Antibody–Drug Conjugates

Sai Life Sciences delivers integrated discovery, development, and manufacturing solutions for complex antibody–drug conjugate (ADC) and emerging bioconjugate modalities. Our capabilities span the complete value chain – from payload and linker synthesis (including large-scale manufacturing) to conjugation, purification, analytical characterization, and biology evaluation at discovery and R&D scale.

We have successfully executed multiple programs across diverse ADC warhead classes, including R&D-scale bioconjugation, supporting innovators from early development through commercial supply of payloads and linkers.

Chemistry of Linker–Payloads

We offer comprehensive expertise in payload and linker chemistry, serving as the foundation for ADC development:

• Synthesis and scale‑up of cytotoxic payloads
• Development of linkers and fully assembled payload–linker constructs
• Experience with diverse warhead classes and novel chemistries End‑to‑end integration from payload–linker to conjugate synthesis
• Fully integrated analytical and purification workflows
• Dedicated isolator facilities with containment of 0.01 µg/m³ (OEB 6)

ADC Bioconjugation

Our advanced ADC bioconjugation capabilities support a wide range of conjugation strategies:

• Lysine-based (random labeling)
• Cysteine-based (reduced/interchain disulfide)
• Site-specific approaches (engineered cysteine, enzymatic, tag-based)
• Next-generation formats: dual-payload ADCs, degrader antibody conjugates (DACs), multivalent/modular conjugates
• Advanced formats including antibody–oligonucleotide conjugates (AOC)

Facility Highlights 

• Cytiva ÄKTA systems for purification
• Dedicated bioconjugation suites with isolated AHU for controlled environments

Our teams enable rapid development and optimization of conjugation strategies, tailored to target biology and payload chemistry.

ADC & Bioconjugate Purification and Scale

• R&D‑scale purification of ADCs and bioconjugates (scalable to gram-scale quantities in batches)
• Chromatography workflows for DAR control, impurity removal, and aggregate clearance
• Efficient removal of free payloads and unconjugated species
• Cytiva ÄKTA systems for precise, scalable downstream processing
• Operations in controlled environments with dedicated AHU systems for integrity and containment

ADC & Bioconjugate Analytical Characterization

Our integrated analytics platform supports comprehensive characterization of ADCs:

• Intact mass analysis by HRMS
• DAR determination and distribution profiling
• Free linker–payload analysis
• Purity and aggregation assessment
• In vitro stability in plasma/biological matrices and PK analysis

This enables robust structure–function understanding and supports seamless progression from discovery to development.

ADC Biology and Functional Characterization

We support early‑stage biological evaluation of ADCs to enable rapid decision‑making and candidate selection:

• In vitro cytotoxicity assays
• Internalization studies
• Lysosomal degradation studies
• Bystander effect assessment

In Vivo Evaluation
Our in vivo capabilities include:

• PK/PD profiling, including exposure–response and DAR assessment
• Tolerability and dose-range finding studies
• Efficacy in xenograft and relevant tumor models
• Biodistribution analysis using LC‑MS

These studies delivers key insights on exposure, target engagement, and anti-tumor activity to enable data-driven decisions and strong translation to in vivo efficacy.

Beyond oncology, we also support and are exploring applications in metabolic and inflammatory diseases, leveraging ADC platforms for targeted modulation of disease biology.