Race Oncology has uncovered that its anticancer drug bisantrene exists as three light-sensitive isomers, with only one showing potent activity. The company has filed patents to protect this active form, potentially extending its intellectual property rights until 2045.
- Discovery of three photoisomers in bisantrene with distinct anticancer activities
- Only the (E,E)-bisantrene isomer exhibits significant therapeutic effect
- Three new patent applications filed covering composition, manufacture, and use
- Potential 20-year composition of matter patent protection until 2045
- Enhanced commercial prospects for Race’s RC110 and RC220 drug formulations
Breakthrough Discovery in Bisantrene Chemistry
Race Oncology has announced a significant scientific advancement in understanding its lead anticancer agent, bisantrene. The company’s researchers found that bisantrene is not a single compound but a mixture of three photoisomers; molecules that differ in the spatial arrangement of atoms and interconvert upon exposure to visible light. Crucially, only the (E,E)-bisantrene isomer, also known as the "all-trans" form, demonstrates meaningful anticancer activity.
Strategic Patent Filings to Protect Active Isomer
Building on this insight, Race Oncology has developed manufacturing and formulation processes to isolate and deliver the pure (E,E)-bisantrene isomer to patients. On 12 September 2025, the company filed three patent applications covering the chemical composition, production methods, and therapeutic uses of this active isomer. If granted, these patents would provide robust composition of matter intellectual property protection for 20 years, potentially extending to 2045 with patent term extensions in key markets such as the United States.
Implications for Clinical Development and Commercialisation
This new intellectual property position fundamentally enhances Race Oncology’s commercial prospects. Composition of matter patents are the gold standard in pharmaceutical IP, offering exclusivity that covers the active drug itself regardless of formulation or use. This exclusivity is critical for attracting pharmaceutical partners and investors, who typically seek at least 8 to 10 years of patent life at product launch to justify development costs.
Race’s CEO, Dr Daniel Tillett, emphasised the transformative nature of this discovery, noting it "fundamentally changes the commercial prospects of Race Oncology" by securing the strongest possible IP protection for their RC110 and RC220 formulations. These formulations, which have already demonstrated clinical activity in acute myeloid leukemia and solid tumors, now stand on a firmer legal and commercial foundation.
Revisiting Historical Data and Future Outlook
The discovery also sheds light on why earlier clinical trials from the 1980s, conducted with a mixed isomer formulation, showed variable results. The rapid light-induced interconversion of isomers likely led to inconsistent dosing of the active (E,E) form. Race’s purified isomer approach aims to reduce such variability, potentially improving efficacy and safety profiles.
Looking ahead, Race Oncology is accelerating patent examination to support ongoing pharmaceutical partnering discussions and is preparing for pivotal Phase 3 trials. The company will host a webinar on 18 September 2025 to discuss the discovery’s significance and its impact on Race’s clinical and commercial strategy.
Bottom Line?
Race Oncology’s patent filings could redefine its market value and accelerate partnerships, but patent approval and clinical success remain key hurdles.
Questions in the middle?
- Will the patent offices grant the composition of matter patents without opposition?
- How will pharmaceutical partners respond to the strengthened IP position?
- What timelines and resources will Race allocate to advance Phase 3 trials for RC110 and RC220?