The awkward thing about a promising cancer molecule is that it has usually impressed the easiest audience first: a laboratory. Cells respond. Animal models oblige. Then comes a person, whose disease has a history, whose body imposes limits, and whose cancer has already learned to survive treatment. OnCusp Therapeutics has chosen to build a business at this crossing. Its job is to take research assets far enough into clinical testing that a pharmaceutical partner has something more substantial than an elegant hypothesis to consider.
- OnCusp licenses oncology candidates and develops human evidence.
- CUSP06, its lead ADC, targets CDH6 and remains experimental.
- Its reported financing totals $139 million; the business depends on clinical execution and future partnerships.
A company built for the middle act
The founders brought complementary habits to the problem. Bing Yuan had worked in oncology strategy and business development. Eric Slosberg came from translational development at Daiichi Sankyo. Andy Fu brought business-development experience from CStone Pharmaceuticals. Together, they established OnCusp in 2021, with operations in the United States and China. The ambition was specific: acquire promising candidates before human proof, establish that proof, and seek partners to carry them toward commercialization.
This makes OnCusp a developer and prospective licensing counterparty. Patients are its intended beneficiaries; pharmaceutical companies are prospective downstream commercial partners. Upstream, it needs biotechnology firms and researchers willing to entrust it with an asset. It occupies the space between inventing a molecule and possessing the evidence required to develop a medicine at scale.
The early friction was practical. Slosberg described replacing large-pharma resources with consultants while assembling an internal team. The founders also confronted a worsening biotech financing market. Those experiences offer a useful lesson for other founders: match the organization to the next decision it must earn. Borrowing specialist expertise can help a small team attempt work that requires more disciplines than its payroll contains.
The molecule arrived with a contract
In June 2022, OnCusp announced its agreement with Multitude Therapeutics for AMT-707, subsequently called CUSP06. OnCusp obtained development and commercialization rights outside Greater China. Multitude would receive an upfront payment, development and regulatory milestones, sales milestones and tiered royalties. The arrangement divides territory and financial rewards while putting the clinical-development work into experienced hands.
Manufacturing was another division of labor: WuXi XDC was named the chemistry, manufacturing and controls partner. An antibody-drug conjugate is a complicated object to reproduce reliably. A clinical plan needs a dependable supply of the same drug, batch after batch. The partner network is therefore part of the product’s practical development, rather than decorative company biography.
a candidate02Generate
human evidence03Seek the
next partner
An antibody carrying eight payloads
CUSP06 is an antibody-drug conjugate, or ADC: a targeting antibody joined to a cell-killing payload. The antibody recognizes cadherin-6, abbreviated CDH6. This protein is expressed in several cancers, notably ovarian and renal cancers. CUSP06 carries exatecan, a topoisomerase-1 inhibitor, through a protease-cleavable linker. Its drug-to-antibody ratio is eight.
antibody
payloads
The design also seeks a bystander effect: released payload can affect neighboring cancer cells, including those with less of the target. Published preclinical experiments demonstrated that effect in mixed-cell models and antitumor activity in several CDH6-expressing models. The distinction matters. A laboratory mechanism provides a reason to conduct a trial; it cannot settle whether the resulting treatment offers patients a favorable balance of benefit and harm.
OnCusp’s other publicly listed program, CUSP02, is an early-discovery bispecific antibody intended to combine immune-targeting and anti-angiogenic activity. It remains much earlier than CUSP06. The current company story is consequently driven by the ADC’s progress.
Read the denominator
That progress now includes human results. On October 5, 2026, OnCusp announced Phase 1b ovarian-cancer findings presented at IGCS. At the September 23 cutoff, the 4.0 mg/kg cohort recorded 13 responses among 21 evaluable patients, an objective response rate of 62%. Across the four reported dose cohorts, rates ranged from 40% to 62%.
Four cohorts. Four response rates.
The study included 86 heavily pretreated ovarian-cancer patients, with 81 evaluable for efficacy. Response and durability data were still maturing. Tumor shrinkage is meaningful evidence, but it is not a survival result or proof of superiority to another treatment. The excitement belongs alongside the study’s size and design.
Safety also deserves its own sentence. The IGCS presentation, using an earlier July cutoff across 191 Phase 1a and 1b participants, recorded grade 3 or worse treatment-related adverse events in 51.8% and one fatal febrile-neutropenia event at 5.6 mg/kg. Dose modifications were chiefly driven by hematologic effects. Choosing a dose is a benefit-and-risk decision, not a contest to deliver the most payload.
The money buys a test
OnCusp began with a $25 million seed round, added $14 million in Seed Plus financing, and completed a $100 million Series A in December 2023, announced the following January. Novo Holdings, OrbiMed and F-Prime Capital co-led the Series A. Proceeds were intended to support CUSP06’s clinical proof of concept and expand the portfolio and team. Financing measures the resources committed; it does not measure what the program has cost.
“It is always about the people.”Andy Fu, co-founder, April 2022
There is competition at the same target. Daiichi Sankyo and Merck are developing the CDH6-directed raludotatug deruxtecan in REJOICE-Ovarian01. OnCusp must establish the value of its own design through clinical evidence. Comparing percentages from separate trials cannot do that job.
FDA Fast Track designation, announced for CUSP06 in February 2025, supports development; the drug remains investigational. For patients and clinicians, the practical route is the trial record and an eligibility discussion. For biotechnology partners, OnCusp offers a development relationship. Both audiences ultimately need the same thing from this middle act: evidence sturdy enough to justify the next one.