One receptor. Three cancers. A lean Redwood City biotech turning a single clinically-validated CSF1R antibody into a first-in-class oncology pipeline.
AmMax Bio, Inc. is a clinical-stage biotechnology company in Redwood City, California, developing first-in-class therapeutics for cancer patients from a single scientific idea: that the receptor CSF1R is a lever worth pulling across multiple tumors.
The company was founded in 2020 by Larry Hsu, PhD, in partnership with Amgen. Under that founding arrangement, AmMax licensed exclusive worldwide rights to a monoclonal antibody targeting the colony-stimulating factor 1 receptor - CSF1R - and Amgen took a minority stake. That one asset became the seed of everything the company has built since.
CSF1R sits at the center of the tumor microenvironment, the ecosystem of immune cells and signals that surrounds a tumor. Tumor-associated macrophages depend on it. By engaging CSF1R, AmMax's programs are designed to act on the neighborhood a cancer lives in, not only the cancer cell itself - and, in the case of its antibody-drug conjugate work, to deliver a cytotoxic payload directly to cells that carry the receptor.
What makes AmMax distinctive is less a single molecule than a method. The company deliberately leverages clinically validated components - an antibody already tested in roughly 200 patients and healthy subjects across five earlier trials, plus established linker-payload technology - to reduce development risk while improving the odds on efficacy and safety. In an industry where most failures come from biological surprises, that reuse is the strategy.
The result is a company that looks small on paper - about a dozen employees - but runs a pipeline spanning three distinct cancers: tenosynovial giant cell tumor, colorectal cancer minimal residual disease, and acute myeloid leukemia.
The platform logic is straightforward: take one validated antibody, combine it with proven enabling technologies, and point it at multiple indications where CSF1R biology matters.
Diagram is an illustration of AmMax's stated development approach, not an official corporate schematic.
AmMax's pipeline is organized around what CSF1R can do in different disease settings - from a solid-tumor antibody to a blood-cancer antibody-drug conjugate.
An antibody-drug conjugate pairing AmMax's CSF1R antibody with Lonza's exatecan-based SYNtecan payload. Designed to directly kill monocytic AML cells and address venetoclax/azacitidine resistance. IND planned for early 2027.
A potent CSF1R monoclonal antibody aimed at minimal residual disease - the cells left behind after standard treatment. Co-developed with MD Anderson; first patient dosed in a Phase 2a study in early 2025.
A potent monoclonal antibody against CSF1R for TGCT, granted FDA Fast Track designation and EMA PRIME designation.
A CSF1R-targeting antibody program in the TGCT setting, extending AmMax's work in this rare tumor of the joints and tendons.
Two hard problems sit at the heart of AmMax's work. The first is relapse. In acute myeloid leukemia, some patients recur because standard regimens leave resistant monocytic leukemia cells behind. AMB-104 is engineered to find those cells through CSF1R and deliver a cytotoxic payload straight to them.
The second is minimal residual disease. After surgery or chemotherapy for colorectal cancer, trace disease can persist below the threshold of routine imaging - detectable by ctDNA biomarkers but historically difficult to treat. AmMax and MD Anderson are testing whether AMB-066 can act on that residual disease before it becomes a recurrence.
How is AmMax different from the field? Many oncology companies chase brand-new molecules against brand-new targets, accepting high biological risk for the chance of a breakthrough. AmMax takes the opposite posture. It reuses an antibody with substantial human safety data and licenses established payload chemistry, betting that disciplined recombination beats speculative novelty.
That places it among tumor-microenvironment and antibody-drug-conjugate developers - alongside larger ADC players and TGCT-focused competitors - but with a capital-efficient, partnership-driven model that a 12-person team can actually execute.
AmMax is led by Larry Hsu, PhD - founder and CEO - who previously co-founded and led Impax Laboratories, building it into a multi-billion-dollar publicly traded pharmaceutical company. He is joined by an experienced executive team including President & COO Travis Read, CFO Andrew Sauter, CSO Kirk Johnson, PhD, and CBO Laura Zhu, PhD.
Founding partner. AmMax licensed exclusive worldwide rights to a CSF1R monoclonal antibody, and Amgen holds a minority ownership stake.
Co-development agreements to advance AMB-066 in colorectal cancer patients with minimal residual disease.
Non-exclusive license (June 2026) to the exatecan-based SYNtecan linker-payload platform powering the AMB-104 ADC program.
On the business side, AmMax is a privately held clinical-stage company. Its Series A round drew investors including Forward Asset Management and Taiwania Capital, with Amgen participating through its founding stake. Its model creates value by advancing de-risked candidates through the clinic toward partnership, licensing, or approval.
AmMax's expertise is concentrated where antibody engineering meets the tumor microenvironment. Its scientific team works on CSF1R biology - confirming, for its AML program, that the receptor is overexpressed on patient samples, that the antibody is efficiently internalized into leukemia cells, and that the resulting conjugate shows activity in preclinical models. That is the kind of translational, indication-by-indication work that turns a target into a drug.
The company also carries deep operating experience. A founder who built a multi-billion-dollar pharmaceutical company, combined with a team drawn from established biotech and clinical development, gives AmMax the practical know-how to run trials, negotiate licenses, and manage the regulatory path - the parts of biotech that rarely make headlines but decide outcomes.
On the market map, AmMax sits at the intersection of two fast-moving fields. Antibody-drug conjugates have become one of oncology's most active areas, dominated by large players investing heavily in linker-payload chemistry. Separately, minimal residual disease - long a diagnostic concept measured by ctDNA - is emerging as a therapeutic target that established companies are only beginning to pursue. AmMax is trying to be early in both, from a rare-tumor foothold in TGCT to blood and solid tumors.
Its competitors are therefore varied: ADC leaders such as Daiichi Sankyo and AstraZeneca, TGCT-focused developers, and larger groups exploring the residual-disease space. AmMax's answer to that scale is focus and capital efficiency - a narrow target, borrowed technology, and a team small enough to move quickly.
Larry Hsu, PhD launches the company in partnership with Amgen, licensing worldwide rights to a CSF1R monoclonal antibody.
The CSF1R antibody earns FDA Fast Track and EMA PRIME designations in TGCT; Series A funding closes.
AmMax and MD Anderson announce agreements to co-develop AMB-066 for colorectal cancer MRD; the company presents at the Oppenheimer Healthcare Showcase.
First patient dosed in a Phase 2a study of AMB-066 in colorectal cancer minimal residual disease.
AmMax licenses Lonza's SYNtecan platform for its lead AML ADC and names Travis Read President & COO. IND planned for early 2027.
It is a clinical-stage biotech in Redwood City, California developing first-in-class cancer therapeutics from a CSF1R-targeting antibody platform, with programs in AML, colorectal cancer minimal residual disease, and TGCT.
It was founded in 2020 by Larry Hsu, PhD, in partnership with Amgen. Hsu previously co-founded and led Impax Laboratories.
AMB-104 is AmMax's lead program: an antibody-drug conjugate combining its CSF1R monoclonal antibody with Lonza's exatecan-based SYNtecan payload to treat acute myeloid leukemia, with an IND planned for early 2027.
Amgen (founding partner and minority owner), MD Anderson Cancer Center (colorectal MRD co-development), and Lonza (SYNtecan linker-payload license).
No. As of 2026 it is a privately held clinical-stage company backed by investors including Forward Asset Management, Taiwania Capital, and Amgen.
Video link is a YouTube search - AmMax Bio does not appear to maintain an official interview or product-demo channel as of this writing. All facts above are drawn from public sources and company press releases.