Cergutuzumab amunaleukin is a recombinant fusion protein that Roche is developing as a treatment for advanced solid tumors or ones that have spread to other parts of the body. A fusion protein is made up of parts of two or more proteins.
How cergutuzumab amunaleukin works
Cergutuzumab amunaleukin consists of an engineered form of the protein interleukin-2, or IL-2v, fused to a human monoclonal antibody. A monoclonal antibody is a manmade antibody that mimics one that the immune system generates to fight invaders.
Cergutuzumab amunaleukin targets carcinoembryonic antigen, or CEA, a protein produced in very small amounts after birth but found at high levels on the surface of several types of tumor cells.
Interleukin-2 is a cell signaling molecule that plays an essential role in immune response. It is mainly produced by some types of T-cells. It stimulates an immune response against cancer by increasing the growth and activity of other T-cells and immune B-cells.
When IL-2 binds to its receptor, IL-2R, it activates another type of immune cell called regulatory T-cells, or Tregs. Tregs actually dampen immune response. The interaction between IL2 and IL-2R reduces the activity of cell-killing T-cells to the point that they are no longer able to target cancer cells. The engineered form of IL-2 in cergutuzumab amunaleukin — known as IL-2v — is unable to bind to IL-2R, which means it does not activate Tregs.
By coupling IL-2v with an antibody against CEA, cergutuzumab amunaleukin triggers a T-cell response against cancer cells with CEA.
Cergutuzumab amunaleukin in clinical trials
Roche conducted a Phase 1 clinical trial to evaluate the safety and effectiveness of increasing doses of cergutuzumab amunaleukin in patients with advanced solid tumors or cancer that had spread. The trial also looked at the therapy’s pharmacokinetics, or how it moved inside the body.
Preliminary data on 11 patients published in 2015 showed that cergutuzumab amunaleukin was able to target specific tumor cells and increase the immune system’s response against them. The study was completed in 2016 but Roche has not published additional findings on it.
The company is also evaluating a combination of cergutuzumab amunaleukin and another of its cancer therapies, Tecentriq (atezolizumab), in a Phase 1b trial (NCT02350673). It is investigating the combo’s safety, pharmacokinetics, and anti-tumor activity. Trial participants have either advanced solid tumors or cancer with CEA that has spread to other parts of the body. In addition, the patients’ cancer has either progressed or they have been unable to tolerate standard treatments.
The study has two parts. In stage 1, participants receive escalating doses of cergutuzumab amunaleukin and fixed doses of Tecentriq so researchers can determine a recommended treatment dose. In stage 2, the research team evaluates the dose of cergutuzumab amunaleukin that they recommended, combination with Tecentriq, for 24 months.
Roche continues to enroll participants for the trial in the United States, Canada, Denmark, the Netherlands, Spain, and Switzerland.
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