Polivy (polatuzumab vedotin) is a cutting-edge therapeutic drug used to treat certain types of lymphoma, particularly diffuse large B-cell lymphoma (DLBCL). This medicinal product is supplied for injection: 30 mg or 140 mg of polatuzumab vedotin-piiq as a lyophilized powder in a single-dose vial. To know how Polivy works, let’s straightforwardly understand its mechanism of action.
Targeting Cancer Cells:
Polivy is designed to target cancer cells with precision. It’s an antibody-drug conjugate, which means it combines two powerful components: a monoclonal antibody and a cytotoxic drug. The monoclonal antibody part of Polivy is engineered to recognize and bind to a specific protein found on the surface of B-cells, called CD79b. This protein is often present in large amounts on the surface of cancerous B-cells in DLBCL.
Delivery System: Monoclonal Antibody
Once Polivy is administered, the monoclonal antibody seeks out and attaches itself to the CD79b protein on the cancerous B-cells. This targeting is crucial because it ensures that the drug is delivered directly to the cancer cells, minimizing the impact on healthy cells. Think of the monoclonal antibody as a homing device that guides the drug to the right destination.
The Cytotoxic Payload:
Attached to the monoclonal antibody is a cytotoxic drug called monomethyl auristatin E (MMAE). This drug is highly potent and capable of killing cells. However, on its own, MMAE is too toxic to be used safely. By linking it to the antibody, Polivy ensures that MMAE is delivered directly to the cancer cells, sparing most healthy cells from its toxic effects.
Internalization and Cell Death:
When Polivy binds to the CD79b protein on the surface of a cancer cell, it is taken into the cell through a process called internalization. Once inside, the acidic environment of the cell breaks the bond between the antibody and the cytotoxic drug. This releases MMAE inside the cancer cell, where it can do its work.
MMAE interferes with a critical part of the cell’s machinery called the microtubules. Microtubules are essential for cell division, and by disrupting them, MMAE prevents the cancer cells from dividing and multiplying. Without the ability to divide, the cancer cells eventually die.
Minimal Impact on Healthy Cells:
One of the significant advantages of Polivy is its targeted approach. Because it delivers the cytotoxic drug specifically to cancer cells, it tends to have fewer side effects compared to traditional chemotherapy, which can affect both cancerous and healthy cells indiscriminately. This targeting helps to reduce the collateral damage to healthy tissues, which is a common issue with conventional cancer treatments.
Conclusion:
In summary, Polivy’s mechanism of action involves a sophisticated delivery system that targets CD79b proteins on cancerous B-cells. It uses a monoclonal antibody to deliver a potent cytotoxic drug directly to these cells, thereby killing them while sparing most healthy cells. This targeted approach makes Polivy a powerful tool in the fight against diffuse large B-cell lymphoma, offering hope for better outcomes with fewer side effects.
