Avidity Biosciences, Inc. (NASDAQ: RNA), a biopharmaceutical company committed to delivering a new class of RNA therapeutics called Antibody Oligonucleotide Conjugates (AOCs™), today announced that the U.S. Food and Drug Administration (FDA) cleared the company to proceed with the Phase 1/2 MARINA™ clinical trial of AOC 1001 in adults with myotonic dystrophy type 1 (DM1).

AOC 1001, Avidity's lead program utilizing its AOC platform, is designed to address the root cause of DM1 by reducing levels of DMPK, the disease-related mRNA. AOC 1001 consists of a proprietary monoclonal antibody that binds to the transferrin receptor 1 (TfR1) conjugated with a small interfering RNA (siRNA) that targets DMPK mRNA.

"The FDA clearance to proceed with our Phase 1/2 clinical trial for AOC 1001 is a significant milestone for Avidity as we move into the clinic with our first AOC engineered to deliver to skeletal muscle," said Sarah Boyce, president and chief executive officer. "We are grateful to Dr. Johnson for joining us on today's call to discuss the current treatment of people living with DM1 and the important research that he and the Myotonic Dystrophy Clinical Research Network are conducting to further understand this progressive disease. We are continuing to engage with the DM1 patient, advocate and physician community as we actively work to get the trial up and running."

The MARINA™ Phase 1/2 Trial of AOC 1001 in Adults with DM1 and Recent Highlights

The MARINA trial is a randomized, double-blind, placebo-controlled, Phase 1/2 clinical trial expected to enroll approximately 44 adults with DM1. The primary objective of this study is to evaluate the safety and tolerability of single and multiple ascending doses of AOC 1001 administered intravenously. The MARINA trial will assess the activity of AOC 1001 across key biomarkers, including spliceopathy, a key biomarker for DM1, and knockdown of DMPK mRNA, the disease-related mRNA responsible for DM1. Though the Phase 1/2 trial is not powered to assess functional benefit, it will explore the clinical activity of AOC 1001 including measures of mobility and muscle strength as well as patient reported outcomes and quality of life measures. Patients will have the option to enroll in an open label extension study at the end of the post-treatment period. In the second half of 2022, Avidity plans to conduct a preliminary assessment of safety, tolerability and key biomarkers in approximately half of the study participants.

Recently, the FDA also granted Orphan Drug Designation to AOC 1001 for the treatment of DM1. The FDA grants Orphan Drug Designation to novel drugs that seek to treat a rare disease or condition and, if the drug is approved for the designated orphan indication, provides 7 years of market exclusivity, along with certain financial incentives, including tax credits, opportunities for grant funding towards clinical trial costs and FDA user-fee waivers.

Today's Video Webcast Information

The company is hosting Volume 2 of their virtual investor and analyst series today August 2, 2021 beginning at 8:30 am ET to further discuss the AOC 1001 program. The event is a live video webcast and can be accessed here or from the "Events and Presentations" page in the "Investors" section of Avidity's website. A replay of the webcast will be archived on Avidity's website following the event.

The management team will be joined by Dr. Nicholas E. Johnson, MD, MSCI, FAAN. Dr. Johnson is one of the principal investigators in END-DM1, an ongoing natural history study being run by the Myotonic Dystrophy Clinical Research Network (DMCRN) and will be the lead investigator in the Phase 1/2 trial for AOC 1001. Dr. Johnson is an associate professor, division chief of neuromuscular, and vice chair of research in the department of neurology at Virginia Commonwealth University.