US-based specialty pharmaceutical company US WorldMeds Ventures LLC announced on Tuesday a definitive merger agreement under which it has acquired Orbus Therapeutics Inc, a privately held pharmaceutical company developing investigational eflornithine for rare and serious brain tumours.

This transaction adds Orbus' late-stage programme 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 United States. 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 the FDA granted the programme Breakthrough Therapy designation for the treatment of anaplastic astrocytoma.

US WorldMeds currently commercialises 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 company said.