Supporting Innovation from Research to Clinical Manufacturing
In the rapidly evolving field of RNA therapeutics, precise and efficient delivery remains a critical challenge—especially for systemic administration. At Areterna, we are helping solve this challenge by providing reliable, scalable GalNAc conjugation solutions that enable targeted siRNA delivery to hepatocytes (liver cells).
We offer high-purity GalNAc amidites and CPGs, backed by extensive experience in chemical synthesis and oligonucleotide modification. From early discovery to IND-enabling studies and GMP-scale manufacturing, our team supports every stage of therapeutic development.
Why GalNAc? A Gold Standard for Liver-Targeted siRNA Delivery
GalNAc (N-Acetylgalactosamine) is a carbohydrate-based targeting ligand that has revolutionized liver-directed therapies. When conjugated to siRNA, it guides therapeutic payloads to asialoglycoprotein receptors (ASGPRs), which are highly expressed on the surface of hepatocytes.
Here’s why GalNAc has become the delivery vehicle of choice in the RNA world:
1. Hepatocyte-Specific Targeting
- ASGPR expression is largely confined to liver tissue, allowing precise targeting and minimizing uptake in non-hepatic cells.
- This specificity significantly reduces off-target effects, improving overall safety.
2. Efficient Cellular Uptake
- ASGPRs rapidly internalize GalNAc-conjugated oligos through clathrin-mediated endocytosis.
- The result: higher intracellular siRNA concentrations, improving silencing efficacy.
3. Improved Therapeutic Index
- Because siRNA is delivered directly to the liver, lower systemic doses are needed to achieve therapeutic effects.
- This reduces toxicity risk and increases patient tolerability.
4. Proven Clinical Success
Several FDA-approved RNA therapeutics already use GalNAc-based delivery:
- Givosiran (GIVLAARI®) for acute hepatic porphyria
- Lumasiran (OXLUMO®) for primary hyperoxaluria
- Inclisiran (LEQVIO®) for LDL-cholesterol lowering
These approvals underscore GalNAc’s effectiveness in enabling safe, potent, and targeted gene silencing.
GalNAc Architectures from Leading Biotech Innovators
The core concept of GalNAc-siRNA conjugation has evolved across companies into a variety of structures and platforms. Below is a summary of key innovations in the field:
1. Alnylam Pharmaceuticals
- Triantennary GalNAc scaffold with three ligands for strong ASGPR binding
- Used in: Givosiran, Lumasiran
- Benefits: Robust targeting and excellent in vivo stability
2. Ionis Pharmaceuticals (Roche/Novartis licensee)
- Tris-GalNAc with hydroxyprolinol linker
- Used in: Inclisiran (LEQVIO®)
- Benefits: Improved pharmacokinetics and stability under physiological conditions
3. Arrowhead Pharmaceuticals
- Dynamic Polyconjugate (DPC) Technology
- Includes GalNAc and a polymer component for enhanced endosomal escape
- Example: ARO-HBV (in clinical trials for chronic hepatitis B)
4. Dicerna (now Novo Nordisk) – GalXC™
- Tetra-antennary GalNAc: 4-ligand structure with asymmetric arms
- Used in: Nedosiran (Rivfloza™)
- Key Feature: Increased valency leads to stronger receptor engagement and improved potency
5. Silence Therapeutics
- Triantennary GalNAc with proprietary linkers
- Focus: Allele-specific gene silencing for cardiometabolic indications
- Example: SLN360 (for elevated lipoprotein(a))
6. Daiichi Sankyo – DS-9001 Series
- Branched GalNAc with cleavable linkers
- Benefit: Controlled endosomal release and enhanced intracellular delivery
7. Wave Life Sciences – GalNAc-STAND™
- Combines stereopure oligonucleotide chemistry with GalNAc targeting
- Application: WVE-006 (alpha-1 antitrypsin deficiency)
- Innovation: Precise control over backbone stereochemistry for improved efficacy
Trends in GalNAc Design and Optimization
Across the industry, researchers are fine-tuning GalNAc-siRNA conjugates to balance binding affinity, endosomal escape, and drug stability. Notable design variables include:
- Valency: 3 vs. 4 GalNAc ligands to optimize receptor interaction
- Linkers: Stable vs. cleavable for controlled release and tissue-specific kinetics
- Multifunctional Systems: Use of polymers or peptides to improve uptake and endosomal trafficking
At Areterna, we’ve successfully synthesized many of these structural variations and are well-equipped to support emerging innovations in conjugate design.
Our Capabilities
We offer:
- Custom GalNAc amidite synthesis (including branched, triantennary, and tetra-antennary types)
- Functionalized CPGs for solid-phase oligo synthesis
- Batch sizes ranging from milligrams to kilograms
- Analytical support and structure validation
- Rapid turnaround times to accelerate your development timeline
Our team collaborates closely with clients to meet both technical specifications and regulatory standards—whether you’re optimizing lead candidates or scaling for clinical trials.
Ready to Advance Your siRNA Program?
Whether you need standard triantennary GalNAc structures, novel conjugation strategies, or a reliable partner for scale-up, Areterna is here to help.
With deep technical know-how and flexible production capabilities, we are proud to be a trusted supplier in the RNA therapeutics ecosystem.
? Contact us today to learn more about our GalNAc solutions and how we can accelerate your path from research to clinic.