The Science Behind


How It Works

Targeted Alpha


Fusion is utilizing the advantages of alpha medical isotopes to develop targeted alpha therapies. We use targeting molecules, such as antibodies, armed with potent alpha emitting medical isotopes to precisely and effectively induce cancer cell death. Since alpha particles travel only a short distance, they localize the radiation to the tumor.

Comparative Chart
Targeting Molecule
Fast-Clear™ Linker
Chelate / Manufacturing



Fusion’s TAT platform and product candidates, if approved, could provide several potential advantages over currently available radiopharmaceuticals, including:

  • enhanced tumor-killing power by using alpha particle radiation;
  • ability to use multiple targets and classes of targeting molecules;
  • broad applicability across multiple tumor types;
  • increased tolerability and therapeutic window associated with our Fast-Clear linker;
  • exploitation of multiple mechanisms of action, including direct DNA damage and an alpha particle mediated enhanced anti-tumor immune response;
  • an established manufacturing process and supply chain; and
  • ability to use imaging diagnostics to enrich our targeted patient populations.

The multiple mechanisms of action of Fusion’s TATs may give them the ability to treat hard-to-treat solid tumors and the potential to work synergistically with other approved oncology therapies. 

  • The primary mechanism of action of 225Ac is direct cell damage through the induction of multiple double-stranded DNA breaks. 
  • A secondary mechanism, which would likely expand the effective direct cell kill range of the alpha particles, is referred to as the Bystander Effect. This effect has been shown to be as significant to the overall efficacy in killing cancer cells as the direct DNA breaks. 
  • A third potential mechanism of action results from the destruction of tumor cells through alpha radiation. In preclinical studies, destroyed tumor cells released tumor-associated antigens which activated T cells at tumor sites.

We believe that our Fast-Clear™ linker technology promotes a wider therapeutic window with a potentially safer and more effective therapy than currently available options.

Fusion’s proprietary Fast-Clear™ linker technology promotes the rapid excretion of medical isotopes that are not specifically bound to cancer cells. The Fast-Clear™ linker technology (the “connector” between a molecule and a medical isotope) is engineered to clear more medical isotopes at a faster rate, compared to commercial technologies to expand the therapeutic window. Fusion has a library of proprietary linkers that can optimize the excretion route and kinetics for different targeting molecules.

Given the power and versatility of the Fast-Clear™ linker technology, Fusion is applying this technology to a range of molecules and molecule classes (antibodies, small molecules, and others).

In addition, we believe the Fusion advantage over currently available radiopharmaceuticals, includes: 

  • Enhanced tumor-killing power through alpha particle radiation.
  • Ability to use multiple targets and classes of targeting molecules.
  • Broad applicability across multiple tumor types.
  • Established manufacturing process and supply chain.
  • Ability to use imaging diagnostics to enrich our targeted patient populations.

Contact us to learn more about Fusion’s Fast-Clear™ linker technology and partnering opportunities.

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