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Genmab: Europe's Antibody Pioneer
In the fall of 2024, something remarkable happened in the usually understated world of Danish biotechnology. Genmab—a company that most American investors had never heard of—quietly announced it was preparing to acquire Merus N.V. for approximately $8 billion. It was one of the largest biotech acquisitions ever in Europe, funded by a company that barely existed twenty-five years earlier and had nearly collapsed during the 2008 financial crisis.
The numbers tell part of the story: Genmab expects its 2025 revenue to be in the range of $3.3–3.7 billion, compared to $3.1 billion in 2024, with projected revenue growth driven by higher royalties, net product sales, and collaboration revenue. But numbers alone can't capture the improbability of Genmab's journey—from a Medarex spin-off in Copenhagen to Europe's most valuable biotechnology company, powered by intellectual property that now generates royalties on every dollar of an $11.7 billion-per-year cancer drug.
This is the story of how platform thinking, partnership-driven commercialization, and a stubborn focus on antibody science created one of biotechnology's most successful royalty machines—and how that same company is now betting billions to evolve into something much bigger.
The Antibody Science Primer: Why Genmab's Technology Matters
Before diving into corporate history, understanding why antibodies represent such a powerful therapeutic platform is essential. The human immune system deploys antibodies as precision-guided missiles, each designed to recognize and neutralize specific foreign invaders. When scientists figured out how to manufacture antibodies in the laboratory—and engineer them to target cancer cells rather than pathogens—they unlocked one of medicine's most transformative technologies.
The evolution of therapeutic antibodies reads like a chronicle of incremental scientific breakthroughs. Early antibodies came from mice, which meant the human immune system often recognized them as foreign and mounted an allergic response. Scientists then developed chimeric antibodies (part mouse, part human), followed by humanized antibodies (mostly human with some mouse sequences). But the holy grail was fully human antibodies—therapeutic proteins that the human body would accept as its own.
Genmab's foundational technology was licensed from Medarex to create fully human high-affinity antibodies using transgenic mice. These antibodies are less likely to elicit an allergic reaction and other side effects compared with other types of man-made antibodies containing other animal proteins because the IgG antibodies produced have human proteins.
This matters because side effects determine whether a cancer patient can stay on treatment long enough for it to work. A drug that triggers allergic reactions or immune responses becomes unusable precisely when patients need it most. Fully human antibodies solved this problem and opened the door to long-term treatment regimens that would have been impossible with earlier antibody generations.
What separates a "platform" company from a single-product company is the ability to repeatedly generate new therapeutic candidates from a core technological capability. A platform company doesn't just find one drug—it creates the tools to discover many drugs, then either develops them internally or licenses them to partners who can bring them to market. As Jan van de Winkel explained: "We've been able to create two completely new next-generation antibody technology platforms, DuoBody and HexaBody for bispecific and immune effector function enhanced antibodies respectively, which are very strongly anchored in science via peer-reviewed publications."
For investors, the platform model offers compounding returns: each successful product validates the platform, which attracts more partnerships, which generates more royalties, which funds more R&D, which creates more products. When it works, the flywheel effect is powerful. When it doesn't—when the platform fails to generate commercial hits—the whole edifice collapses.
Genmab's story is about what happens when the flywheel starts spinning.
Origins: The Medarex Spin-Off Story (1998–2000)
The founding of Genmab contains all the elements of a classic biotech origin story: a visionary scientist with academic credentials, venture capital backing from an unlikely source, and a strategic calculation about how to extract more value from an existing technology platform.
Genmab was founded as a European spin-off of American biotech company Medarex in February 1999. Danish investment firm BankInvest, under Florian Schönharting, provided the seed investment for the company to start up in Copenhagen.
The man who would become Genmab's enduring leader entered through the back door. Jan G. J. van de Winkel has over 25 years of experience in the therapeutic antibody field and served as Vice President and Scientific Director of Medarex Europe prior to Genmab. He is the author of over 300 scientific publications and has been responsible for over 70 patents and pending patent applications. Dr. van de Winkel holds a professorship of immunotherapy at Utrecht University.
Van de Winkel's academic pedigree mattered. He holds a PhD in Immunology from Utrecht University in the Netherlands, where he honed his expertise in the field. His academic achievements laid a strong foundation for his future endeavors in the biotechnology industry. Unlike many biotech founders who come from business backgrounds and hire scientists, van de Winkel understood the biology of antibodies at a fundamental level—knowledge that would prove crucial when Genmab needed to develop its own proprietary technologies after the initial Medarex license.
Van de Winkel later recalled: "The Genmab research team evolved out of a team that was already formed and led by me at Medarex Europe, part of Medarex in the US. That team worked with making fully human antibodies with transgenic mice. Creating Genmab with the help of a group of investors in Europe allowed for a key change in direction. While Medarex kept focusing on the technology platform itself, we took the technology and built a new company that is very much product-focused."
This strategic positioning—product-focused rather than platform-focused—would define Genmab's trajectory. Medarex was essentially a toolmaker, licensing its transgenic mouse technology to pharmaceutical companies who wanted to develop their own antibody drugs. Genmab would use those tools to build actual products, capturing more of the value chain while accepting more of the development risk.
The company's first CEO was Lisa N. Drakeman, Ph.D., who had been a vice president at Medarex and was married to Donald Drakeman, Medarex's CEO and President at the time. The family connections were not unusual in the incestuous world of early biotech, where human capital was scarce and trust networks determined deal flow.
The company went public in October 2000, earning DKK 1.56 billion, and had a second public offering in January 2006, yielding DKK 800 million. The 2000 IPO was record-breaking for a European biotech at the time—a sign of both the dot-com era's enthusiasm for anything technology-related and genuine excitement about Genmab's scientific platform.
The Utrecht R&D hub anchored Genmab's research capabilities in one of Europe's most productive immunology ecosystems. The company's initial R&D location was a nine-story building in Utrecht Science Park, in the Netherlands; this was replaced with an "R&D Center" also in Utrecht, in June 2018. By mid-2019, this new facility was at capacity, and plans were set afoot to build an adjacent, connected facility.
For investors looking at early-stage biotechs, the lesson from Genmab's founding is clear: scientific credibility matters. Van de Winkel wasn't just a manager who could read balance sheets—he was a world-class immunologist who could evaluate antibody candidates at the molecular level. When technical decisions needed to be made about which programs to advance and which to terminate, he could make them from first principles rather than relying entirely on advisors.
Early Years & Near-Death Experience (2001–2010)
If the founding story sounds triumphant, the next decade was anything but. Genmab's early years were a masterclass in how quickly things can go wrong in biotechnology—and how much survival depends on adaptability under extreme pressure.
By 2001, Medarex and Genmab had come back together in a drug development partnership, which highlighted the manufacturing deficit and clinical development expertise of Genmab relative to Medarex. In 2005, the Biotechnology Industry Organization (BIO) and the Long Island Life Sciences Initiative honored Genmab with a James D. Watson Helix Award.
The early recognition masked growing problems. Genmab had programs but lacked the infrastructure to develop them efficiently. The company needed manufacturing capacity, clinical development expertise, and a partner with deep pockets. It thought it had found all three.
In December 2006, Genmab entered a deal with GlaxoSmithKline to co-develop and commercialize ofatumumab, a drug that could be used for treatment in CD20 positive B-cell chronic lymphocytic leukemia, follicular non-Hodgkin's lymphoma, rheumatoid arthritis and other indications. The agreement gave Genmab a license fee of DKK 582 million (US$102 million) and GSK bought 4,471,202 shares of Genmab for DKK 2,033 million (US$359 million). The potential value of this agreement could be DKK 12.0 billion (US$2.1 billion) if all milestones were reached.
The GSK deal looked transformational. A major pharmaceutical company had validated Genmab's science, invested hundreds of millions of dollars, and committed to a development program that could generate billions in milestone payments. With this capital, Genmab made a fateful decision.
2008 saw the company purchasing a 22,000-litre, 36-acre antibody manufacturing plant in Brooklyn Park, Minnesota from PDL BioPharma, with plans to retain all 170 employees thereat.
The timing could not have been worse.
During the 2008 financial crisis, GlaxoSmithKline exited oncology, which impacted co-development of ofatumumab, an oncology-directed product. In tandem with the sale of the plant, the company reorganized and planned to dismiss about 300 employees. Selling the facility was difficult due to the Great Recession; by 2012, Genmab wrote-off the entire facility from the company's balance sheets.
As van de Winkel later reflected: "How about completely writing off a $240 million manufacturing facility acquired just two years previously. Try renegotiating an agreement with a Big Pharma, knowing that if they don't play ball your company could be staring at a dire financial outlook. Imagine cutting hundreds of jobs when blockbuster success seems right around the corner. Many will likely be surprised to learn how close Genmab came to walking through death's door."
"GSK had made up its mind to move out of oncology, which was too bad because Arzerra (ofatumumab) [the drug the companies had been codeveloping] was an oncology product," he asserts.
The crisis forced an existential reckoning. GSK's strategic pivot meant Genmab's lead program had lost its partner's commitment. The manufacturing plant was draining cash. Capital markets were frozen. The company needed a rescue—and van de Winkel delivered one.
Van de Winkel, along with a few colleagues and a GSK team headed by Slaoui, started on a Wednesday. "By Friday afternoon of that same week, we were popping champagne to celebrate the renegotiated relationship," van de Winkel attests. By the following week, Genmab was able to announce having received a payment from GSK of roughly $135 million, which helped financially stabilize the company. But the agreement also restructured Genmab's future funding commitment for the development of ofatumumab in oncology indications, which were capped at $25 million annually for the next six years. "I wanted to maximize the investment from Genmab into Arzerra per year and in total for oncology, so we were willing to give back some of the rights for autoimmune indications, reduce royalties from 20 to 10 percent, and give up some milestone payments related to autoimmune development."
As of 2002, Drakeman remained in the CEO role, but by 2010 she had announced her retirement. In 2010, Jan Van de Winkel, a co-founder of the firm, was appointed as President and CEO of Genmab.
Van de Winkel later explained: "In 2010 the Board asked me to step up to be the CEO and, it felt like the right time for me so I could refocus the company and make it less dependent on the stock market—because due to the financial crisis in 2008 raising funds via the stock market for a biotech company would be difficult if not impossible."
A sale of the facility to Baxter International came in February 2013. Following the failed strategy of in-housing manufacturing, Genmab chose to thereafter completely outsource both manufacturing and the conduct of clinical trials.
The near-death experience taught Genmab lessons that would define its strategy for the next decade: don't vertically integrate into manufacturing, partner with companies that have aligned strategic interests, and maintain financial flexibility above all else. Van de Winkel emerged from the crisis with credibility and a mandate to rebuild.
The Technology Platform Strategy
The company that emerged from the 2008–2010 crucible was fundamentally different from the one that entered it. Rather than relying solely on the original Medarex technology, Genmab invested heavily in developing proprietary platforms that would generate ongoing value regardless of what happened to any individual drug program.
The DuoBody platform is an innovative platform for the discovery and development of bispecific antibodies that may improve antibody therapy of cancer, autoimmune, infectious and central nervous system disease. Bispecific antibodies bind to two different epitopes either on the same, or on different targets (also known as dual-targeting) which may improve the antibodies' specificity and efficacy in inactivating the disease targets. DuoBody molecules are unique in combining the benefits of bispecificity with the strengths of conventional antibodies which allows DuoBody molecules to be administered and dosed as other antibody therapeutics. Genmab's DuoBody platform generates bispecific antibodies via a fast and broadly applicable process which is easily performed at standard bench, as well as commercial, manufacturing scale.
HexaBody technology, a broadly applicable antibody platform from Genmab, allows for the creation of potent therapeutics by inducing antibody hexamer formation (clusters of six antibodies). The HexaBody platform builds on natural antibody biology and enhances complement-mediated killing (complement-dependent cytotoxicity (CDC)), allowing antibodies with limited or absent CDC to be transformed into potent cytotoxic antibodies. The HexaBody technology creates opportunities to explore new product candidates, to repurpose drug candidates unsuccessful in previous clinical trials due to insufficient potency and may provide a useful strategy in product life cycle extension. The HexaBody technology can be directed to any antigen or target, including those implicated in cancer and infectious diseases. The HexaBody technology can be combined with Genmab's DuoBody platform as well as other antibody technologies.
DuoHexaBody combines the dual targeting of Genmab's DuoBody technology with the enhanced potency of HexaBody. This creates bispecific antibodies that are also able to form antibody-target clusters required for antibody functionality.
What made Genmab unusual was its willingness to publish openly about its technologies. In an industry where secrecy is the default, van de Winkel chose transparency. The logic was counterintuitive but sound: by publishing the science, Genmab attracted collaborators, established scientific credibility, and created a rising tide that lifted all boats working on similar approaches. The company retained proprietary advantages through know-how and manufacturing expertise even while sharing the basic science.
As van de Winkel described the portfolio: "About 80% of our pipeline is based on DuoBody and another 10% on HexaBody; the remaining 10% are Genmab antibodies conjugated to toxins—ADCs, that is."
The platform approach generated multiple partnership opportunities. Under the original July 2012 agreement with Janssen, Janssen has the right to use the DuoBody technology to create panels of bispecific antibodies (up to 10 DuoBody programs) to multiple disease target combinations. Genmab received an upfront payment of $3.5 million from Janssen and will potentially be entitled to milestone and license payments of up to approximately $175 million, as well as royalties for each program. Genmab received an initial payment of $2 million from Janssen. For each of the ten additional programs that Janssen successfully initiates, develops and commercializes, Genmab will potentially be entitled to receive average milestone and license payments of approximately $191 million.
BioNTech and Genmab also expanded their global strategic collaboration to develop and commercialize novel immunotherapies for the treatment of cancer patients. Under this expansion, BioNTech and Genmab will jointly work to research, develop and commercialize novel monospecific antibody candidates for various cancer indications. Since 2015, the companies have been working on the joint development of bispecific cancer antibodies aimed at improving immunotherapy options for cancer patients.
For long-term investors, the platform approach offered multiple shots on goal. Any single drug program might fail, but a validated platform with multiple partners increased the probability that something would eventually succeed. And when something did succeed—when daratumumab became Darzalex—the returns were extraordinary.
Inflection Point #1: The Daratumumab/Darzalex Breakthrough (2012–2015)
Every biotech company dreams of partnering a drug that becomes a blockbuster. Genmab partnered one that became a mega-blockbuster—a therapy so successful that it would generate enough royalty revenue to fund the entire company's transformation from a clinical-stage operation to a commercial enterprise.
On August 30, 2012, Janssen Biotech, Inc., one of the Janssen Pharmaceutical Companies of Johnson & Johnson, announced that it had executed a global license and development agreement with the Danish company Genmab A/S for the anti-cancer compound, daratumumab. Daratumumab (HuMax-CD38) is a human CD38 monoclonal antibody currently in Phase I/II studies in relapsed, refractory multiple myeloma.
J&J finalized a pact to in-license a promising antibody from Genmab, taking an $80 million equity stake along with a $55 million upfront. The total deal, including potential milestones, hit $1.1 billion. Daratumumab targets the CD38 molecule found on multiple myeloma cells, proving promising in preclinical work for a range of hematological cells.
"We are very pleased to partner with Janssen on another Genmab innovation and look forward to working with them to accelerate the development of daratumumab and to maximize the value of this product," said CEO Jan van de Winkel.
The deal structure was crucial. Pursuant to this agreement, Genmab receives tiered royalty payments of 12% to 20% based on Janssen's annual net product sales and is eligible for certain additional payments in connection with development, regulatory and sales milestones. DARZALEX is commercialized by Janssen Biotech, Inc., under an exclusive development, manufacturing and commercialization agreement entered into in 2012. Janssen is fully responsible for developing and commercializing daratumumab and all costs associated therewith.
This was the partnership model that would define Genmab's strategy: create innovative compounds, partner them to pharma companies with development and commercial capabilities, and collect royalties in perpetuity. Genmab retained no manufacturing burden, no sales force expense, no regulatory filing costs. It simply created the molecule and received a percentage of every dollar sold.
Genmab's lead product, daratumumab, marketed as DARZALEX for the treatment of certain multiple myeloma indications, is a human IgG1k monoclonal antibody that binds with high affinity to the CD38 molecule, which is highly expressed on the surface of MM cells. When first approved by the FDA in 2015, it was the first human CD38-targeting mAb to reach the market and the first mAb to receive FDA approval to treat multiple myeloma.
When Darzalex launched, few anticipated how dominant it would become. Multiple myeloma is a deadly blood cancer affecting over 30,000 Americans annually, and existing treatments left enormous unmet need. Darzalex worked differently—and better—than what came before.
DARZALEX (daratumumab), Janssen's CD38-targeting monoclonal antibody, has transformed multiple myeloma treatment across all lines of therapy, generating $11.6 billion in worldwide sales in 2024. The drug's success stems from its versatility in combination regimens, expanded approvals for both newly diagnosed and relapsed/refractory patients, and the introduction of DARZALEX FASPRO, a convenient subcutaneous formulation. Despite growing competition from emerging therapies like Sanofi's SARCLISA and novel BCMA-targeting agents, DARZALEX maintains market leadership through first-mover advantage and robust clinical efficacy data.
Darzalex became the number 4 blockbuster biologic in 2024, just behind Keytruda, Dupixent and Skyrizi. However, the patent holder of Darzalex expects that royalties from sales of DARZALEX will begin to decline materially in 2029 following expiration of U.S. patent rights on daratumumab, assuming constant underlying sales of DARZALEX.
Analysts at GlobalData forecast that sales of Darzalex will peak at $16.8 billion in 2029. From this point onwards, they will decline, hitting a value of $15.5 billion in 2031.
The trajectory from $55 million upfront to $11.7 billion annual sales represents one of the most successful biotech licensing deals in history. For Genmab, collecting 12–20% royalties on those sales transformed the company's financial profile and validated the entire platform approach.
Inflection Point #2: The AbbVie Partnership & Epcoritamab (2020–2023)
If Darzalex proved that Genmab could create a blockbuster, the AbbVie deal showed the company could replicate the formula with its proprietary DuoBody platform—and this time, retain significantly more of the economics.
Genmab and AbbVie entered into a broad collaboration to jointly develop and commercialize three of Genmab's next-generation bispecific antibody products, including epcoritamab. The companies partnered to develop Genmab's next-generation bispecific antibody programs, epcoritamab (DuoBody-CD3xCD20), DuoHexaBody-CD37 and DuoBody-CD3x5T4. The collaboration combines Genmab's world-class discovery and development engine and next-generation bispecific antibody therapeutic candidates with AbbVie's deep clinical expertise, innovative antibody-drug conjugate platform and global commercial leadership in hematological cancers. The discovery research collaboration will combine proprietary antibodies from both companies along with Genmab's DuoBody technology and AbbVie's payload and ADC technology to select and develop up to four additional differentiated next-generation antibody-based product candidates, potentially across both solid tumors and hematological malignancies.
Under the terms of the agreement, AbbVie paid Genmab USD 750 million in upfront payment with the potential for Genmab to receive up to USD 3.15 billion in additional development, regulatory and sales milestone payments for all programs as well as tiered royalties between 22% and 26% on net sales for epcoritamab outside the U.S. and Japan. Except for these royalty-bearing sales, the parties share in pre-tax profits from the sale of products on a 50:50 basis. Included in these potential milestones are up to USD 1.15 billion in payments related to clinical development and commercial success across the three existing bispecific antibody programs. In addition, if all four next-generation antibody product candidates developed as a result of the discovery research collaboration are successful, Genmab is eligible to receive up to USD 2.0 billion in option exercise and success-based milestone payments.
The deal structure represented an evolution from the Darzalex model. Rather than pure royalties, Genmab would share profits 50:50 in the U.S. and Japan—the world's two largest pharmaceutical markets. This meant Genmab would book direct product sales rather than just royalty income, transitioning toward becoming a commercial company rather than purely a royalty recipient.
Global net sales of EPKINLY/TEPKINLY were USD 281 million in 2024. Net product sales in the U.S. and Japan by Genmab were DKK 1,743 million in 2024 compared to DKK 421 million in 2023. EPKINLY was approved in the U.S. in May 2023 and in Japan in September 2023.
AbbVie and Genmab's epcoritamab won accelerated approval to treat diffuse large B-cell lymphoma (DLBCL) after at least two lines of systemic therapy. The drug now bears the commercial moniker Epkinly. A CD20xCD3 T-cell engager, Epkinly belongs to a class of drugs that also includes Roche's first-to-market Lunsumio and its close-to-market glofitamab. So far, Epkinly's efficacy and safety data suggest it could be the best-in-class offering among CD20xCD3 bispecifics, William Blair analysts said in a December note. An SVB Securities team in February pegged Epkinly's peak sales in the U.S. across all potential indications at nearly $3 billion before an expected patent cliff in 2036.
In the third quarter of 2025, FDA granted Breakthrough Therapy Designation to Rina-S in advanced endometrial cancer, and the epcoritamab Phase 3 EPCORE FL-1 trial met dual primary endpoints of ORR and PFS, demonstrating statistically significant and clinically meaningful differences in both endpoints.
The bispecific antibody validation represented a critical milestone. Fourthly, as van de Winkel noted: "I am particularly proud that in May 2021 Janssen received regulatory approval for Rybrevant. Indicated for lung cancer, this is the very first therapy based on our DuoBody technology platform for creating bi-specific antibodies—on which over half our pipeline is based—to be approved. Janssen's parent company J&J recently advised that this could become a USD five billion peak sales product."
Inflection Point #3: Tivdak & The Cervical Cancer ADC (2021–2024)
While bispecific antibodies garnered most attention, Genmab was also building capabilities in antibody-drug conjugates (ADCs)—a technology that combines the targeting precision of antibodies with the cell-killing power of chemotherapy agents.
This FDA action converts the September 2021 accelerated approval of TIVDAK to a full approval. TIVDAK is the first antibody-drug conjugate (ADC) with demonstrated overall survival data to be granted full FDA approval in this patient population. The approval is based on results from the global, randomized, Phase 3 innovaTV 301 clinical trial, in which TIVDAK met its primary endpoint of overall survival (OS) in patients with previously treated recurrent or metastatic cervical cancer compared to chemotherapy.
Tisotumab vedotin is co-owned by Genmab and Pfizer, under an agreement in which the companies share costs and profits for the product on a 50:50 basis.
Pfizer took over Seagen's half of the deal when it bought the cancer-focused biotech in March 2023 for $43 billion. Based on a 24% objective response rate from the Phase II innovaTV 204 trial, the FDA granted Tivdak its accelerated approval in September 2021. As part of their obligations under the FDA's accelerated pathway—and to keep Tivdak on the market—Pfizer and Genmab ran the Phase III innovaTV 301 study, which ultimately became the basis for the full approval. The late-stage confirmatory trial, a randomized and open-label study that enrolled more than 500 patients who had undergone at most two prior rounds of systemic treatment, showed that the ADC could significantly boost survival versus chemotherapy.
According to GlobalData's Pharma Intelligence Center, Tivdak is forecast to generate $867 million in sales in 2030.
Tivdak represented an important strategic step. Cervical cancer is a gynecologic malignancy with limited treatment options for advanced patients—exactly the kind of underserved patient population where an innovative therapy can make meaningful commercial and clinical impact.
Inflection Point #4: The ProfoundBio Acquisition (2024)
After two decades of partnering drugs to larger companies, Genmab made a strategic pivot in 2024: it would start buying companies to build wholly owned programs. The first major acquisition signaled a transformation in corporate strategy.
Genmab announced that it has completed its acquisition of ProfoundBio, Inc., a clinical-stage biotechnology company developing next-generation antibody-drug conjugates (ADCs) and ADC technologies for the treatment of cancers in an all-cash transaction of USD 1.8 billion. "With the completion of this strategic transaction, we are excited to welcome our new colleagues and their expertise in developing next-generation antibody-drug conjugates to our exceptionally talented R&D team," said Jan van de Winkel, Ph.D., President and Chief Executive Officer of Genmab.
The acquisition gives Genmab worldwide rights to ProfoundBio's portfolio of next-generation ADCs, further broadening and strengthening its clinical pipeline. These programs include Rina-S, a potential best-in-class, clinical-stage, FRα-targeted, Topo1 ADC, currently in part 2 of a Phase 1/2 clinical trial, for the treatment of ovarian cancer and other FRα-expressing solid tumors. The addition of Rina-S to Genmab's portfolio enables Genmab to deepen its presence in the gynecologic oncology space and establish a firm foundation in solid tumors. Based on the data from the ongoing Phase 1/2 clinical trial, which also indicates that Rina-S has the potential to address a broader patient population than first-generation FRα-targeted ADCs, Genmab intends to broaden the development plans for Rina-S within ovarian cancer and other FRα-expressing solid tumors.
The buyout continues a surge in M&A for developers of antibody-drug conjugates and gives Genmab a potential competitor to a medicine AbbVie recently purchased in a multibillion-dollar acquisition. The field has also seen a flurry of acquisitions. In January, Johnson & Johnson agreed to pay $2 billion for Ambrx Biopharma. That followed the November announcement of AbbVie's $10 billion buyout of ImmunoGen. And in March last year, Pfizer inked a $43 billion deal to take over Seagen, one of the pioneers in the field.
The acquisition carried strategic risks—and legal complications that materialized quickly.
AbbVie Inc. filed a complaint against Genmab in the U.S. District Court for the Western District of Washington (Seattle). Genmab categorically refutes these allegations and will vigorously defend the company against AbbVie's claims. Genmab notes that this is yet another lawsuit among multiple recent lawsuits filed by AbbVie against competitors alleging misappropriation of its trade secrets by former AbbVie employees.
The alleged theft of trade secrets took place before Genmab acquired ProfoundBio. However, AbbVie is arguing Genmab should have known the biotech was built on its trade secrets. The lawsuit quotes Genmab executives discussing their high level of due diligence for the ProfoundBio buyout and notes that one executive said the innovative aspect of the ProfoundBio linker technology "is the very heavy use of sorbitol in order to increase the hydrophilicity." Such quotes informed AbbVie's allegation that "Genmab knew, reasonably had reason to know or was willfully blind" to the trade secrets.
While the lawsuit is pending, Genmab's collaboration with AbbVie related to epcoritamab will continue unaffected. "We remain fully committed to the epcoritamab broad clinical development program and our commercialization efforts."
The Darzalex Royalty Disputes with J&J (2020–2024)
Even successful partnerships can generate conflicts. The royalty dispute between Genmab and Johnson & Johnson over Darzalex illustrates how contract interpretation can affect billions in value—and how arbitration outcomes can diverge from expectations.
Johnson & Johnson scaled back its Darzalex royalty payments to Genmab in the second quarter of 2020, just as its new subcutaneous formulation was hitting the market. Genmab owed a portion of those royalties to drug delivery specialist Halozyme for its subQ technology, J&J argued. But Genmab didn't agree—and took the dispute into arbitration. Genmab, creator of Darzalex's original formulation, will take J&J and its Janssen unit to arbitration to determine whether the company must help cover Janssen's royalty payments to Halozyme, which developed the enzyme technology used in subcutaneous Darzalex Faspro.
There are two issues at play in the royalty dispute. The first has to do with whether J&J will continue to pay royalties once Genmab's Darzalex patents run out in the late 2020s and early 2030s. By majority opinion, the tribunal determined that J&J must pay royalties through the end of Genmab's last-held patent, but not the relevant J&J-owned patent, marking a win for the U.S. pharma giant. The other impasse is related to the royalty split between J&J, Genmab and Halozyme for the subcutaneous drug delivery tech developed by Halozyme, which is used in Darzalex's Faspro formulation. Around the middle of 2020, J&J dialed back its Darzalex royalty payments to Genmab, saying its partner should help chip in toward Halozyme payments. The tribunal on Thursday agreed that J&J can continue to reduce its royalty payments to Genmab to offset part of what it owes Halozyme.
In ruling against Genmab, the appeal arbitrator said that the company should have registered the claim in a previous arbitration between the companies. While sales for Johnson & Johnson's Darzalex continue to boom—as the company reported in its quarterly earnings presentation—the pharma major got more good news about its blockbuster. An appeal arbitrator rejected Genmab's claim that it is due additional milestone and royalty payments from Johnson & Johnson for Darzalex. The Danish biotech was hoping to overturn a 2-1 ruling in a second arbitration between the companies over Darzalex royalties. The decision exhausts Genmab's royalty claims against J&J.
For investors, the lesson is sobering. Even a $11.7 billion drug can become a source of legal conflict between partners, and arbitration outcomes are unpredictable. Contract language matters enormously when billions are at stake.
The Merus Acquisition: The $8 Billion Bet (2025)
In September 2025, Genmab announced its largest acquisition ever—a transformational deal that signals the company's ambition to become a global biotechnology leader with wholly owned commercial products.
Genmab announced to acquire Merus for USD 97.00 per share in an all-cash transaction representing a transaction value of approximately USD 8.0 billion. The USD 97.00 per common share purchase price payable in the tender offer represents a premium of approximately 41% over Merus' closing stock price on September 26, 2025, of USD 68.89 and approximately 44% over Merus' 30-day volume weighted average price of USD 67.42.
Petosemtamab is an EGFRxLGR5 bispecific antibody with the potential to be both first- and best-in-class in head and neck cancer. It has been granted two Breakthrough Therapy Designations (BTD) by the U.S. Food and Drug Administration (FDA) for first- and second-line plus head and neck cancer indications. Compelling Phase 2 data was presented at the American Society for Clinical Oncology (ASCO) 2025 Annual Meeting showing both an overall response rate and median progression free survival that were substantially higher than standard of care. Merus is currently running two Phase 3 trials in first- and second/third line head and neck cancer, with topline interim readout of one or both trials anticipated in 2026. Based on Genmab's experience in late-stage development and excellence in commercial execution, Genmab anticipates the potential for the initial launch of petosemtamab in 2027, subject to clinical results and regulatory approvals.
The transaction is not subject to a financing condition. Consideration is expected to be funded through a combination of cash on hand and approximately $5.5 billion of non-convertible debt financing. Genmab has obtained a funding commitment from Morgan Stanley Senior Funding, Inc. for this amount. The financing package includes a meaningful portion of prepayable debt, in line with Genmab's commitment to deleveraging with a target of gross leverage less than 3x within two years after the closing of the proposed transaction.
Genmab has blockbuster plans for petosemtamab. Once the candidate has completed a pair of ongoing phase 3 trials—which are due to read out next year—the biopharma is hoping to take petosemtamab to market in 2027. If it can get the green light for approval from regulators, Genmab envisages $1 billion in annual sales by 2029, with "multi-billion-dollar annual revenue potential thereafter." "The proposed acquisition of Merus clearly aligns with our long-term strategy. It has the potential to significantly accelerate our evolution into a global biotechnology leader by providing durable growth for the company well into the next decade," Genmab CEO Jan van de Winkel, Ph.D., said.
Genmab has entered into a definitive agreement to acquire Merus in an all-cash transaction for a total consideration of USD 8.0 billion, making it one of the largest acquisitions of a European biotech company to date.
On October 21, 2025, a wholly owned subsidiary of Genmab commenced a tender offer for 100% of Merus' common shares. The proposed transaction is anticipated to close by early in the first quarter of 2026, subject to the satisfaction of customary closing conditions for similar transactions.
Financial Performance & Revenue Dynamics
Genmab's revenue was DKK 21,526 million in 2024 compared to DKK 16,474 million in 2023. The increase of DKK 5,052 million, or 31%, was primarily driven by higher DARZALEX and Kesimpta royalties achieved under collaborations with J&J and Novartis, respectively.
Royalty revenue amounted to DKK 17,352 million in 2024 compared to DKK 13,705 million in 2023. The increase of DKK 3,647 million, or 27%, was primarily driven by higher DARZALEX and Kesimpta (ofatumumab) royalties achieved under daratumumab collaboration with J&J and ofatumumab collaboration with Novartis, respectively.
Operating profit was DKK 6,703 million in 2024 compared to DKK 5,321 million in 2023, an increase of DKK 1,382 million, or 26%.
Revenue was $2,662 million for the first nine months of 2025 compared to $2,198 million for the first nine months of 2024. The increase of $464 million, or 21%, was primarily driven by higher DARZALEX and Kesimpta royalties achieved under collaborations with Johnson & Johnson (J&J) and Novartis Pharma AG (Novartis), respectively, and higher EPKINLY net product sales. Royalty revenue was $2,219 million in the first nine months of 2025 compared to $1,802 million in the first nine months of 2024, an increase of $417 million, or 23%. The increase in royalties was driven by higher net sales of DARZALEX and Kesimpta.
Leadership and Culture: The Van de Winkel Approach
Jan van de Winkel's tenure as CEO illustrates how scientist-founders can successfully transition to operational leadership—when they possess both technical credibility and managerial adaptability.
In 2010, Jan van de Winkel was appointed CEO of Genmab. Under his leadership, the company has achieved remarkable growth and success. He has been pivotal in developing and commercializing several novel antibody therapies, significantly impacting patients' lives globally. Van de Winkel's leadership style is characterized by a strong emphasis on collaboration and innovation. He has fostered a culture of scientific excellence within Genmab, encouraging researchers to push the boundaries of what is possible.
As far as creative and strategic ways Genmab attempts to uphold that standard, van de Winkel describes the company's tactics as perhaps "unusual and a little bit unconventional" compared to other organizations of Genmab's size. He cites, for example, the "coffee meetings" he hosts biweekly with new employees—typically only five or six people at a time. "They can basically ask me about anything," he says. "And what we discuss in that room, stays in that room. That creates a very rapid and very good basis for trust and for connection between the new employees and myself. I keep hearing that most of them have never been with a company where they could have a lunch meeting or coffee with the CEO a month after they started."
Having transitioned from the often "individualistic or soloistic" nature of academic work, as van de Winkel describes it, to the collaborative world of biotech and drug development—both internally and externally—the Genmab CEO appreciates the opportunities he's afforded to impart a little wisdom and perspective to those coming up the ranks today. "What I always say is follow your passion and stay true to your core purpose," says van de Winkel. "You can hear that from me at all levels. At early stages in your career, you're easily distracted, of course, by other priorities or what people ask of you. I think to focus on your North Star is always really important."
Bull Case: Platform Power and Pipeline Depth
Porter's Five Forces Analysis:
The bull case for Genmab rests on several structural advantages embedded in the antibody therapeutics industry:
Barriers to Entry: Creating therapeutic antibodies requires specialized platforms, decades of accumulated know-how, and regulatory expertise. New entrants cannot easily replicate Genmab's DuoBody and HexaBody technologies, which are protected by patents and trade secrets. The company has filed over 70 patents and established manufacturing relationships that would take years for competitors to duplicate.
Supplier Power: Genmab has wisely outsourced manufacturing entirely, giving it flexibility to work with multiple contract manufacturers rather than being dependent on proprietary facilities. This reduces supplier bargaining power and capital intensity.
Customer/Partner Power: Large pharmaceutical companies like J&J and AbbVie are sophisticated buyers, but Genmab's differentiated technology creates switching costs. Once a pharma company has built development programs around DuoBody or HexaBody platforms, changing partners becomes prohibitively expensive.
Threat of Substitutes: While CAR-T therapies and other modalities compete for the same patients, bispecific antibodies offer advantages in manufacturing scale, administration convenience, and cost structure. The antibody format has proven remarkably durable across therapeutic areas.
Hamilton Helmer's 7 Powers Framework:
Scale Economies: As royalty income grows, Genmab's marginal cost approaches zero. Each additional dollar of Darzalex revenue generates high-margin royalty income with no incremental investment required.
Network Effects: Limited in traditional sense, but Genmab's platform approach creates partnership network effects—more validated products attract more partners, which generates more products.
Cornered Resource: Van de Winkel's scientific leadership, the Utrecht research hub, and two decades of accumulated antibody engineering expertise represent difficult-to-replicate human capital.
Process Power: Genmab's ability to repeatedly generate innovative antibody candidates from its platforms constitutes embedded process knowledge that competitors cannot easily observe or copy.
The bull case quantitatively centers on analysts forecasting that sales of Darzalex will peak at $16.8 billion in 2029, with Genmab collecting royalties on those sales while simultaneously ramping direct product revenue from EPKINLY and Tivdak. The Merus acquisition adds potential multi-billion-dollar petosemtamab revenue, and Rina-S could address the massive ovarian cancer market.
Bear Case: Concentration Risk and Patent Cliffs
The bear case starts with a simple observation: Genmab's revenue is dangerously concentrated.
The patent holder of Darzalex expects that royalties from sales of DARZALEX will begin to decline materially in 2029 following expiration of U.S. patent rights on daratumumab.
When Darzalex royalties decline post-2029, Genmab loses its largest revenue stream. The company must have newer products generating substantial revenue by then—EPKINLY, Tivdak, Rina-S, and petosemtamab need to collectively replace billions in annual royalty income. If any of these programs fail clinically or commercially, the transition becomes much more difficult.
Competitive Dynamics:
While DARZALEX faces competition from newer CD38-targeting antibodies like Sanofi's SARCLISA (isatuximab), it maintains significant market advantage through its first-mover position, extensive clinical data, and broader label indications. Competition is intensifying across Genmab's therapeutic areas. Bispecific antibodies from Roche, Regeneron, and others target the same patient populations as EPKINLY. ADC competition is fierce, with major players including AbbVie (after its ImmunoGen acquisition) and Pfizer (after Seagen) investing heavily.
Legal Overhang:
The AbbVie trade secret lawsuit represents material uncertainty. While Genmab has vowed to defend vigorously, an adverse outcome could compromise Rina-S development plans and damage the company's relationship with a key partner on EPKINLY.
Integration Risk:
The Merus acquisition is the largest in European biotech history, and Genmab is financing it with approximately $5.5 billion of non-convertible debt. This leverage adds financial risk to a company that has historically operated with minimal debt. If petosemtamab trials disappoint, Genmab faces both revenue shortfall and debt obligations.
Key Performance Indicators for Ongoing Monitoring
For investors tracking Genmab, three KPIs warrant close attention:
1. Darzalex Net Sales Growth: Since Genmab receives tiered royalties (12–20%) based on J&J's annual Darzalex sales, tracking J&J's quarterly Darzalex revenue provides direct insight into Genmab's largest revenue driver. Watch for any deceleration as generic competition approaches post-2029.
2. EPKINLY Net Product Sales Growth: This represents Genmab's transition from royalty-only to direct commercial revenue. Quarter-over-quarter growth rates indicate whether Genmab can successfully compete in the bispecific market and eventually replace declining Darzalex royalties.
3. Pipeline Clinical Milestones: For companies at Genmab's stage, binary clinical trial readouts drive substantial value. Key catalysts include petosemtamab Phase 3 results (expected 2026), Rina-S advancement decisions, and EPKINLY label expansions.
Myth vs. Reality
| Consensus Narrative | Reality Check |
|---|---|
| "Genmab is purely a royalty company" | Increasingly false. EPKINLY direct sales now approaching $300M annually, Tivdak profit-share ongoing, ProfoundBio and Merus acquisitions add wholly-owned programs |
| "The Darzalex patent cliff is existential" | Partially true. Darzalex royalties will decline post-2029, but Genmab has spent a decade building pipeline. Question is execution timing, not strategic direction |
| "European biotechs can't compete globally" | Demonstrably false. Genmab has created multiple blockbuster drugs, partnered with the world's largest pharma companies, and now makes transformational acquisitions |
| "The AbbVie partnership is stable" | Complicated. Epcoritamab collaboration continues, but the trade secret lawsuit creates tension. Both parties have incentives to compartmentalize |
Conclusion: The Platform That Kept Compounding
Twenty-six years after its founding, Genmab stands as arguably Europe's most successful biotechnology company—a remarkable achievement for an industry where the United States dominates. The company's journey from Medarex spin-off to near-bankruptcy to multi-billion-dollar acquirer illustrates both the fragility and potential of the platform model in biotechnology.
The company has 8 approved antibodies (monoclonal and bispecific) used in 8 marketed products, covering cancer indications and autoimmune diseases.
The next chapter will determine whether Genmab can successfully transition from a royalty-powered company to a fully integrated biopharmaceutical enterprise. The Merus acquisition signals ambitious intent; execution will determine whether that ambition was warranted.
As van de Winkel reflected on the company's progress: "We have made tremendous progress since 2015, building and expanding our capabilities. Today, Genmab has over 1200 employees across four international locations, all of which have been expanded in the support of our ambitious and growing business."
For long-term fundamental investors, Genmab presents a unique combination: proven platform technology, diversified partnership revenue, demonstrated ability to survive crises, and strategic ambition to own its destiny. The risks are substantial—patent cliffs, legal challenges, integration complexity—but so is the opportunity if the company executes its next phase of evolution.
The antibody pioneer from Copenhagen has proven it can create blockbusters. Now it must prove it can become one.
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