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

SystImmune 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). SystImmune has multiple assets in various stages of clinical trials for solid tumor and hematologic indications, alongside a robust preclinical pipeline of potential cancer therapeutics in the discovery and IND-enabling stages.

About the Role

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.

Responsibilities

• 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.
• 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.

Qualifications

• 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.

Skills

• 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.

Preferred Qualifications

• 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.

Why Join Us

• 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 environment bridging pathology, translational science, and regulatory strategy.

Pay

The expected base salary range for this position is $90,000 - $140,000 annually. Actual compensation will be based on a variety of factors, including but not limited to a candidate’s qualifications, level of the position, experience, and skills.

Benefits

• 100% paid employee premiums for medical, dental, and vision insurance.
• Short-term and long-term disability coverage.
• 401(k) plan with a 50% company match of up to 3% and a vesting schedule of 5 years.
• 15 PTO days per year, sick leave, plus 11 paid holidays.