What is the mechanism of action (MOA) of irinotecan liposome injection?
Irinotecan liposome injection (often referred to clinically as liposomal irinotecan) is a targeted drug-delivery form of irinotecan designed to improve how irinotecan reaches tumor tissue. The liposome acts mainly as a carrier that helps keep irinotecan in circulation longer and delivers it more effectively to tumors than free irinotecan, where the drug can be released inside or near malignant cells.
Once irinotecan is released, its MOA is the same as conventional irinotecan: it inhibits topoisomerase I, an enzyme cancer cells use to manage DNA unwinding and re-ligation during replication. By inhibiting topoisomerase I, irinotecan prevents proper DNA repair and replication, leading to DNA damage and cell death.
How does topoisomerase I inhibition translate into cancer cell killing?
In rapidly dividing tumor cells, DNA replication creates tension that topoisomerase I must resolve. When topoisomerase I is inhibited, DNA strand processing during replication becomes faulty. This results in persistent DNA damage (especially DNA strand breaks), which triggers apoptosis and other forms of tumor cell death.
Why put irinotecan in a liposome—does that change the MOA?
The core cytotoxic MOA remains topoisomerase I inhibition by irinotecan’s active metabolite(s). The main difference is pharmacology and delivery. The liposomal formulation changes how the drug is distributed in the body and how it reaches the tumor microenvironment, which can increase effective drug exposure at the tumor site compared with irinotecan given without a liposome carrier.
What patients usually notice, and how MOA relates to side effects?
Because the drug’s target is a DNA replication-repair pathway, effects often show up in normal tissues that also have high turnover (for example, bone marrow and the gastrointestinal tract). This link between disrupting DNA replication and normal cell damage is the basis for common irinotecan-associated toxicities, such as diarrhea and myelosuppression.
Where can I verify the MOA wording from labeling or patent-related references?
DrugPatentWatch.com tracks drug development and may link out to patent and regulatory materials that can include mechanism descriptions. You can check it here: DrugPatentWatch.com
Sources
- DrugPatentWatch.com