Principal Scientist, Toxicology


Silverback Therapeutics, a Seattle-based biopharmaceutical company, is seeking a highly motivated individual to join our team and contribute to the discovery, preclinical and clinical development of innovative immune-modulating therapeutics.  This position is responsible for devising, implementing, and leading strategies to characterize the toxicologic properties of potential drug candidates, playing a critical role in advancing molecules through all stages of drug discovery and development.  The successful candidate will make key contributions to regulatory filings and in determining clinical dose levels for initial clinical trials, and will be comfortable working in a dynamic, fast-paced, and collaborative environment. This position is preferably based in Seattle, but flexible for the right candidate.


  • Serve as the Development Sciences/Toxicology Lead on multiple discovery and/or development teams, guiding characterization of safety properties of novel biologics to support decision-making and the advancement of preclinical programs and clinical drug candidates
  • Lead the design and conduct of exploratory, non-GLP, and GLP toxicology studies and the interpretation and reporting of results in the context of mechanisms of action or toxicity, dose- and exposure-response relationships, and the impact to predicted safety margins or therapeutic indices for putative drug candidates
  • Contribute to the design and conduct of related in vitro and in vivo studies (eg. pharmacology, pharmacokinetics) in collaboration with other team members, such as chemists, pharmacologists, bioanalytical scientists, and external contributors at contract research organizations
  • Independently formulate program toxicology strategy for and draft relevant sections of key documents supporting regulatory submissions (e.g. INDs)
  • Interpret, summarize and present data to internal project teams, senior management, and external partners/organizations


  • Ph.D. in toxicology or a related field and 10+ years of biotech/pharmaceutical drug discovery and development experience; Diplomate, American Board of Toxicology (or equivalent) preferred; title will be commensurate with experience
  • Regulatory experience supporting IND/CTA filings; experience in oncology drug development highly preferred and leading toxicology strategy for late-stage programs (e.g., pivotal trial design, NDA/MAA filings) a plus
  • Extensive experience and expertise devising toxicology strategy aligned with regulatory guidance and precedence, and in conducting toxicology studies for small molecule and biologics programs
  • Excellent critical thinking and scientific acumen, with a demonstrated ability to analyze, interpret, and clearly communicate (orally and in writing) complex toxicology study results and their impact to program and regulatory strategy

Silverback Therapeutics, Inc. is a privately held, clinical-stage biopharmaceutical company focused on leveraging its proprietary ImmunoTACTM technology platform to develop systemically delivered and tissue targeted therapeutics for the treatment of cancer and other serious diseases. Silverback’s platform enables the strategic pairing of proprietary payloads that modulate key disease modifying pathways with monoclonal antibodies directed at specific disease sites. Initially, Silverback is creating a new class of targeted immuno-oncology agents that direct a TLR8 agonist myeloid cell activator to the tumor microenvironment in solid tumors to promote cancer cell killing. Silverback’s lead product candidate, SBT6050, is a therapeutic comprised of a TLR8 agonist payload conjugated to a HER2-directed monoclonal antibody that targets tumors such as certain breast, gastric and non-small cell lung cancers. SBT6050 is currently in a Phase 1 clinical study in patients with advanced or metastatic HER2-expressing solid tumors ( Identifier: NCT04460456). Silverback Therapeutics is located in Seattle, Washington. To learn more, visit

We offer our employees competitive compensation and benefits, including paid time off, health insurance, life insurance, flexible spending accounts, a 401(k) plan, and stock options. Qualified candidates should forward their resumes to We are an equal opportunity employer.

© Copyright 2020 - Silverback Therapeutics™