Head of Protein Sciences

Head of Protein Sciences

Location: San Francisco, CA (on-site position)

Company: Stealth-mode biotechnology venture

Role Overview

A stealth-mode biotechnology company in San Francisco is seeking a seasoned Head of Protein Sciences to lead discovery, optimization, and early development of protein-based targeting agents for a next-generation radioligand therapy (RLT) platform. This role spans discovery through early CMC, with accountability for engineering and advancing engineered protein therapeutics optimized for targeted radiotherapeutic delivery.

The ideal candidate brings deep expertise in protein engineering, analytics, and expression, with a proven track record of advancing biologics into the clinic—and preferably through late-stage development and approval. This is a highly cross-functional leadership role requiring close integration with radiochemistry, pharmacology and translational sciences, CMC, and clinical development.

Key Responsibilities:

Scientific & Portfolio Leadership

• Define and execute the protein sciences strategy aligned with the company’s RLT platform and pipeline
• Serve as the scientific owner for protein-based programs from target selection through clinical candidate nomination
• Contribute to portfolio prioritization, platform evolution, and long-term pipeline planning

Protein Discovery & Engineering

• Lead discovery, engineering, and optimization of protein therapeutics with properties tailored for radioligand applications (affinity, specificity, internalization, PK/PD, stability)
• Oversee antibody and protein discovery approaches including display technologies, immunization strategies, in silico design, and affinity maturation
• Apply structure-based and data-driven methods to improve developability and manufacturability

Protein Analytics & Characterization

• Establish and oversee protein analytics and characterization strategies, including biophysical, biochemical, and functional assays
• Ensure robust evaluation of purity, stability, aggregation, binding kinetics, epitope, and structure–function relationships
• Integrate analytical data into discovery and candidate selection decisions

Expression Platforms & Early CMC

• Provide leadership across multiple potential protein expression systems, including mammalian, yeast, prokaryotic, and in vitro expression platforms
• May oversee cell line development (CLD), expression optimization, and early process development to enable scalable manufacturing
• Partner with CMC to ensure seamless transition from discovery to IND-enabling activities

Radioligand-Specific Optimization

• Guide protein design for radiolabeling compatibility, including site-specific conjugation and chelator strategies
• Collaborate with radiochemistry and translational teams to optimize tumor uptake, biodistribution, clearance, and dosimetry
• Incorporate in vivo data to iteratively refine protein formats and constructs

CRO & External Partner Management

• Manage and coordinate CROs and external partners across discovery, analytics, expression, and early CMC activities
• Establish clear scopes, timelines, and success criteria to ensure high-quality, on-time execution
• Build productive academic and industry collaborations to extend internal capabilities

Team Leadership & Development

• Build, mentor, and lead a high-performing Protein Sciences organization
• Foster a culture of scientific rigor, accountability, and cross-functional collaboration
• Establish best practices, workflows, and decision frameworks appropriate for a growing biotech

Cross-Functional & Executive Engagement

• Work closely with radiochemistry, pharmacology, translational, CMC, regulatory, and clinical teams
• Support regulatory interactions, IND filings, and technical documentation
• May serve as a senior scientific representative in partnering, investor, and board discussions

Qualifications:

Required

• PhD or equivalent in Protein Engineering, Biochemistry, Structural Biology, Immunology, Oncology or related discipline
• At least 15 years of industry experience in biologics discovery and development
• Deep hands-on expertise in protein therapeutics discovery and engineering, including protein conjugate therapeutics, preferably radioligand therapeutics or other protein-drug conjugates. Direct experience with Nb, VHH, sdAb in addition to mAb-based therapeutics strongly preferred.
• Demonstrated experience in protein analytics, expression, and early CMC activities including cell line development
• Proven success advancing multiple biologic programs into the clinic
• Experience managing CROs across discovery, analytics, and CMC

Strongly Preferred

• Track record of advancing biologics through late-stage development, BLA submission, and/or regulatory approval
• Experience with radioligand therapies, ADCs, or targeted delivery platforms
• Familiarity with regulatory expectations for biologics CMC and comparability
• Experience building and scaling teams in a startup or high-growth biotech environment

Leadership Attributes

• Strategic thinker with strong scientific judgment and execution focus
• Comfortable operating in ambiguous, resource-constrained environments
• Collaborative, decisive, and hands-on leader
• Credible scientific voice with internal and external stakeholders

Leveling & Compensation

• Title and scope commensurate with experience
• Competitive compensation package including equity participation

Why Join Us

• Opportunity to shape the protein discovery and engineering engine of a cutting-edge radioligand therapy company.
• Significant influence over scientific strategy, pipeline direction, and company growth.
• Competitive compensation and equity aligned with a leadership role.