US WorldMeds Acquires Orbus Therapeutics, Expanding Commitment to Rare Diseases and Advancing Eflornithine in Adult Malignant Glioma

Acquisition builds on Phase 3 STELLAR study results showing clinically meaningful improvements in overall and progression-free survival in the subgroup of patients with recurrent IDH-mutant Grade 3 astrocytoma

LOUISVILLE, Ky. and MENLO PARK, Calif., Oct. 27, 2026 /PRNewswire/ -- US WorldMeds Ventures, LLC and Orbus Therapeutics, Inc. today announced a definitive merger agreement under which US WorldMeds has acquired Orbus, a privately held pharmaceutical company developing investigational eflornithine for rare and serious brain tumors. The transaction adds Orbus' late-stage program in recurrent Grade 3 astrocytoma to US WorldMeds' rare-disease portfolio. US WorldMeds made an undisclosed upfront payment to Orbus, which will also be eligible for development, regulatory, and sales-based milestone payments, plus tiered royalties on net sales in the U.S. Orbus is now a wholly owned subsidiary of US WorldMeds.

Eflornithine, also called DFMO, inhibits ornithine decarboxylase, or ODC, an enzyme involved in cellular division and proliferation that is known to become upregulated in certain cancers.  Orbus advanced oral eflornithine through the Phase 3 STELLAR study as a late-stage investigational therapy for recurrent Grade 3 astrocytoma, a rare and serious malignant glioma, and FDA granted the program Breakthrough Therapy designation for the treatment of anaplastic astrocytoma.

US WorldMeds currently commercializes IWILFIN® (eflornithine 192 mg tablets) for a separate rare oncology indication, providing established experience with the molecule and with therapies for underserved patient populations. This complementary experience positions US WorldMeds to build on Orbus' scientific and clinical work.

"The science and clinical results supporting eflornithine make this an especially exciting opportunity for US WorldMeds," said P. Breckinridge Jones, Chief Executive Officer of US WorldMeds. "We have built our company around bringing meaningful therapies to patients affected by difficult-to-treat and underserved diseases. The STELLAR study results provide a compelling foundation to build upon, and we believe our development and commercialization capabilities can help advance the program toward its next chapter."

Building on Phase 3 STELLAR Study results

The Phase 3 STELLAR study (n=343) evaluated eflornithine in combination with lomustine compared with lomustine alone in patients with recurrent Grade 3 astrocytoma based on the 2016 WHO classification. Although the study did not demonstrate a difference in overall survival between treatment arms in the overall intent-to-treat (ITT) study population, the study's primary endpoint, a subset analysis was planned to evaluate treatment effects in patients meeting the newly defined Grade 3 astrocytoma criteria per the 2021 WHO reclassification of brain tumors. The subset analysis, defined before unblinding, included patients with isocitrate dehydrogenase (IDH)-mutant, Grade 3 astrocytoma (n=196) and showed clinically meaningful improvements in overall survival and progression-free survival in the eflornithine plus lomustine arm versus lomustine alone. No benefit was observed in patients with Grade 4 tumors as defined by the updated 2021 classification.

In the IDH-mutant Grade 3 astrocytoma subset analysis:

• Median overall survival was 34.9 months for patients receiving eflornithine plus lomustine compared with 23.5 months for those receiving lomustine alone (hazard ratio of 0.64).
  
  
• Median progression-free survival more than doubled as determined by investigator assessment, reaching 15.8 months versus 7.2 months with lomustine alone (hazard ratio of 0.57).
  
  
• Grade 3 or higher treatment-emergent adverse events of note included myelosuppression (42% vs. 29%) and hearing impairment (24% vs. 0%).

The STELLAR study findings were subsequently published in the Journal of Clinical Oncology (Colman et al., 2026), adding peer-reviewed context to the observed survival outcomes in patients with recurrent IDH-mutant Grade 3 astrocytoma.

"Orbus has built a strong scientific and clinical foundation for eflornithine," said Jason Levin, former President and Chief Executive Officer of Orbus. "US WorldMeds brings the development expertise, commercial infrastructure and commitment to patients needed to advance the program."

Advancing the next chapter of eflornithine in gliomas

US WorldMeds intends to build on Orbus' scientific and clinical work by evaluating the development and regulatory path for eflornithine in recurrent IDH-mutant Grade 3 astrocytoma and other potential opportunities in adult malignant glioma.

"This transaction is an opportunity to build on Orbus' work and responsibly evaluate eflornithine's potential in adult malignant glioma," said Jones. "It reflects our continued commitment to pursuing medicines that may meaningfully improve outcomes for patients with serious diseases. We look forward to engaging with FDA about the best path to advance this program for patients living with this rare and challenging to treat disease."

About Eflornithine

Eflornithine, also called DFMO, irreversibly inhibits ornithine decarboxylase (ODC), the rate-limiting enzyme in polyamine synthesis. Cancer cells, including glioma cells, depend on elevated polyamine levels to sustain rapid growth, which makes ODC a rational therapeutic target.

US WorldMeds markets eflornithine 192 mg tablets as IWILFIN® for a separate rare oncology use.   Orbus's STELLAR trial results were achieved with an eflornithine oral solution which it has been developing for the treatment of recurrent Grade 3 astrocytoma.  

Eflornithine is investigational for use in the treatment of gliomas, including astrocytoma; its safety and efficacy for the treatment of glioma have not been established, and it is not approved by FDA or any other regulatory authority for this use.

WHAT IS IWILFIN?

IWILFIN is a prescription medicine used to reduce the risk of relapse in adults and children with high-risk neuroblastoma (HRNB) who have had at least a partial response to certain prior therapies.

IMPORTANT SAFETY INFORMATION

Before you take IWILFIN, tell your healthcare provider about your medical conditions, including if you have hearing problems, if you are pregnant or may become pregnant, or if you are breastfeeding.

If you or your partner are able to become pregnant, use effective birth control during treatment with IWILFIN and for 1 week after the last dose. Tell your healthcare provider right away if you or your partner become pregnant during treatment. Do not breastfeed during treatment with IWILFIN and for 1 week after the last dose.

IWILFIN can cause low blood cell counts. Tell your healthcare provider right away if you develop symptoms of low blood cell counts, including fever, easy bruising or bleeding, blood in your urine or stool, feeling unusually tired or weak, shortness of breath, or chills or shivering.

IWILFIN can cause liver problems. Tell your healthcare provider right away if you develop symptoms of liver problems, including your skin or white of your eyes turning yellow; dark urine; light-colored stools; nausea or vomiting; easy bruising or bleeding; loss of appetite; or pain, aching, or tenderness on the right side of your abdomen.

Hearing loss is common during treatment with IWILFIN and can be serious. Some people have needed to use hearing aids. Tell your healthcare provider right away if you get ringing in your ears or any new or worsening hearing loss.

What are the possible side effects of IWILFIN?

The most common side effects of IWILFIN in Study 3b included ear infection; diarrhea; cough; sinus infection; pneumonia; upper respiratory tract infection; pink eye; vomiting; stuffy, runny, itchy nose or sneezing; fever; skin infection; and urinary tract infection.

These are not all the possible side effects of IWILFIN. Contact your healthcare provider for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

About US WorldMeds

US WorldMeds is a U.S.-based specialty pharmaceutical company that develops and commercializes therapies for patients with rare and underserved conditions. The company's portfolio spans oncology and other specialty areas, with a focus on bringing meaningful treatment options to patients with significant unmet needs.

About Orbus Therapeutics

Orbus Therapeutics is a private pharmaceutical company founded by Bob Myers and Jason Levin based on the clinical work pioneered by Victor Levin, MD, Emeritus Professor of Neuro-Oncology. The company has been financially supported by leading healthcare institutional investors, including Longitude Capital, H.I.G. HealthBridge, Abingworth, Adams Street Partners and Agent Capital and other investors. Orbus focused on the development of therapies for rare diseases. Its lead product candidate is oral eflornithine, which has been studied in malignant glioma, including in the Phase 3 STELLAR study.

Forward-Looking Statements

This press release contains forward-looking statements, including statements regarding the development and regulatory path for eflornithine and the potential benefits of the transaction. These statements are based on current expectations and are subject to risks and uncertainties, including the outcome of discussions with FDA and other regulators and the results of any future clinical studies. Actual results may differ materially. US WorldMeds and Orbus undertake no obligation to update these statements except as required by law.

References

Colman, H., Lombardi, G., Wong, E. T., et al. (2026). STELLAR: Phase III, randomized, open-label study of eflornithine plus lomustine versus lomustine alone in patients with recurrent grade 3 astrocytoma. Journal of Clinical Oncology, 44(8), 641–652. https://doi.org/10.1200/JCO-25-01204

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SOURCE US WorldMeds