Axplora has completed its initial R&D batches of Exatecan as it moves forward with Axotecan, an initiative designed to establish an independent European supply source for the highly potent payload used in a growing number of antibody-drug conjugate (ADC) programs. The initiative is intended to give ADC developers an additional source of Exatecan while also connecting payload production with Axplora’s existing payload-linker and ADC development and manufacturing capabilities.

The company has produced gram-scale quantities of the material and is targeting validation batches by the end of 2026. Registration activities are planned for 2027, with initial GMP supply expected in late 2027, subject to the completion of technical, quality and regulatory requirements.

Exatecan is a potent topoisomerase I inhibitor that has become an important starting material for ADC payload development. As more Exatecan-based candidates move through clinical development, manufacturers face increasing requirements for dependable access to material with consistent quality, appropriate scale and predictable delivery schedules.

Axplora said Axotecan was developed in response to those requirements, with the aim of adding sourcing diversity to the Exatecan supply chain and simplifying the transition from payload production to subsequent payload-linker and ADC manufacturing steps. Rather than separating these activities across multiple suppliers, Axplora intends to connect them through its European manufacturing network. The company expects the approach to reduce technical handoffs and give developers greater visibility when planning development, scale-up and eventual commercial supply.

The project is part of Axplora’s broader Partnership in Motion strategy, which emphasizes collaboration between its businesses and closer engagement with customers as new manufacturing requirements emerge. Axotecan brings together capabilities from two Axplora businesses: Farmabios and Novasep CDMO. Farmabios will contribute its experience in highly potent active pharmaceutical ingredients (HPAPIs), including development, containment and manufacturing at its Gropello Cairoli site in Italy. Novasep CDMO will provide its expertise in payload-linker development and manufacturing and bioconjugation at Axplora’s ADC center of excellence in Le Mans, France.

Axplora has more than 35 years of experience in high-potency synthesis and purification. Its Gropello Cairoli facility operates five independent manufacturing lines under an OEB 5 containment strategy and can accommodate batch sizes ranging from 0.5 kg to 300 kg. The company says this infrastructure provides a pathway for Axotecan to progress from development-scale quantities toward larger-scale production as customer requirements increase.

At Le Mans, payload-linker development and manufacturing are co-located with bioconjugation activities. Linking these capabilities with Exatecan production is intended to create a more continuous manufacturing pathway from payload starting material through to ADC drug substance.

For ADC developers, the model could also allow decisions made during Exatecan synthesis and purification to be considered alongside downstream conjugation requirements. Axplora expects this to support technical transfers, scale-up planning and continuity as programs move toward commercial manufacturing.

Axplora said it has been consulting with ADC developers during the development of Axotecan to better understand expected specifications, volumes and potential integration requirements ahead of GMP availability. “Partnership starts with listening carefully to customers and understanding not only what they need today, but what could constrain their progress tomorrow,” says Martin Meeson, CEO of Axplora. “With Axotecan, we are turning that insight into action. We are moving early to create an independent European supply option while continuing to work with ADC developers to ensure it meets their requirements. That is what Partnership in Motion means in practice: investing with purpose, shaping the solution with customers and helping important new medicines progress toward patients with greater confidence.”

The first R&D batches have now been completed. Validation batches are planned for before the end of 2026, followed by registration activities during 2027 and a targeted initial GMP supply date in late 2027, pending successful completion of the necessary technical, quality and regulatory milestones.

For more information, visit www.axplora.com.