Scientist​/Senior Scientist, Companion Diagnostics (CDx) – IHC Development

Scientist Or Senior Scientist

Syst Immune is a leading and well-funded clinical-stage biopharmaceutical company located in Redmond, WA and Princeton, NJ. It specializes in developing innovative cancer treatments using its established drug development platforms, focusing on bi-specific, multi-specific antibodies, and antibody-drug conjugates (ADCs). Syst Immune has multiple assets in various stages of clinical trials for solid tumor and hematologic indications. Alongside ongoing clinical trials, Syst Immune has a robust preclinical pipeline of potential cancer therapeutics in the discover and IND-enabling stages, representing cutting-edge biologics development.

We offer an opportunity for you to learn and grow while making significant contributions to the company's success. We are seeking a Scientist or Senior Scientist to lead and support immunohistochemistry (IHC) assay development for companion diagnostic (CDx) kits supporting oncology drug development. This role is responsible for end-to-end IHC assay development, including antibody selection, assay optimization, analytical validation, and clinical trial implementation, with a clear development path from RUO/LDT to IVD CDx commercialization.

The ideal candidate has strong expertise in pathology, IHC assay development, and CDx regulatory expectations, and can work effectively across R&D, clinical, regulatory, QA, and external CROs and central laboratories.

• Lead development of IHC-based CDx assays, from biomarker discovery through assay optimization and validation.
• Select and evaluate primary antibodies, detection systems, and staining platforms (e.g., Ventana, Dako, Leica).
• Optimize assay parameters, including epitope retrieval, antibody dilution, detection chemistry, and staining conditions.
• Establish scoring algorithms, cut-off strategies, and interpretation guidelines in collaboration with pathologists.
• Support biomarker strategies for patient selection and stratification in clinical trials.

• Design and oversee analytical performance studies, including:
  • Sensitivity and specificity
  • Precision and reproducibility (intra-run, inter-run, inter-site)
  • Accuracy and robustness
  • Linearity and limit of detection, where applicable
• Prepare, review, and approve validation protocols, reports, and SOPs in alignment with CDx expectations.

• Support implementation of IHC assays in clinical trials, including:
  • Central laboratory qualification and oversight
  • Pathologist training and alignment
  • Slide logistics, staining consistency, and scoring harmonization
• Collaborate with clinical teams on sample strategy, feasibility studies, and biomarker cut-off justification.
• Regulatory & Quality Collaboration
• Work closely with Regulatory Affairs and Quality Assurance to ensure compliance with:
  • FDA CDx guidance (US)
  • NMPA/CDE requirements (China), where applicable
  • IVDR (EU), as relevant
• Support preparation of regulatory documentation, including:
  • IDE/IND biomarker sections
  • CDx bridging strategies (RUO/LDT → IVD)
  • Analytical and clinical performance summaries
• Ensure assay development aligns with QMS requirements, design controls, and document traceability.

• Serve as a technical subject-matter expert, interacting with:
  • CROs, central laboratories, and IVD partners
  • Antibody vendors and staining platform providers
• Provide scientific input to project teams, governance meetings, and external collaborations.
• Mentor junior scientists and contribute to team capability building, as appropriate.

• PhD in Pathology, Molecular Biology, Immunology, Oncology, or a related field
• MS or BS with significant CDx or IVD industry experience may be considered

• 3–5+ years of hands-on experience in IHC assay development, preferably in a CDx or IVD setting
• Direct experience supporting oncology biomarkers and clinical trials
• Experience across the CDx development lifecycle (RUO/LDT through IVD readiness)
• Strong understanding of IHC scoring methodologies (e.g., TPS, H-score, CPS)
• Familiarity with analytical validation and regulatory expectations for CDx
• Demonstrated ability to work effectively in cross-functional teams

• Strong scientific rigor with excellent documentation and data interpretation skills
• Ability to operate in a fast-paced, matrix environment
• Clear and effective communication with both technical and non-technical stakeholders
• Experience working with global teams is a plus

• Prior experience with late-stage or FDA-approved CDx programs
• Experience developing and justifying biomarker cut-off strategies
• Familiarity with NSCLC, GI cancers, or other solid tumors
• Experience interacting with health authorities or supporting regulatory meetings

• Opportunity to shape next-generation CDx programs linked to innovative oncology therapeutics
• High-visibility role with direct impact on patient selection and drug approval
• Collaborative…