The distance between a $63 billion acquisition and a small biotechnology company can be measured in more than headcount. It is the distance between selecting a bet and living inside it. Jay Stamatis knows the first job intimately. For more than eight years, he led AbbVie’s Business Development and Acquisitions team, helping shape a vast pipeline across oncology, immunology and neuroscience. In 2025, he chose the second job: chief executive of MBrace Therapeutics, a focused company with two antibody-drug conjugates in clinical testing and a taste for biology that others have not yet crowded.
His announcement was strikingly free of coronation language. Stamatis said he was “excited and humbled” to work with the MBrace team and board. The emphasis sat where it often does in his public remarks - on colleagues, collective work and the next piece of evidence. A CEO title can be presented as an arrival. His reads more like a handoff at speed.
A historian among probabilities
Stamatis did not begin with the degree one might expect from an oncology executive. He earned a BA in History from Tulane University, then an MBA from Washington University in St. Louis. History is good training for people who must act before the archive is complete. Motives conflict. Evidence arrives unevenly. The same event looks different depending on where one stands. Biotech business development simply adds assays, patent estates, clinical clocks and expensive consequences.
His career became a tour through the institutions that built modern biotechnology. There were commercial and business-development roles at Eli Lilly and Amgen. He worked at Onyx Pharmaceuticals until Amgen acquired it, then at Acerta Pharma, the oncology startup that became part of AstraZeneca. At Atara Biotherapeutics, a cell-therapy company, he served as vice president of business development. Each stop offered another version of the same puzzle: which science could become a product, which product could become a company, and which partnership could move it farther than either party could alone?
From commercial rooms to the corner office
Then came AbbVie. From 2016 through 2025, Stamatis led Business Development and Acquisitions. The work ranged from product-development collaborations and option agreements to technology platforms and outright acquisitions. His team was also woven into strategy for AbbVie’s core therapeutic areas. The headline transaction was the 2019 agreement to acquire Allergan for $63 billion, an undertaking so large that the word “deal” sounds almost quaint.
What the dealmaker learned
The popular picture of M&A is theatrical: the late-night call, the number written on a board, the handshake before the market opens. The durable work is less cinematic. Teams compare mechanisms, trial design, manufacturing, intellectual property and the many varieties of “maybe.” They decide which uncertainty deserves capital and which attractive story does not survive inspection.
At a biotechnology conference in early 2024, Stamatis observed that the M&A environment had “kind of woken up a little bit.” The modest phrasing suits the craft. Markets do not ring an alarm clock. They shift by degrees, and dealmakers must distinguish a genuine opening from a room full of people repeating that one has arrived. Later that year, on a New York stage, he discussed opportunity selection and the art of getting a deal across the finish line. Selection comes first for a reason.
“I’m excited and humbled to be working with such an accomplished and committed MBrace Therapeutics team and board of directors.”Jay Stamatis, announcing his move to MBrace
That accumulated pattern recognition is now pointed inward. At AbbVie, a single program could be judged in the context of an enormous portfolio. At MBrace, choices are more exposed. Hiring, financing, trial execution and platform priorities meet in the same hallway. The operating lesson is almost rude in its simplicity: every “yes” spends time that cannot be bought back.
The case for unfamiliar biology
MBrace was founded in 2020 around a particular frustration. Antibody-drug conjugates, or ADCs, had improved through better linkers, payloads and manufacturing, but the industry still needed useful new targets. Proven targets attract competition. They also leave certain tumors and resistance mechanisms outside the map.
An ADC is a precise delivery arrangement: an antibody recognizes a protein on a tumor cell, carries a linked drug to that cell and is pulled inside, where the payload is released. The elegance depends on the address. A target must be reachable, sufficiently associated with tumor tissue and able to internalize its cargo. Find the wrong address and even a beautifully engineered package has nowhere useful to go.
MBrace’s answer is SPARTA, a discovery approach that screens in living systems. The company uses it to look for tumor-specific, accessible and internalizing targets, then selects antibodies against them. The deliberate gamble is on novel biology. MBrace accepts the risk that comes with a less familiar target in exchange for the possibility of entering territory that has not already filled with competitors.
Two clinical tests, not two victory laps
The lead program, MBRC-101, targets EphA5, a receptor expressed across multiple solid tumors. Its first-in-human study began dosing in late 2023. Phase 1 has since been completed, and the broader Phase 1/1b/2 study continues to evaluate safety, dosing, pharmacokinetics and preliminary activity. The program’s path from preclinical models into a multicenter trial is meaningful progress. It is still a study, with the disciplined uncertainty that word requires.
A second program, MBRC-201, entered a recruiting Phase 1/2 study in 2025. Behind those sit additional discovery and IND-enabling programs. For Stamatis, the portfolio offers two simultaneous tests. The molecules must generate interpretable clinical evidence. The platform must show that it can keep producing candidates rather than merely explaining the first one after the fact.
This is where the CEO’s old and new jobs overlap. A business-development leader learns to ask whether an asset is differentiated, whether the evidence is decision-grade and whether the next milestone creates options. An operator must create the conditions for those answers to arrive. Capital needs a calendar. Scientific ambition needs a protocol. A platform needs programs that leave the slide deck.
Novelty is not a trophy. At a clinical-stage company, it is a hypothesis with a schedule.
A smaller table, a longer horizon
MBrace’s public language under Stamatis favors collaboration and long-term thinking. When the company formed a scientific advisory board, he highlighted members who had helped establish ADCs and precision oncology, and welcomed the chance to learn from them. It is a useful tell. Leaders with extensive deal experience can be caricatured as people who move pieces. Stamatis talks like someone attentive to the people who understand why the pieces behave as they do.
That attention also reveals a connection running through his career. At Onyx and Acerta, he saw focused oncology companies become part of larger organizations. At Atara, he worked around the demands of a new therapeutic modality. At AbbVie, he could compare innovations across three major therapeutic areas. MBrace gathers those lessons into one compact assignment: protect the scientific premise, invite outside expertise early and keep enough strategic flexibility to respond when the data complicate the original plan. Clinical development rarely rewards vanity. It rewards teams willing to revise the map without forgetting the destination.
Away from work, his company biography sketches an ordinary counterweight to corporate scale. He lives in the Chicago area with his wife, Jean, and their three sons. He cycles, prefers being outdoors and shows up for youth sports. Cycling is an irresistible metaphor for biotech, so it is best handled sparingly. Still, both reward pacing, honest feedback and the humility to notice the hill before it notices you.
His career has already crossed acquired startups, global pharmaceutical companies, cell therapy, oncology and one of the industry’s defining mega-deals. MBrace may be the most personal test because the abstraction has fallen away. The target choices are the company’s choices. The clinical milestones belong to his team. The next financing, partnership or development decision cannot disappear into the machinery of a vast portfolio.
That does not make the smaller company simpler. It makes cause and effect easier to see. Stamatis arrives with a history major’s comfort around incomplete records and a dealmaker’s habit of comparing futures. Now he has to help make one of them real. Two programs are in the clinic. More sit behind them. The evidence will set the pace, and the person who once helped decide which external bets AbbVie should make is finally living inside a bet of his own.