Location: San Francisco, CA
Compensation: $150-250,000 + equity and comprehensive benefits package
Lead the In Vivo Studies That Decide Which Therapies Move Forward
Helix BioSearch is partnering with an ambitious, early-stage biotechnology company in San Francisco developing new therapeutic candidates. Founded by a mission-driven team with backgrounds spanning leading academic institutions, top-tier research hospitals and global pharma, the company combines speed with scientific rigor to move its most promising candidates forward quickly and decisively.
The Opportunity
We are seeking an experienced Senior or Principal Scientist in In Vivo Pharmacology to lead the design, execution and interpretation of mouse studies that determine whether therapeutic candidates reach the right tissue, engage the target, improve the phenotype and remain tolerable. This is a highly visible opportunity for a hands-on scientist who brings clarity to open-ended problems, takes ownership of next steps and wants their judgment to shape candidate decisions directly.
Working closely with the molecular, histology and biomarker teams, you will stay hands-on with in-life work while using pharmacokinetic/pharmacodynamic (PK/PD), efficacy and safety data to make clear next-study and candidate decisions, with close feedback from the people making the company’s key scientific calls.
Key Responsibilities
Design, run and interpret mouse studies evaluating therapeutic candidates across efficacy, pharmacology and safety.
Define the dose, route, schedule, tissues, timepoints, endpoints, controls and go/no-go criteria for each study.
Perform and guide dosing by routes including intraperitoneal (IP), intravenous (IV), subcutaneous (SC), oral (PO) and intranasal, selecting methods based on mechanism and exposure goals.
Perform or oversee in-life work, including blood collection, necropsy, tissue collection, surgeries and specialized procedures.
Maintain robust sample tracking from in-life collection through to downstream analysis.
Analyze PK/PD, efficacy, tolerability, biomarker and tissue data to determine the next dose, route, schedule, timepoint or candidate to test.
Design and execute electroencephalography (EEG) studies where required, including surgery, electrode placement, monitoring and electrophysiological data processing.
Partner with downstream molecular, histology and biomarker workflows to ensure studies generate high-quality, decision-ready data.
Turn each dataset into the next well-controlled experiment, driving a fast and disciplined path to candidate decisions.
What We're Looking For
Substantial hands-on experience designing and running mouse studies in biotech, pharma, academia or a closely related setting.
Strong translational judgment, with the ability to design studies that test tissue exposure, target engagement, pathway modulation, phenotype and tolerability.
Comfort with multi-route dosing, in-life execution, necropsy, tissue and blood collection, sample tracking and coordination with downstream assays.
Demonstrated ability to interpret PK/PD and efficacy data and make disciplined next-study or candidate decisions.
A fast, rigorous working style built on explicit hypotheses, dose rationale, endpoints, controls and go/no-go criteria.
The drive to take ownership of open-ended problems and follow through with energy in an early-stage environment.
Experience with EEG studies is valuable, though you do not need prior experience with every route, procedure or assay listed above.
Why Apply?
Base Salary: $150,000 – 250,000
Generous equity options
Medical, dental and vision coverage
Access to HSA, FSA and 401(k) plans
This is an opportunity to join a small, high-integrity team at an early and formative stage, surrounded by people who care intensely about the work. You’ll play a pivotal role in deciding which therapeutic candidates advance, with your in vivo data directly shaping the company’s scientific direction.
If you’re passionate about in vivo pharmacology, translational study design and turning rigorous data into clear decisions, we’d love to hear from you.