Hexagon Bio, a Menlo Park, California, biotech company that develops antibody-drug conjugates (ADCs) for cancer, has closed a $62m Series C financing. The company announced the round on 23 October 2026.
The Column Group led the round. Existing investors Nextech Invest, Deviation Capital, 8VC and Canada Pension Plan Investment Board (CPP Investments) also took part. Hexagon Bio did not disclose a valuation or how much it has raised in total.
“This financing reflects our conviction that the next generation of ADCs will be focused on novel payloads that can transform the treatment paradigm for many cancers.”Maureen Hillenmeyer, Co-founder and CEO, Hexagon Bio
What Hexagon Bio does
An antibody-drug conjugate links an antibody, which seeks out a marker on cancer cells, to a toxic drug known as the payload. Hexagon Bio focuses on the payload. The company uses what it calls a natural products platform: it searches microbial genomes for small molecules that kill cells and could be attached to antibodies.
According to the company, advances in DNA sequencing have let it find both the kinds of payloads already used in approved ADCs, such as topoisomerase and tubulin inhibitors, and molecules that attack other pathways that cancer cells depend on, such as the production of proteins.
Hexagon Bio argues that this matters because tumours often become resistant to the small set of payloads used in current ADCs, and those payloads can be hard for patients to tolerate. Drugs that kill cells in a different way could, in its view, be used after existing treatments stop working. The company says its pipeline is aimed at a range of solid tumours and blood cancers.
The lead drug, HEX-360
The company's lead candidate is HEX-360, an ADC that targets HER2, a protein found on the surface of some breast and other cancer cells. Its payload is a translation inhibitor that Hexagon Bio discovered. Rather than damaging DNA or the cell skeleton, it is designed to stop cancer cells from producing the proteins that drive their growth.
At the American Association for Cancer Research annual meeting in 2026, the company presented preclinical results for HEX-360. In mouse models built from cancer cell lines and from patient tumours, the drug performed as well as or better than a comparator modelled on ENHERTU, an approved HER2 ADC, when both delivered the same amount of payload. The company said HEX-360 also produced deep and lasting responses in models that resist topoisomerase inhibitors and was well tolerated in rats and non-human primates. These are animal studies; the drug has not yet been tested in people.
HEX-360 is in IND-enabling studies, the safety and manufacturing work required before US regulators allow a first human trial. Hexagon Bio recently set up a clinical advisory board of breast cancer specialists to help guide its development.
What the money is for
Hexagon Bio said the proceeds will fund a Phase 1 trial of HEX-360, which it expects to begin in the first half of 2027. The money will also go to further payload mechanisms from its platform and to dual-payload ADCs, which carry two different drugs on one antibody.
Chief executive and co-founder Maureen Hillenmeyer said the capital would let the company quickly become a clinical-stage business and move closer to offering options to patients whose cancer has progressed on current ADCs or who cannot tolerate them.
Scott Garland, chairman of the company's board, said the industry needs to look beyond existing payloads, and pointed to the company's progress in moving HEX-360 towards the clinic while finding new payload mechanisms at the same time.
A crowded field
ADCs have become one of the most active areas of cancer drug development, and HER2 is among the most heavily pursued targets. Hexagon Bio is betting that a different payload, rather than a different antibody, is what will set its drug apart. Whether HEX-360's animal results carry over to patients will only become clear once human trials begin.
Company website: hexagonbio.com