Moleculin Biotech, Inc. (Nasdaq: MBRX) announced that the World Health Organization (WHO) has approved "naxtarubicin" as the international non-proprietary name for its investigational cancer drug Annamycin. This designation represents a significant milestone in the drug's development pathway and potential future commercialization.
The approval comes from the International Nonproprietary Names (INN) Expert Committee of the WHO, following a rigorous evaluation process that ensures the name adheres to nomenclature guidelines and is free from potential conflicts. With this INN now established, alongside prior approval by the United States Adopted Names (USAN), Moleculin has secured a universally recognized generic name for its lead drug candidate.
"The assignment of the non-proprietary name represents an important step in the development and potential future commercialization of Annamycin," said Walter Klemp, Chairman and CEO of Moleculin. "With this INN now given and prior approval by the United States Adopted Names (USAN), we have the ability to establish a universally recognized and conflict-free nonproprietary drug name for Annamycin."
Advancing the MIRACLE Trial
Annamycin, now to be known generically as naxtarubicin, is currently being evaluated in combination with cytarabine (together referred to as AnnAraC) in the pivotal, adaptive design Phase 3 MIRACLE trial for the treatment of relapsed or refractory acute myeloid leukemia (AML). This global trial, which derives its name from "Moleculin R/R AML AnnAraC Clinical Evaluation," includes sites across the United States, Europe, and the Middle East.
Patient dosing has commenced, and the company expects an initial data readout in the second half of 2025. The trial follows a successful Phase 1B/2 study (MB-106), which the company believes has substantially de-risked the development pathway toward potential approval.
Unique Therapeutic Profile
Annamycin is positioned as a next-generation anthracycline designed to overcome two major limitations of currently prescribed anthracyclines: multidrug resistance and cardiotoxicity. The drug utilizes a unique lipid-based delivery technology and has shown potential for treating a wide range of cancers beyond its current development focus.
Preclinical studies performed at a world-renowned cancer center indicate Annamycin may have potential applications in numerous cancer types beyond AML and soft tissue sarcoma lung metastases, its current development targets.
Regulatory Designations
The drug has received multiple regulatory designations that could accelerate its path to market:
- Fast Track Status from the FDA for relapsed or refractory AML
- Orphan Drug Designation from the FDA for both relapsed or refractory AML and soft tissue sarcoma
- Orphan Drug Designation from the European Medicines Agency (EMA) for relapsed or refractory AML
These designations provide various benefits, including more frequent FDA interactions, potential eligibility for accelerated approval and priority review, and extended market exclusivity upon approval.
Strengthened Intellectual Property Portfolio
In parallel with the WHO naming approval, Moleculin has significantly bolstered Annamycin's intellectual property protection with two new U.S. patents:
- U.S. patent number 12,257,261: "Preparation of Preliposomal Annamycin Lyophilizate," covering methods of making liposomal Annamycin
- U.S. patent 12,257,262: "Method of Reconstituting Liposomal Annamycin," covering methods of making liposomal Annamycin suspension
Both patents extend protection until June 2040, subject to potential adjustments and extensions. These additions bring Moleculin's Annamycin-related U.S. patent portfolio to four, complementing existing European patents.
"We remain focused on expanding our intellectual property portfolio for Annamycin," said Klemp. "Following the issuance of two U.S. patents in 2024, these new patents enhance the exclusivity of Annamycin, bringing to four the total number of U.S. patents related to Annamycin, in addition to the European patents granted."
Company Background
Moleculin Biotech is a Phase 3 clinical-stage pharmaceutical company developing a pipeline of therapeutic candidates for hard-to-treat tumors and viral infections. Beyond Annamycin, the company's portfolio includes WP1066, an Immune/Transcription Modulator targeting brain tumors, pancreatic and other cancers, and WP1122, an antimetabolite being developed for pathogenic viruses and certain cancer indications.
As Moleculin transitions to using the name naxtarubicin in the near term, the company continues to focus on advancing its lead program through clinical development while maintaining a strong intellectual property position that could support commercial exclusivity well into the next decade.
The company will require additional financing to complete its clinical development plans, with the timeline for the MIRACLE trial data readout contingent on securing timely funding.
