Leadership in Rare Tumors: Merck KGaA to Acquire SpringWorks Therapeutics

In a joined statement, German-based Merck KGaA, which operates as EMD Group in the United States and Canada, and includes EMD Serono (healthcare), MilliporeSigma (life science), and EMD Electronics (electronics), and Connecticut-based commercial-stage biopharmaceutical company SpringWorks Therapeutics, confirmed that the companies have entered into a definitive agreement in which Merck KGaA, acquires SpringWorks.

The purchase price of US $47 per share in cash represents an equity value of approximately US $3.9 billion, or an enterprise value of $ US 3.4 billion (€3.0 billion) based on SpringWorks’ cash balance as of December 31, 2024, and a premium of 26% to SpringWorks’ unaffected 20-day volume-weighted average price of US $37.38 on February 7, 2025, the day prior to the first market speculation of a potential transaction between Merck KGaA and SpringWorks.

“The agreed acquisition of SpringWorks is a major step in our active portfolio strategy to position our company as a globally diversified, innovation and technology powerhouse. For our Healthcare sector, it sharpens the focus on rare tumors, accelerates growth, and strengthens our presence in the U.S.,” noted Belén Garijo, Chair of the Executive Board and CEO of Merck KGaA, Darmstadt, Germany.

“Beyond this planned transaction, we will continue to explore M&A opportunities across our three complementary business sectors, always with a firm focus on strategic fit, financial robustness, and long-term value creation,” Garijo added.

Business development/M&A priorities
The planned transaction is fully aligned with the business development/M&A priorities of the Healthcare business of Merck KGaA, as outlined during the company’s Capital Markets Day in October 2024: to continue to pursue external innovation via in-licensing of high-quality compounds at various stages of development and focused acquisitions that promise early value creation.

According to the companies joint ststement, the acquisition also fits with the strategic objective of strengthening the presence of the Healthcare business of Merck KGaA in the United States, the world’s largest pharmaceutical market.

Upon closing, the business combination will immediately contribute to the revenues of Merck KGaA, and is expected to be accretive to the company’s earnings per share pre (EPS pre) in 2027. The acquisition will be funded with available cash and new debt. Beyond this planned transaction, Merck KGaA, will retain the ability to pursue larger transactions and continue to evaluate opportunities across its three sectors, with Life Science a priority. Merck KGaA, is committed to preserving its strong investment grade credit rating.

Standard-of Care
SpringWorks’ rare tumor portfolio includes nirogacestat (Ogsiveo®), a marketed first-in-class, systemic standard-of-care therapy for adults with desmoid tumors and the first and only oral, selective, small molecule gamma secretase inhibitor (GSI) that is approved in the U.S. for use in adults with progressing desmoid tumors who require systemic treatment.

Nirogacestat is also in Phase 2 clinical development for adult patients with ovarian granulosa cell tumors and is being evaluated as part of several B-cell maturation agent (BCMA) combination therapy regimens in collaboration with industry and academia.

Desmoid tumors
Desmoid tumors, also known as desmoid-type fibromatosis or aggressive fibromatosis, are a rare, aggressive soft-tissue tumor characterized by locally invasive growth, significant morbidity, and a high rate of recurrence. While this type of cancer is characterized by infiltrative growth, a tendency to recur, and significant morbidity, they do not metastasize. On average, Desmoid tumors, which are of mesenchymal origin, affects a small proportion of the population with an incidence of 2 to 4 patients per million, primarily impact younger people.[1]

Clinical trials are underway to evaluate nirogacestat for pediatric patients with desmoid tumors.

MEK inhibitor
SpringWorks’ portfolio also includes mirdametinib (Gomekli™), an oral, small molecule MEK inhibitor that is approved by the U.S. FDA for the treatment of adult and pediatric patients 2 years of age and older with neurofibromatosis type 1 (NF1) who have symptomatic plexiform neurofibromas (PN) not amenable to complete resection.

Mirdametinib inhibits MEK1 and MEK2, which occupy pivotal positions in the MAPK pathway, a key signaling network that regulates cell growth and survival that plays a central role in multiple cancers and rare diseases when dysregulated. [2]

The U.S. FDA’s February 2025 approval of mirdametinib was based on positive data from SpringWorks’ Phase 2b ReNeu trial (NCT03962543), which demonstrated that mirdametinib treatment resulted in a robust objective response rate, deep and durable reductions in tumor volume, and a manageable safety profile. With the approval, SpringWorks was granted a rare pediatric disease priority review voucher by the U.S. FDA.

The marketing authorization application for mirdametinib has been validated by the European Medicines Agency (EMA) with a potential approval in 2025. In addition, SpringWorks is advancing its pipeline with additional programs in other tumor settings that are currently underserved.

Mirdametinib is also in development for the treatment of pediatric low-grade glioma (LGG). 

Sustainable revenue
The expectation is that nirogacestat will accelerate immediate and sustainable revenue growth for Merck KGaA.

SpringWorks’ marketing authorization application (MAA) for nirogacestat is under review with the European Medicines Agency (EMA), with a Committee for Medicinal Products for Human Use (CHMP) decision expected in Q2 2025.

SpringWorks’ portfolio complements the progress of Merck KGaA, in rare tumors, with Merck KGaA, recently exercising an option for worldwide commercialization rights for pimicotinib (ABSK021), an investigational, oral, highly potent and selective small molecule inhibitor of CSF-1R developed by Abbisko Therapeutics Co. for patients with tenosynovial giant cell tumor (TGCT).

TGCT is a non-malignant, benign, yet aggressive and often recurring rare soft tissue tumor which involves the synovial lining of joints, bursae, and tendon sheaths that can cause high morbidity associated with swelling, pain, stiffness, and limited mobility of the affected joints, significantly impacting daily activities and health related Quality of Life (hrQoL). If left untreated or in recurrent cases, TGCT can result in irreversible damage to the bone, joint and surrounding tissues, highlighting the need for well-tolerated and effective systemic treatments that can impact tumor growth while relieving the symptoms of the disease. [3]

Leadership in rare tumors
“We have the unique opportunity with SpringWorks to establish a leadership position in rare tumors and build a strong foundation for further investments in this area, where a large unmet medical need exists,” said Peter Guenter, member of the Executive Board and CEO of Healthcare at Merck KGaA.

“Together, our company and SpringWorks are the perfect combination to improve outcomes for patients with rare tumors and bring therapeutic innovations to more patients worldwide while building on and reinforcing the early success of SpringWorks in the United States. For us, the planned acquisition will create long term, sustainable growth for our Healthcare business. Along with my successor Danny Bar-Zohar, we look forward to completing this strategic transaction and making a meaningful difference for patients whose lives are so profoundly affected by these complex and challenging tumors.”

Reach into markets beyond the U.S
The agreed acquisition provides SpringWorks with an opportunity to expand its reach into markets beyond the U.S. and leverage the breadth of resources of the global Healthcare organization of Merck KGaA.

“From the outset, our focus at SpringWorks has been to create transformative solutions for patients suffering from serious diseases. We have successfully launched two best-in-class medicines in the United States, and with the aspiration to deliver our therapies worldwide, our journey is at a pivotal juncture. It became clear during our discussions with the team of Merck KGaA, that we share many core values, including a commitment to help more patients with rare tumors live longer, better lives,” explained Saqib Islam, Chief Executive Officer of SpringWorks Therapeutics and a founding member of the company’s executive team since its launch in 2017.

“We believe that by joining forces with Merck KGaA, we are not only creating significant, immediate value for our stakeholders, but we will also be able to leverage their resources and expertise to build a brighter future for the patient communities we seek to serve while also creating new opportunities for SpringWorks employees as part of a global organization,” added Islam, who, prior to joining SpringWorks, was Chief Business Officer at Moderna Therapeutics, where he oversaw critical aspects of the company’s growth, including global strategic planning, corporate development and business development.

Unanimously approval
The transaction has been unanimously approved, by all those in attendance, by both the Merck KGaA and SpringWorks Boards of Directors and is expected to close in the second half of 2025, subject to satisfaction of customary closing conditions, including approval of SpringWorks’ shareholders and receipt of required regulatory approvals.

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Clinical trials
Study of Cryoablation and Nirogacestat for Desmoid Tumor – ClinicalTrials.gov ID NCT05949099
Evaluation of the Response and Non-response of Nirogacestat in Desmoid Tumors- Clinical Study – ClinicalTrials.gov ID NCT05879146
Individual Patient Compassionate Use of Nirogacestat – ClinicalTrials.gov ID NCT05041036
Nirogacestat for Adults With Desmoid Tumor/​Aggressive Fibromatosis (DT/​AF) (DeFi) – ClinicalTrials.gov ID NCT03785964
A Study of a New Drug, Nirogacestat, for Treating Desmoid Tumors That Cannot be Removed by Surgery – ClinicalTrials.gov ID NCT04195399
Mirdametinib Monotherapy in Adults With Neurofibromatosis 1 (NF1) and Cutaneous Neurofibromas (cNF). (Mirda) – ClinicalTrials.gov ID NCT06159166
MEK Inhibitor Mirdametinib (PD-0325901) in Patients With Neurofibromatosis Type 1 Associated Plexiform Neurofibromas (ReNeu) – ClinicalTrials.gov ID NCT03962543

Highlights of prescribing information
Nirogacestat (Ogsiveo®; Springworks Therapeutics) [Prescribing Information]
Mirdametinib (Gomekli™; Springworks Therapeutics)[Prescribing Information]

References
[1] Master SR, Mangla A, Shah C. Desmoid Tumor. [Updated 2024 Mar 1]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK459231
[2] Moertel CL, Hirbe AC, Shuhaiber HH, Bielamowicz K, Sidhu A, Viskochil D, Weber MD, Lokku A, Smith LM, Foreman NK, Hajjar FM, McNall-Knapp RY, Weintraub L, Antony R, Franson AT, Meade J, Schiff D, Walbert T, Ambady P, Bota DA, Campen CJ, Kaur G, Klesse LJ, Maraka S, Moots PL, Nevel K, Bornhorst M, Aguilar-Bonilla A, Chagnon S, Dalvi N, Gupta P, Khatib Z, Metrock LK, Nghiemphu PL, Roberts RD, Robison NJ, Sadighi Z, Stapleton S, Babovic-Vuksanovic D, Gershon TR; ReNeu Trial Investigators; ReNeu Study Investigators. ReNeu: A Pivotal, Phase IIb Trial of Mirdametinib in Adults and Children With Symptomatic Neurofibromatosis Type 1-Associated Plexiform Neurofibroma. J Clin Oncol. 2025 Feb 20;43(6):716-729. doi: 10.1200/JCO.24.01034. Epub 2024 Nov 8. Erratum in: J Clin Oncol. 2025 Jan 10;43(2):239. doi: 10.1200/JCO-24-02561. PMID: 39514826; PMCID: PMC11825507.
[3] Choi WS, Lee SK, Kim JY, Kim Y. Diffuse-Type Tenosynovial Giant Cell Tumor: What Are the Important Findings on the Initial and Follow-Up MRI? Cancers (Basel). 2024 Jan 17;16(2):402. doi: 10.3390/cancers16020402. PMID: 38254890; PMCID: PMC10814250.

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