If You Invested in Springworks Therapeutics, Inc. (SWTX)

SpringWorks Therapeutics, Inc. (historically Nasdaq: SWTX) is a commercial-stage biopharmaceutical company that has focused on developing and commercializing targeted therapies for patients with severe rare diseases and cancer. According to company disclosures, SpringWorks developed and commercialized OGSIVEO® (nirogacestat) as the first and only U.S. Food and Drug Administration (FDA) approved medicine for adults with desmoid tumors, and GOMEKLI™ (mirdametinib) as the first and only FDA-approved medicine for both adults and children with neurofibromatosis type 1 associated plexiform neurofibromas (NF1-PN). The company has also described itself as advancing a portfolio of novel targeted therapy product candidates for patients with additional rare tumors and hematological cancers.

SpringWorks has reported that it is a commercial-stage biopharmaceutical company dedicated to improving the lives of patients with rare tumors and other severe conditions. Its work has centered on rare, locally aggressive tumors and genetic disorders that can cause significant pain, functional impairment and reduced quality of life. Desmoid tumors and NF1-PN, the initial focus of its approved medicines, are examples of such conditions.

Core therapies and disease focus

OGSIVEO (nirogacestat) is described as an oral, selective, small molecule gamma secretase inhibitor. Company communications state that it is approved in the United States and the European Union as monotherapy for the treatment of adult patients with progressing desmoid tumors who require systemic treatment. SpringWorks has also noted that the FDA and the European Medicines Agency (EMA) have granted Orphan Drug designation for OGSIVEO for the treatment of desmoid tumors.

Desmoid tumors are characterized in SpringWorks materials as rare, locally aggressive tumors of the soft tissues that can be serious, debilitating and, in rare cases when vital structures are impacted, life-threatening. They are described as having high recurrence rates after surgical resection and as conditions where experts and treatment guidelines now recommend systemic therapies as first-line intervention for most tumor locations requiring treatment.

GOMEKLI / EZMEKLY (mirdametinib) is described by the company as an oral, small molecule MEK inhibitor. SpringWorks reports that GOMEKLI is approved by the FDA for the treatment of adult and pediatric patients 2 years of age and older with NF1 who have symptomatic plexiform neurofibromas not amenable to complete resection. In the European Union, the medicine is marketed under the brand name EZMEKLY® and has received conditional marketing authorization for symptomatic, inoperable plexiform neurofibromas in pediatric and adult patients with NF1 aged 2 years and above. Company disclosures state that the FDA and the European Commission have granted Orphan Drug designation for mirdametinib for the treatment of NF1.

NF1 is described in SpringWorks communications as a rare genetic disorder arising from mutations in the NF1 gene, with a heterogeneous clinical course that can involve tumor growth and neurological complications. Plexiform neurofibromas are described as tumors that grow in an infiltrative pattern along the peripheral nerve sheath, can cause severe disfigurement, pain and functional impairment, and may be difficult or impossible to remove completely by surgery.

Clinical development and research

SpringWorks has highlighted several pivotal clinical trials supporting its therapies. For nirogacestat, the company cites the Phase 3 DeFi trial, a global, randomized, multicenter, double-blind, placebo-controlled study in adults with progressing desmoid tumors. Company announcements describe DeFi as having met its primary endpoint of improving progression-free survival compared to placebo, with significant improvements in objective response rate and patient-reported outcomes. Long-term follow-up data from DeFi have been reported to show further reductions in tumor size, increased objective response rates, sustained symptom improvement and a consistent safety profile with longer-term treatment.

For mirdametinib, SpringWorks points to the Phase 2b ReNeu trial, an ongoing, multi-center, open-label, single-arm study in pediatric and adult patients with NF1-PN. The company reports that ReNeu met its primary endpoint of confirmed objective response rate, with deep and durable reductions in target tumor volume and early, sustained improvements in pain and quality of life in both adults and children. These data formed the basis for the FDA approval of GOMEKLI and for regulatory reviews in the European Union.

Beyond its approved medicines, SpringWorks has described a broader pipeline that includes product candidates for additional rare tumors and hematological cancers, as well as early-stage programs such as a pan-TEAD inhibitor in Hippo-mutant solid tumors and a molecular glue targeting specific Protein Phosphatase 2A (PP2A) complexes in molecularly defined subsets of uterine cancer. These descriptions come from company news releases outlining ongoing Phase 1 and Phase 1b trials and licensing arrangements.

Corporate status and ownership

Historically, SpringWorks Therapeutics, Inc. traded on the Nasdaq Stock Market under the ticker symbol SWTX. On July 1, 2025, according to a Form 8-K filed with the U.S. Securities and Exchange Commission (SEC), Merck KGaA, Darmstadt, Germany completed the previously announced acquisition of SpringWorks pursuant to an Agreement and Plan of Merger. The filing states that a wholly owned subsidiary of Merck KGaA, Darmstadt, Germany merged with and into SpringWorks, with SpringWorks surviving as a wholly owned subsidiary of Merck KGaA, Darmstadt, Germany. As a result of the merger, each share of SpringWorks common stock outstanding immediately prior to the effective time was cancelled and converted into the right to receive cash consideration, and a change in control of SpringWorks occurred.

On the same date, SpringWorks notified Nasdaq of the consummation of the merger and requested that Nasdaq file a Form 25 to remove the company’s common stock from listing and registration under Section 12(b) of the Securities Exchange Act of 1934. A Form 25 filed by Nasdaq on July 1, 2025 identifies SpringWorks Therapeutics, Inc. and its common stock and indicates that the class of securities is being struck from listing and registration on Nasdaq. Subsequently, on July 11, 2025, SpringWorks filed a Form 15 with the SEC to terminate registration of its common stock under Section 12(g) of the Exchange Act and to suspend its duty to file reports under Sections 13 and 15(d). The Form 15 notes that the approximate number of holders of record as of the certification date was one.

These regulatory filings indicate that SpringWorks is no longer a publicly traded company and that its reporting obligations as an independent issuer under the Exchange Act have been suspended. The SWTX ticker therefore represents a former listing, and SpringWorks operates as a wholly owned subsidiary of Merck KGaA, Darmstadt, Germany.

Regulatory and safety information

Company communications about OGSIVEO and mirdametinib include detailed safety and prescribing information. For OGSIVEO, SpringWorks highlights warnings and precautions related to diarrhea, ovarian toxicity, hepatotoxicity, non-melanoma skin cancers, electrolyte abnormalities and embryo-fetal toxicity, as well as common adverse reactions such as diarrhea, ovarian toxicity, rash, nausea, fatigue, stomatitis, headache, abdominal pain, cough, alopecia, upper respiratory tract infection and dyspnea. The company also notes potential interactions with CYP3A inhibitors and inducers and gastric acid reducing agents.

For GOMEKLI / mirdametinib, SpringWorks communications emphasize warnings and precautions related to ocular toxicity, left ventricular dysfunction, dermatologic adverse reactions and embryo-fetal toxicity. The most common adverse reactions reported in adults include rash, diarrhea, nausea, musculoskeletal pain, vomiting and fatigue, with similar but age-appropriate profiles reported in pediatric patients. These safety summaries are drawn from the company’s press releases and references to full prescribing information.

Position within rare tumor therapeutics

Across its public statements, SpringWorks consistently characterizes its mission as improving the lives of patients with rare tumors and other severe diseases through targeted therapies. The company’s development and commercialization of OGSIVEO for desmoid tumors and GOMEKLI / EZMEKLY for NF1-PN, along with its ongoing research programs in additional tumor settings, form the core of its business description as presented in its news releases, financial updates and regulatory communications.