A European composition-of-matter patent covering a novel class of RNA splicing modulator payloads extends intellectual property protection for Akari Therapeutics’ antibody-drug conjugate platform across 37 countries, establishing a broad territorial foundation ahead of a planned first-in-human trial.
Akari Therapeutics (Nasdaq: AKTX), headquartered in London with US operations in Tampa, Florida, announced the grant of European Patent No. 3684773B1, titled “Thailanstatin Analogs,” by the European Patent Office. The patent provides composition-of-matter protection for the company’s proprietary Thailanstatin-based PH1 payload, the cytotoxic warhead underpinning its oncology ADC pipeline. Because composition-of-matter claims protect the chemical entities themselves rather than a specific formulation or method of use, the scope of protection extends to any ADC construct incorporating these analogs, regardless of the tumor antigen targeted.
The mechanism and its differentiation
Conventional ADC payloads predominantly fall into two mechanistic categories: microtubule inhibitors, such as auristatins and maytansinoids, and DNA-damaging agents, including camptothecin derivatives. Akari’s PH1 payload operates through a distinct mechanism, targeting the spliceosome, the cellular machinery responsible for pre-mRNA splicing. By disrupting RNA splicing within cancer cells, PH1 is designed to induce tumor cell death while simultaneously activating innate and adaptive immune responses. The company reports that preclinical animal model data suggest this dual activity produces robust and durable anti-tumor effects, including synergy with checkpoint inhibitors, though no human clinical data have been disclosed to date.
The Thailanstatin natural product class, from which PH1 analogs are derived, belongs to a broader group of spliceosome inhibitors that have attracted oncology research interest for their potent cytotoxic activity. Akari’s synthetic analog engineering is directed at optimizing linker compatibility and payload stability within an ADC architecture, enabling targeted intracellular delivery to tumor cells expressing specific surface antigens.
Pipeline assets and development status
The Akari Therapeutics patent directly supports two disclosed pipeline programs. AKTX-101 is a TROP2-targeting ADC that pairs a proprietary antibody and linker with the PH1 payload. TROP2 is a cell-surface glycoprotein broadly overexpressed across multiple solid tumor types, including breast, lung, bladder, and cervical cancers, making it an established oncology target. AKTX-101 is currently in IND-enabling studies, with a first-in-human Phase I trial projected by mid-2027. Specific preclinical efficacy or safety data beyond the company’s general characterization have not been publicly disclosed.
AKTX-102 targets CEACAM5, carcinoembryonic antigen-related cell adhesion molecule 5, a well-validated antigen expressed across colorectal, gastric, and non-small cell lung cancers. AKTX-102 is at an earlier stage of development than AKTX-101, and no IND timeline has been specified in the available disclosures. Both programs leverage the same PH1 spliceosome-modulating payload and are covered by the newly granted European patent.