OrbiMed, Varian lead $105M round for targeted radiotherapy outfit Fusion Pharma

Two years after Fusion Pharmaceuticals raised a modest $25 million series A, the targeted radiotherapy player has reeled in $105 million in new capital to push a clinical-stage program and build a pipeline of new treatments and combination therapies. 

Fusion’s founding venture investor, Johnson & Johnson Innovation, joined OrbiMed and Varian in the financing with Perceptive Advisors, Pivotal bioVenture Partners, Rock Springs Capital and other existing backers also pitching in. 

Fusion’s targeted approach combines alpha particle-emitting radiotherapeutics with molecules that deliver them to tumors. Using a molecule such as an antibody to avoid delivering radiation indiscriminately and harming healthy cells is not a new idea. But the company believes that its linker technology—which connects a molecule to a radioactive compound—can clear radiotherapeutics more quickly than commercially available linkers, thereby extending their therapeutic window. 

The company's lead asset, known as FPI-1434, is currently being tested in advanced solid tumors in a 30-patient phase 1 study. It combines an antibody targeting the cancer biomarker IGF-1R and a radioactive isotope of actinium that has shown promise in treating prostate cancer. Though this treatment uses an antibody, the linker technology can be applied to other targeting compounds, such as small molecules. 

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Fusion has a handful of preclinical programs behind FPI-1434 and plans to build its pipeline through internal discovery, in-licensing targeting molecules and striking up new partnerships, the company said in a statement. 

“The investment positions us to implement our clinical and partnering strategies around [225Ac]-FPI-1434, expand our team and fully exploit the unique advantages of our linker technology,” said Fusion CEO John Valliant, Ph.D., in the statement. 

Though targeted radiotherapy has been around for decades without stirring up the excitement surrounding other classes of cancer drugs, the field may just be heating up. Novartis at least seems to think so; in the span of one year, the Big Pharma inked two acquisitions totaling $6 billion to get its hands on radiotherapies from Advanced Accelerator Applications and Endocyte that use small molecules to zero in on cancer cells.