutics announced that it is expanding its scientific platform and beginning development of new AAV-based genetic medicines for Duchenne muscular dystrophy (DMD). You can find the press release on our website under “investors/press releases” or directly at this link: https://audentestx.gcs- web.com/news-releases/news-release-details/audentes-therapeutics-announces-expansion-aav-technology

We are excited to share the news of our development programs with you and wanted to reach out to introduce ourselves and provide you information we hope you find helpful.

The Patient Advocacy and Engagement department is part of the Development team at Audentes. This means that we are in the same part of the organization as other functions such as Medical Affairs and Clinical Development. The Head of the Patient Advocacy and Engagement department is Kimberly Trant, and Chelsea Karbocus is a Senior Manager on the team. We have responsibility globally for patient-related advocacy and engagement activities. Our department is under the executive leadership of our Chief Medical Officer, Dr. Suyash Prasad, who is a pediatrician by background.

Who is Audentes Therapeutics?

• Audentes is a leading AAV-based (adeno-associated virus) genetic medicines company based in San Francisco, California

• Our focus is developing genetic medicines for serious, rare, neuromuscular conditions

• We have our own in-house cGMP (current Good Manufacturing Practice) manufacturing facility

• We aim to run robustly designed clinical trials efficiently so that we can achieve our mission of bringing innovative genetic medicines to patients living with serious, rare conditions as rapidly as possible

What experience does Audentes have in genetic medicine for rare neuromuscular conditions?

• Audentes began its first-in-human trial for X-linked myotubular myopathy (XLMTM) in late 2017

• This clinical trial uses a systemically delivered AAV vector to replace the MTM1 gene, which is responsible for producing myotubularin

• This clinical trial is still ongoing, and Audentes plans its next data update at the ASGCT conference in early May of 2019

What approach is Audentes planning to use for development in DMD?

• Audentes is collaborating with Nationwide Children’s Hospital to pursue an approach called “vectorized exon skipping,” which uses an AAV vector to deliver a genetic sequence designed to cause cells to “skip over” or ‘read-through’ faulty sections (or exons) within the genetic code. This is known as anti-sense technology

• This approach combines the proven delivery power of AAV to penetrate affected tissues with exon- skipping technology that regulates how a protein is produced

• The AAV approach is one which Audentes Therapeutics has expertise in, both in terms of clinical development and in manufacturing capability

• The exon skipping approach has precedence in DMD

• This approach aims to cause a production of a more complete, functional dystrophin protein which we believe will translate into clinical benefit

How does Audentes view the role of the patient community?

• Integration of the patient and family perspective is at the core of our work at Audentes

• We see the patient community as our partners, collaborators, and teachers

• We believe that patient perspectives should be integrated throughout the drug development process, from initiation of a clinical program to its completion and beyond

What is the goal of Patient Advocacy and Engagement at Audentes? Our goal is to deliver meaningful gene therapy clinical development programs, educational materials, and resources to support the rare disease community.

• Our priority is to weave the patient perspective into the fabric of our work and daily activities at Audentes

• We are here to advocate for you with our colleagues at Audentes

• To “advocate” is to support a cause or proposal. However, we believe that truly advocating for families requires much more than support. It requires commitment, dedication, and passion to ensure we are continually doing what is right for patients

We are honored to work with the Duchenne muscular dystrophy patient community and look forward to championing your perspective with our teams at Audentes. As we begin discussions with the patient community, we will be listening for and learning about the types of information and resources we can provide that are most meaningful and relevant to your needs.

For more information or to contact us:

• Please visit our website at patients.audentestx.com

• Send us an email at: patientadvocacy@audentestx.com

Sincerely,

Kimberly Trant, RN, MBA, Head of Patient Advocacy & Engagement
Suyash Prasad MD, Pediatrician, Senior Vice President and Chief Medical Officer