We are seeking a Director or Senior Director of Discovery & Investigative Toxicology to provide scientific leadership in early safety assessment, in vitro screening, and mechanism-based toxicology for our bispecific/multispecific antibody discovery portfolio.

This role is intentionally focused on investigative toxicology and early risk mitigation, with particular emphasis on liabilities unique to bispecific/multispecific antibody modalities, including exaggerated pharmacology, target cross-linking, avidity-driven biology, tissue sink effects, and complex PK–tox relationships. The successful candidate will partner closely with Discovery Biology, Protein Engineering, and Pharmacology to design and apply in vitro and in vivo strategies that identify and mitigate safety risks early, before programs transition into formal development.

Experience with later-stage project toxicology and GLP toxicology assessments is considered a strong plus but is not required, and will be valued primarily for the ability to translate discovery-stage insights into development-ready strategies.

The ideal candidate is a biology-first toxicologist who combines deep mechanistic understanding with practical experimental judgment to de-risk complex antibody formats at the discovery stage.

Key Responsibilities

1) Investigative & Discovery Toxicology (Core Focus)

• Serve as the toxicology and safety biology lead for discovery-stage multispecific antibody programs.

• Identify and assess modality-specific safety risks, including:

• exaggerated or non-linear pharmacology

• receptor cross-linking and pathway overactivation

• on-target/off-tumor effects

• species-dependent target biology

• Design and oversee non-GLP, hypothesis-driven in vivo studies to interrogate safety mechanisms and inform candidate selection.

2) Early In Vitro Screening & Tox Mitigation

• Lead the design and deployment of early in vitro toxicology and safety screening strategies tailored to multispecific antibody formats.

• Define and apply fit-for-purpose in vitro assays to evaluate:

• target cross-reactivity and tissue binding

• exaggerated functional activity

• cytokine release and immune activation risk

• cell viability and pathway perturbation

• Partner with Protein Engineering and Discovery teams to use in vitro findings to guide molecule design, format selection, and lead optimization.

• Integrate in vitro and in vivo data to develop mechanism-based mitigation strategies and decision criteria.

3) PK-Informed Safety Interpretation (Discovery Stage)

• Collaborate with DMPK/PK scientists to interpret exposure-driven safety signals common to bispecific/multispecific antibodies.

• Assess the impact of target-mediated drug disposition, tissue sinks, and avidity effects on early safety findings.

• Support early human risk thinking without owning formal FIH dose justification.

4) Species Relevance & Translational Risk Assessment

• Apply deep understanding of species biology, target expression, and cross-reactivity to:

• select appropriate models

• interpret non-classical findings

• anticipate human relevance

• Translate early findings into clear, decision-enabling risk assessments for discovery and portfolio teams.

5) Portfolio & Program Decision Support

• Provide an independent safety perspective during candidate nomination and portfolio reviews.

• Clearly communicate uncertainty, confidence, and assumptions in early data.

• Support transition planning as programs move toward IND-enabling development.

6) Scientific Leadership & Discovery Culture

• Establish best practices for discovery toxicology and early safety screening in an outsourced biotech model.

• Mentor discovery-stage scientists and contribute to a culture of rigorous, mechanism-based decision making.

• Stay current on emerging approaches, including NAMs, where scientifically appropriate.

Qualifications

Required

• PhD, DVM, PharmD, or equivalent advanced degree in toxicology, pharmacology, pathology, or a related discipline.

• 10+ years of experience in discovery and investigative toxicology, preferably with biologics.

• Demonstrated expertise in mechanism-based safety assessment and early risk mitigation.

• Hands-on experience designing or applying in vitro toxicology or safety screening assays.

• Strong understanding of multispecific antibody biology and liabilities.

• Ability to operate effectively in data-limited, early discovery environments.

Preferred / Nice to Have

• Experience supporting later-stage project toxicology and/or GLP toxicology assessments for biologics.

• Familiarity with regulatory expectations for toxicology programs, particularly for antibodies.

• Veterinary training (DVM) and/or board certification (DACVP, DABT).

• Oncology and/or immunology program experience.