Merck’s sac-TMT Phase 3 win is the most important ADC data point since Enhertu’s early breast cancer approval last week. Sacituzumab tirumotecan, an antibody-drug conjugate co-developed with China’s Kelun-Biotech, significantly improved both progression-free survival and overall survival versus chemotherapy in advanced or recurrent endometrial cancer. The Pharma Letter called it “a potentially important new growth driver as it prepares for future competition to blockbuster immunotherapy Keytruda.” The win validates three converging trends simultaneously: ADCs continue to expand beyond breast cancer into new tumor types, the China licensing model continues to produce registrational-quality assets, and Merck’s post-Keytruda pipeline build is producing results. Meanwhile, Truist Securities projected that Revolution Medicines could receive FDA approval for daraxonrasib in second-line pancreatic cancer by the end of Q3 2026, calling the company one that “is evolving into a major revenue-generating oncology company.” Full Phase 3 data will be presented at the ASCO plenary on May 31—11 days from today. Regeneron pivoted after its LAG-3 miss with a novel Antibody-Helicon Conjugate partnership. The FDA accepted the NDA for asundexian, the first Factor XIa inhibitor for stroke prevention. And federal ethics disclosures revealed stock purchases in Lilly and West Pharmaceutical Services made on Trump’s behalf between January and March.
Top Story: Merck’s sac-TMT Hits Phase 3 in Endometrial Cancer
What Happened: Merck reported positive Phase 3 results for sacituzumab tirumotecan (sac-TMT), an antibody-drug conjugate co-developed with China’s Kelun-Biotech, in advanced or recurrent endometrial cancer. The drug significantly improved both progression-free survival and overall survival versus investigator’s choice chemotherapy. BioSpace noted the companies “have yet to specify when they plan to file for approval.”
The Science: Trop-2 in a New Tumor Type
sac-TMT targets Trop-2, the same antigen targeted by Gilead’s Trodelvy (sacituzumab govitecan), but uses a different linker-payload combination. The tirumotecan payload is designed to deliver a potent cytotoxic effect with a potentially improved therapeutic window compared to earlier Trop-2 ADC designs. Kelun-Biotech developed the molecule and licensed global rights outside China to Merck.
The endometrial cancer readout expands the validated tumor types for Trop-2 ADCs beyond the breast and urothelial cancers where Trodelvy is already approved. Endometrial cancer is one of the most common gynecologic malignancies, and patients with advanced or recurrent disease have limited treatment options after first-line therapy. A drug that demonstrates both PFS and OS improvement versus chemotherapy in this setting has a compelling regulatory submission package—dual survival endpoints provide the strongest possible basis for approval.
Why This Matters for Merck’s Pipeline Strategy
Merck faces one of the largest single-product patent cliffs in pharmaceutical history as Keytruda approaches loss of exclusivity in 2028. The company has been systematically building an ADC portfolio through its Kelun-Biotech partnership to help replace Keytruda revenue. The sac-TMT Phase 3 win is the most advanced and most commercially significant readout from that effort to date.
A filing in H2 2026 would position sac-TMT for a potential approval in 2027, giving Merck a new commercial asset before the full force of the Keytruda cliff arrives. For a company that needs multiple growth drivers to offset the loss of the world’s most prescribed cancer immunotherapy, every validated late-stage asset is a building block in the post-Keytruda architecture.
The China Licensing Validation Continues
The Merck/Kelun-Biotech partnership is now one of the most productive China-to-West licensing deals alongside BMS/Hengrui ($15.2 billion, 13 programs), Lilly/Hengrui (via Kailera), GSK/SiranBio ($1 billion ALK7), and AbbVie/Haisco. The pattern is consistent and accelerating: Chinese pharmaceutical companies are producing clinical-stage assets across oncology, immunology, metabolic disease, and cardiometabolic categories that Western pharma companies find strategically valuable.
Kelun-Biotech in particular has emerged as one of China’s leading ADC developers, with a technology platform capable of generating multiple clinical-stage candidates across different antigen targets. For Merck, the partnership provides access to a pipeline of ADC assets at a cost structure that is meaningfully lower than developing them internally. The economics of the model—Chinese development at lower cost, Western commercialization at global scale—create value for both sides. The geopolitical risks (BIOSECURE Act debates, Section 232 tariffs, China’s Decree No. 834) have not slowed deal flow. If anything, the clinical results flowing from these partnerships are strengthening the case for continued engagement.
Our Pro brief analyzes how sac-TMT fits the post-Keytruda pipeline rebuild, where the Kelun-Biotech partnership ranks in the China licensing wave, and how the endometrial cancer data positions against Gilead’s Trodelvy in the Trop-2 ADC competitive landscape. [Details below.]
What to Watch
The filing timeline is the immediate question. The companies have not specified when they plan to submit for approval, but the dual PFS/OS endpoint hit gives them a registration-ready dataset. A filing announcement in H2 2026 would put sac-TMT on track for a 2027 approval. Watch for the regulatory submission announcement and for additional tumor-type data from the broader Kelun-Biotech ADC collaboration.
Truist Projects Revolution Medicines Approval by End of Q3
What Happened: Truist Securities issued a note calling Revolution Medicines a company that “is evolving into a major revenue-generating oncology company” and projected an FDA approval for daraxonrasib in second-line pancreatic cancer by the end of Q3 2026.
What the Projection Implies
If Revolution files under the CNPV program as planned, the 50-day Foundayo precedent suggests approval could come within weeks of filing. Truist’s Q3 timeline implies Revolution files its NDA shortly after—or concurrently with—the ASCO plenary presentation on May 31. A month after the Phase 3 readout, Truist said the company has moved from a clinical-stage biotech to “a major revenue-generating oncology company” in the eyes of the Street.
An August or September 2026 approval would make daraxonrasib one of the fastest oncology drugs from Phase 3 readout to market in recent FDA history. But this projection carries an important caveat: the CNPV program is operating without its champion. Commissioner Makary, who created and drove the CNPV, resigned last week. Interim CDER head Høeg departed days later. Acting Commissioner Diamantas comes from the food side of the agency. Whether the CNPV continues to operate at the pace that produced Foundayo’s 50-day approval is an open question that directly affects Revolution’s timeline.
The ASCO plenary session on May 31 remains the most anticipated oncology presentation of the year. Full Phase 3 data—including PFS (not yet disclosed), subgroup analyses, and mature survival curves—will be presented. The data will determine whether the investment thesis transitions from “promising clinical-stage” to “imminent commercial launch.” The presentation is 11 days away.
Our Pro brief models what Truist’s projection means for the CNPV filing timeline, assesses the risk that the leadership transition delays the program, and lays out the revenue implications of a Q3 2026 versus mid-2027 approval scenario. [Details below.]
Regeneron Partners with Parabilis on Novel Antibody-Helicon Conjugates
What Happened: Regeneron announced a strategic research collaboration with Parabilis Medicines to develop Antibody-Helicon Conjugates (AHCs), a novel therapeutic class combining antibodies with Parabilis’s Helicon peptide platform to target historically undruggable proteins. The Pharma Letter noted the focus on “challenging and historically ‘undruggable’ targets.”
A Strategic Pivot After the LAG-3 Miss
BioSpace reported the deal came “right after reporting a major Phase 3 LAG-3 miss” in melanoma, suggesting Regeneron is diversifying its pipeline after the fianlimab setback. The timing is telling. Regeneron’s immuno-oncology strategy was built around combining its Libtayo PD-1 inhibitor with fianlimab’s LAG-3 blockade. When that combination missed Phase 3 last week, it left a strategic gap in Regeneron’s oncology growth narrative.
The Parabilis deal does not fill that gap immediately—AHCs are early-stage research, not clinical-stage assets. But it signals that Regeneron is looking beyond traditional antibody combinations to build the next generation of its oncology portfolio. AHCs targeting proteins that conventional antibodies and small molecules cannot reach could expand the druggable proteome in ways that open entirely new therapeutic categories. For a company whose core competence is antibody engineering, expanding into novel conjugate formats is a natural extension of its platform capabilities even as it represents a longer-term strategic bet.
FDA Accepts Asundexian NDA for Stroke Prevention
What Happened: The FDA and Japan’s Ministry of Health accepted New Drug Applications for asundexian, an investigational Factor XIa inhibitor, for prevention of ischemic stroke in patients after non-cardioembolic ischemic stroke or transient ischemic attack.
Why Factor XIa Matters
Factor XIa inhibitors represent a fundamentally new class of anticoagulants. Current standard-of-care therapies for stroke prevention—including direct oral anticoagulants like apixaban (Eliquis) and rivaroxaban (Xarelto)—reduce stroke risk but carry a meaningful bleeding risk that limits their use in some patient populations. Many patients who would benefit from anticoagulation are not treated because their physicians judge the bleeding risk too high.
Factor XIa inhibitors are designed to address this limitation by separating anticoagulation from bleeding: reducing pathological clot formation through a pathway that is less involved in hemostasis, the body’s natural bleeding-control mechanism. If approved, asundexian would be the first Factor XIa inhibitor on the market. The commercial implications are significant given the size of the anticoagulation market. A next-generation anticoagulant that offers comparable stroke prevention with a meaningfully better bleeding profile could expand the treated population substantially by reaching patients who are currently undertreated.
This is also relevant to the Eliquis patent cliff. Eliquis is projected to lose the vast majority of its revenue as patents expire later this decade. Asundexian and the Factor XIa class represent the kind of next-generation therapy that could define the post-Eliquis anticoagulation landscape for the companies and patients who adopt them. The NDA acceptance means the FDA review clock is now running, and the regulatory outcome will determine whether Factor XIa inhibitors move from a promising mechanism to a validated commercial reality.
Policy Note: Trump Ethics Disclosure Includes Pharma Stock
Federal ethics disclosures released May 14 show that stock purchases of up to $680,000 in Eli Lilly and up to $500,000 in West Pharmaceutical Services (a GLP-1 injectable device manufacturer) were made on President Trump’s behalf between January and March 2026. The purchases were part of broader trades across the economy including tech, aerospace, and consumer companies. The Trump Organization has said in the past that neither the president nor his children play a role in “selecting, directing, or approving” specific investments. The disclosure was first reported by KFF Health News.
Why This Matters: The purchases coincided with a period in which multiple policy actions benefited Lilly’s GLP-1 franchise, including the Foundayo CNPV designation and filing, the Medicare GLP-1 Bridge program finalization, and the MFN pricing deals with 17 pharmaceutical companies. We present this as factual disclosure for our readers’ consideration without characterizing intent. The Trump Organization has consistently maintained that the president does not select or approve specific trades. The timeline and the policy actions are notable, and our readers in the industry should be aware of the disclosure as it may generate Congressional or media scrutiny that touches on the broader pharma policy environment in the coming weeks.
Strategic Themes
1. ADCs Are Now Validated Across Multiple Tumor Types and Treatment Settings
Enhertu in early breast cancer last week. sac-TMT in endometrial cancer this week. The ADC modality is demonstrating clinical utility that extends far beyond the metastatic breast cancer setting where it first proved itself. Each new tumor type validation and each expansion into earlier treatment settings increases the total addressable market for ADC therapies and reinforces the strategic rationale behind the industry’s massive investment in the space—from Gilead’s $5 billion Tubulis acquisition to Merck’s Kelun-Biotech partnership to Daiichi Sankyo’s $14.6 billion oncology plan.
2. The China Licensing Model Is Producing Registrational-Quality Data
sac-TMT’s dual PFS/OS hit in Phase 3 is the latest example of a Chinese-developed asset generating the kind of data that supports a global regulatory filing. BMS/Hengrui, Lilly/Hengrui, GSK/SiranBio, AbbVie/Haisco, and now Merck/Kelun-Biotech have all executed deals that are either producing or expected to produce registration-ready clinical data. The model is no longer experimental. It is a validated pipeline strategy that large pharma companies are using systematically.
3. Revolution’s Q3 Approval Projection Depends on CNPV Continuity
Truist’s timeline assumes the CNPV program operates at the pace Makary established. If it does, daraxonrasib could be approved within weeks of its ASCO plenary presentation. If the CNPV stalls during the leadership transition, standard NDA review timelines (10 to 12 months) would apply, pushing approval into mid-2027. The gap between those two scenarios represents significant deferred revenue for Revolution and delayed access for pancreatic cancer patients with no effective second-line options.
4. Factor XIa Could Reshape the Anticoagulation Market as Eliquis Faces Its Cliff
Asundexian’s NDA acceptance positions it as potentially the first drug in a new class that addresses the primary limitation of current anticoagulants: bleeding risk. If the clinical profile confirms the mechanism’s promise—comparable stroke prevention with less bleeding—the drug could expand the treated population beyond what Eliquis and Xarelto reach today while capturing share from those drugs as they face patent expiration.
Frequently Asked Questions
What is sac-TMT?
Sacituzumab tirumotecan, an antibody-drug conjugate co-developed by Merck and China’s Kelun-Biotech targeting Trop-2. Phase 3 data showed significant improvement in both progression-free survival and overall survival in advanced or recurrent endometrial cancer versus chemotherapy. Filing timeline has not been specified.
How does sac-TMT compare to Trodelvy?
Both target Trop-2, but sac-TMT uses a different linker-payload combination (tirumotecan payload). The endometrial cancer data positions sac-TMT in a tumor type where Trodelvy is not approved. No head-to-head clinical comparisons exist.
When could Revolution Medicines get approved?
Truist projects FDA approval by end of Q3 2026 if Revolution files under the CNPV program. The 50-day Foundayo precedent suggests approval could come within weeks of filing. Full Phase 3 data will be presented at the ASCO plenary on May 31. The projection depends on the CNPV program continuing to operate during the FDA leadership transition.
What is asundexian?
An investigational Factor XIa inhibitor for stroke prevention. The FDA accepted its NDA. If approved, it would be the first Factor XIa inhibitor on the market, offering anticoagulation with potentially less bleeding risk than current therapies like Eliquis and Xarelto.
What is the Regeneron/Parabilis deal?
A research collaboration focused on Antibody-Helicon Conjugates, a novel therapeutic class targeting historically undruggable proteins. The deal came immediately after Regeneron’s fianlimab Phase 3 miss in melanoma, signaling pipeline diversification beyond traditional antibody combinations.
What do the Trump ethics disclosures show?
Stock purchases of up to $680,000 in Lilly and up to $500,000 in West Pharmaceutical Services made on Trump’s behalf between January and March 2026, part of broader trades across the economy. The Trump Organization says the president does not direct specific investments. The purchases coincided with policy actions benefiting Lilly’s GLP-1 franchise.
When is ASCO?
May 29 through June 2 in Chicago. Revolution Medicines plenary session May 31. Full Phase 3 RASolute 302 data including PFS, subgroup analyses, and mature survival curves. The conference is 11 days away.
BioMed Nexus Pro — What Institutional Subscribers Are Reading Today
Merck’s Post-Keytruda ADC Build. We map sac-TMT alongside Merck’s broader Kelun-Biotech ADC portfolio, assess how the endometrial cancer data positions against Gilead’s Trodelvy, and model what a 2027 approval would contribute to Merck’s post-Keytruda revenue replacement effort.
Revolution Medicines ASCO Preview. We lay out what the full Phase 3 dataset needs to show beyond the topline OS result, model the CNPV filing timeline and the Q3 approval scenario, and assess what the transition from clinical-stage to “major revenue-generating oncology company” means for launch preparation and commercial infrastructure.
Factor XIa: The Anticoagulation Reset. We analyze why asundexian could reshape the post-Eliquis landscape, model the addressable population expansion from reduced bleeding risk, and assess the competitive dynamics as the class develops.
Plus: Trump disclosure policy implications, Regeneron pipeline pivot assessment, China licensing scorecard update, ASCO 11-day countdown, and the updated catalyst calendar through H2 2026.
About BioMed Nexus
BioMed Nexus delivers institutional-grade intelligence to biotech and pharma executives, investors, and clinicians. Our daily briefings and deep-dive analyses cut through the noise to deliver the strategic insights that drive better decision-making in the life sciences.
Subscribe to receive daily updates and gain access to BioMed Nexus Pro institutional intelligence briefs.
