This presentation will focus on similarities and differences between recently approved US and ex-US commercial applications for ASOs. High-level information covering the CMC regulatory strategies and submission content among countries will be discussed, along with similarities and differences between health authority requests.

AstraZeneca’s global CMC regulatory experience across clinical and marketed oligonucleotide therapeutics addresses starting material designation, stereochemistry and impurity control strategy, identity testing strategy, terminal sterilization feasibility assessment, specification setting under ICH frameworks. We share platform efficiencies in manufacturing, method validation, stability consolidation, and container-closure integrity. We also outline regulatory review priorities—engagement and harmonized established conditions enable approvals and lifecycle management worldwide.

Substitution of a nonbridging oxygen for sulfur on the phosphodiester backbone of an oligonucleotide creates a chiral center at the phosphorus atom of the linkage. Oligonucleotides with >10phosphorothioate linkages are therefore mixtures of up to hundreds of thousands of diastereomers. It is essential to ensure manufacturing consistency and product quality by controlling factors that influence stereochemistry and by implementing proper analytical tools to analyze the stereochemical composition of phosphorothioated oligonucleotides. Here, we evaluated three orthogonal methods- CD, 31P NMR, and NP1 digestion followed by LC-MS- for their sensitivity to detect a change and their ability to monitor batch-to-batch stereochemical comparability. 

Chemically modified therapeutic oligonucleotides are less pure and contain many more complex impurities than typical molecules. Current chromatography methods struggle to resolve all the impurities. For this reason, either a mixture of UV and MS detection is used or alternatively a second orthogonal chromatography method. In this presentation we will discuss the current strategies for characterizing impurities and some ideas about how we can improve the toolbox in the future.

Ionis Pharmaceuticals has recently completed several large-scale manufacturing campaigns of conjugated small interfering RNA (siRNA) drug substances, including both peptide and GalNAc conjugates. These efforts have provided valuable insights into the unique challenges of siRNA manufacturing at commercial scale. This presentation will highlight observations related to process impurities encountered during synthesis and conjugation, and discuss strategies employed to optimize purification and isolation operations.

• Comparison with existing EMA guideline and established practices by key global regulators such as FDA, PMDA
• Considerations related to comparability and stereochemistry
• Increasing focus on bioassays to support characterization and CMC changes
• Potential impact to product lifecycle management
• Treatment of enzymatic ligation and starting material designation
  

• Outlining the roadmap of product development 
• Can the site support your Phase appropriate needs from per clinical onwards? 
• What are the onsite capabilities? Systems, equipment, scale up and analytical support
• Is the process transferable and are there any IP limitations to the process? 
• Level of support for analytical characterization/testing and CMC
  

The development of new therapeutics oligonucleotides can be quite different depending on purpose: N=1, rare disease, small or large indication, and other considerations. Presence of new modifications or usage of well-known starting materials can also impact the process. We will present some different situations to help attendees who are new to such endeavors. 

At Wave Life Sciences, the PRISM platform enables synthesis of stereopure oligonucleotides containing chimeric phosphorothioate (PS), phosphoryl guanidine (PN) and phosphodiester (PO) backbones that are rationally designed to optimize pharmacology and efficacy. We will describe approaches to synthesize and characterize stereopure oligonucleotides at multiple scales, which enables detailed structure-activity relationship analysis.

Sanegene Bio has built a strong hepatic siRNA pipeline and extended its LEAD (Ligand and Enhancer Assisted Delivery) platform across several extrahepatic programs. Extrahepatic delivery presents unique CMC challenges across process development, analytics, manufacturing, and scale-up. This presentation will share a case study on siRNA CMC development, highlighting practical strategies that enabled robust, scalable manufacturing to support IND-enabling activities for extrahepatic programs.

The manufacturing of Antibody-Oligonucleotide Conjugates (AOCs) has emerged as a critical area of innovation in the development of targeted therapeutics and diagnostic tools. These novel approaches aimed at improving the efficiency, specificity, and scalability of conjugation strategies, addressing key challenges such as site-selective modification, linker stability, and product homogeneity. By integrating advanced bioconjugation chemistries, optimized purification protocols, and automation-friendly workflows, these methods enable the production of high-quality conjugates suitable for both preclinical and clinical applications. The implementation of such innovative techniques enhances the functional performance of AOCs and also opens new possibilities for personalized medicine and next-generation drug delivery systems.

Oligonucleotide therapeutics continue to advance rapidly from concept to clinic, offering novel mechanisms to modulate gene expression and address previously intractable diseases. As these modalities mature, regulatory agencies worldwide are refining their expectations and issuing new guidance documents to address their unique CMC challenges. This presentation will explore emerging areas of convergence and divergence from the most recent regulatory developments, including draft and finalized documents from the FDA, EMA, CDE and other global health authorities. Key topics will include the evolution of CMC expectations and the increasing emphasis on platform-based development approaches.