Evolving functional therapeutics inside living cells for challenging intracellular targets

Most drug discovery happens outside the cell and only later tests function. Bullseye discovers molecules directly in living cells, linking molecular activity to function from the start.

Starting with function, not proxies.

The most important biology remains hard to drug

Many high-value disease targets act through intracellular protein–protein interactions and transcriptional regulation. These targets are central to cancer and other serious diseases, yet remain difficult to address with conventional discovery approaches.

Traditional methods struggle because these systems depend on complex cellular context that is not captured in simplified assays.

Drug discovery often starts too far from biology

Most discovery approaches screen molecules outside the cell and only later test whether they work in biological systems. This creates a fundamental gap between early discovery and therapeutic reality.

Molecules that perform well in vitro frequently fail in the cellular environment where disease actually occurs.

We discover molecules where biology actually happens

Bullseye uses directed evolution inside living cells to discover functional molecules against challenging intracellular targets.

Rather than starting with a predefined mechanism or simplified assay, we generate and evaluate molecular diversity directly in cells, selecting for the biological outcome that matters.

Build intracellular selection systems
Engineered cellular circuits link target activity to measurable outputs

Evolve molecules in cells
Diverse libraries are continuously generated and tested directly in living systems

Select for function
Only molecules that produce the desired cellular effect are enriched

Multiple mechanisms. One discovery approach.

Because we select for function inside living cells, we are not limited to a single mechanism of action.

Our platform can discover molecules that:

  • Induce protein interactions (molecular glues)

  • Disrupt pathogenic interactions

  • Rewire or stabilize multi-protein complexes

Traditional discovery targets predefined mechanisms.
Bullseye discovers what works in the cell.

Modality follows function

Bullseye is not constrained to a single therapeutic modality.

Our platform enables discovery across:

  • Macrocyclic peptides

  • Stapled peptides

  • Other intracellularly active scaffolds

Rather than forcing biology to fit a predefined approach, we identify the molecular solution that works.