Two very different plays in biotech fundraising landed on the same day: Soley Therapeutics closed a $200 million Series C to push its cell stress–sensing drug discovery platform into the clinic, and a Rakuten-backed photoimmunotherapy developer hauled in roughly $100 million as it eyes an FDA filing in 2028. Together they underscore a simple idea investors keep returning to—platforms that combine biology with heavy-duty tech can compress timelines and create new kinds of medicines.
Soley’s raise: scaling a cell-as-sensor approach
Soley, based in South San Francisco, pitched investors on something a little abstract and very ambitious: treat living human cells as time-resolved sensors of stress, then translate those signals into drug candidates. The company announced a $200 million Series C led by Surveyor Capital, with participation from HRTG Partners, RWN Management and a host of existing backers such as Doug Leone Family Fund and Breyer Capital. Soley Therapeutics says proceeds will fund IND-enabling work and early clinical trials for two internally discovered oncology assets—one headed toward an IND filing in 2026 for acute myeloid leukemia and another entering IND-enabling studies for solid tumors—as well as non-oncology programs for neurodegeneration and metabolic disease.
What makes Soley different is the stack: high-content, time-lapse imaging; proprietary computer vision to distill thousands of cellular features into compact signatures; automation that screens at scale; and AI/ML models that drive hit finding and molecule design. The company says it screens hundreds of thousands of compounds per week using in-house robotics and trains models with cloud and GPU partners to accelerate discovery. CEO Yerem Yeghiazarians framed the approach simply: measure how cells respond to stress, learn the signatures that predict beneficial outcomes, and then build drugs that replicate them.
Rakuten’s photoimmunotherapy push
On a parallel track, Rakuten’s life-sciences arm raised roughly $100 million to advance a photoimmunotherapy platform toward regulatory filings around 2028. Photoimmunotherapy—using light-activated agents to target tumors while sparing healthy tissue—has resurfaced recently as a promising niche where precision can translate into fewer side effects. The fresh capital will help finance late preclinical work and the regulatory path needed for an FDA submission in the latter half of the decade.
Different technical bets, similar investor appetite
These two financings highlight how investors are dividing their chips. Soley is a data- and AI-first phenotypic discovery engine that aims to produce many new chemical entities across indications. Rakuten’s play is more focused: a modality-driven therapeutic that pairs a biologic or conjugate with optical activation. One bets on breadth and platform throughput; the other bets on a modality’s clinical specificity and regulatory clarity.
Both stories also point to an important trend for biotech watchers: the rising expectation that sophisticated computing—be it computer vision, large-scale model training, or specialized cloud and GPU infrastructure—will materially change preclinical discovery. If that reads like the same playbook big tech uses, that’s because it is; biotech is borrowing both talent and tooling from AI research. For a sense of how image- and model-driven work is moving from labs into products, see how companies are building proprietary image models and new AI tools for research in adjacent tech spaces, from Microsoft’s MAI image efforts to changes in how large models search and ground enterprise data with Gemini-style integrations.
Why these rounds matter beyond the headlines
Large venture rounds do more than give companies runway. They validate a technical hypothesis in the marketplace: investors are saying these platform-first approaches are worth a major bet. That opens doors—talent, partnerships with big pharma, and access to specialized compute and automation suppliers—that can accelerate a program’s path to clinic. For patients, the practical consequence is that more diverse discovery strategies will be tested in human trials over the next several years.
Still, there are caveats. Platform-driven discovery faces translational risk—what a model or high-content signature predicts in cells may not always map cleanly to human biology. Modality-specific approaches like photoimmunotherapy must navigate manufacturing and delivery hurdles as well as regulatory scrutiny around novel device-drug combinations.
If both bets pay off, the industry could look different: a richer pipeline of medicines discovered by machines and microscopes, and more precise therapies that use light or other triggers to turn disease pathways on or off. For now, investors are buying the idea and giving these teams the fuel to test it in people.