BUILDING THE BACKBONE
Mersana’s approach to building novel drug conjugates starts with our Fleximer polymer, which can dramatically improve drug solubility and pharmacokinetics, reduce immunogenicity and optimize drug load. Our Fleximer polymer is uniquely biodegradable, well tolerated with a favorable safety profile and has been clinically validated. The Fleximer polymer serves as the backbone for our drug conjugates. We customize the size of the backbone based on the type and quantity of therapeutic payloads, as well as the nature of the targeting protein being attached.
We determine which and how many linkers to use to attach the payload to the backbone. Mersana’s diverse array of linker chemistries allows us to arm our drug conjugates with significantly higher loads of anti-cancer agents than conventional ADC technologies, as well as to potentially arm a single immunoconjugate with a combination of payloads. The custom-designed linkers allow us to control the rate, mechanism and localization of drug release, potentially increasing efficacy and minimizing off-target side effects.
Using a chemically distinct linker from those used to attach the therapeutic payload, we then attach an antibody, or alternative targeting moiety such as an antibody fragment, to the backbone. The ability to attach a variety of targeting agents to the Fleximer backbone allows us to choose the one that will most effectively reach, bind to and penetrate the tumor cell, while sparing healthy cells. By using separate linker chemistries to attach the targeting agent and drug payload, we can choose the best linkers for each task.
MAXIMIZING THERAPEUTIC BENEFIT
While in the bloodstream, our Fleximer polymer protects the drug payload, ensuring stability. Through optimized design and careful control of numerous parameters, our immunoconjugates are preferentially taken up by cancer cells, accumulating and persisting in the tumors to deliver a prolonged therapeutic effect. Once the drug payload has been released, the Fleximer polymer and linkers biodegrade into safe byproducts, further supporting the potential safety benefits of this novel approach.