Hexagon Bio Raises $62M Series C for Novel ADC Payloads

A molecule found through a microbial genome has a long way to travel before it belongs in a patient's treatment plan. Hexagon Bio is financing the next stretch of that journey, putting its discovery work behind a specific cancer drug candidate and a planned move into human testing.

The Menlo Park, California company announced a $62M Series C on October 23, 2026, led by The Column Group, with existing investors Nextech Invest, Deviation Capital, 8VC and Canada Pension Plan Investment Board participating. Proceeds will support HEX-360, a HER2-targeting antibody-drug conjugate, or ADC, and further payload research. Hexagon anticipates starting a Phase 1 study in the first half of 2027, connecting its ambition to address resistance to existing ADC payloads with a concrete clinical-development plan.

Why Hexagon is changing the payload

An ADC combines an antibody with a drug molecule attached through a chemical linker. The National Cancer Institute's definition describes how the antibody recognizes particular proteins or receptors on cells and carries the linked drug to them. That architecture gives developers several places to work: the target, the antibody, the linker and the payload itself.

Hexagon is concentrating on what the delivered molecule does. HEX-360 uses a protein translation inhibitor, designed to interfere with production of proteins cancer cells need. The company's technology platform is pursuing mechanisms different from the topoisomerase and tubulin inhibition approaches familiar in the ADC field. Its development rationale is that a different cellular attack could remain useful when a tumor has become resistant to an earlier payload class.

For a drug developer, treatment sequence therefore becomes part of the product question. Finding a target on a cancer cell is one task; choosing a payload that remains useful after earlier treatment adds another. Hexagon's approach makes that relationship central to its research program, with human evidence still ahead. The funding gives the team resources to investigate a specific candidate while continuing the search for other mechanisms that could supply its future pipeline.

A discovery platform takes on a clinical timetable

Hexagon's current pipeline identifies HEX-360 as its lead HER2 program and shows additional ADC and dual-payload work with undisclosed targets. The lead candidate remains in IND-enabling studies. The anticipated first-half 2027 trial is a company projection, giving the financing a development destination without turning the timetable into a completed milestone.

The underlying discovery work starts much earlier. Hexagon combines microbial genomic information, computational prediction and laboratory work to identify molecules with biological effects. Synthetic biology, chemistry and production capabilities help the company turn those findings into candidates it can investigate. Owning more of that chain allows a clinical question about resistance to influence the chemistry being developed further upstream.

The distinction between a candidate and a platform matters to the capital allocation. HEX-360 gives the company a defined program around which to organize clinical work. Continued payload discovery keeps the business from depending intellectually on a single molecule or one cancer-cell target. The announced use of proceeds includes both responsibilities, although the release does not disclose their separate budgets, an estimated cash runway or the financial requirements of later trials.

That leaves investors and potential development partners following two connected forms of progress. One concerns a particular investigational medicine moving toward human testing. The other concerns whether the discovery operation can keep supplying scientifically useful options as the questions become more demanding.

The people and capital behind the transition

CEO and co-founder Maureen Hillenmeyer previously directed a natural-products discovery program at Stanford, according to Hexagon's current leadership biographies. Co-founder Colin Harvey remains VP of Synthetic Biology. The company also identifies Yi Tang and Brian Naughton as co-founders, with Naughton's former CTO role explicitly described as historical.

The current team includes CSO Tara Arvedson, CMO Bill Grossman and Victor Cee, SVP of Drug Discovery. That combination places discovery and clinical expertise inside the same organization as HEX-360 approaches its planned first study. Their roles make the financing's operating consequence legible: the company must keep producing candidates while developing the capabilities to study a lead program in people.

The financing history also shows continuity. Hexagon disclosed a $47M Series A in 2020 and a $61M financing in September 2021. A $77.3M Series B followed in February 2023. These are individual historical announcements; the latest release supplies neither a reconciled lifetime funding figure nor a valuation.

The Column Group participated in earlier financings and now leads the Series C. Its own investment model emphasizes supporting scientific platforms across development stages. Here, that continuity accompanies the movement from discovering potential payloads to preparing a named ADC for the clinic, while the company's research remit continues beyond HEX-360.

What the preclinical evidence can establish

Hexagon presented research on its HER2 translation-inhibitor ADC at AACR's 2026 annual meeting. The company's scientific poster describes experimental antitumor activity, including resistant models, and animal tolerability findings. Those observations support the rationale for further development within the limits of the experiments reported.

Clinical development will bring different questions into view. A study in people must investigate how a candidate behaves at clinically relevant exposures, what dose can be used and which unwanted effects appear. The FDA's ADC clinical-pharmacology guidance addresses dosing, exposure-response relationships and other considerations that arise from combining several constituent parts in one therapy. A favorable laboratory result cannot supply those patient observations in advance.

The financing is consequential because it gives Hexagon a route toward generating that next kind of evidence. The company's intended place in oncology is tied to a patient history: cancer that has progressed despite exposure to existing ADC mechanisms. Whether HEX-360 can serve that situation will depend on the clinical work the team is now preparing, alongside its continuing search for molecules capable of changing what the next payload can do.