A new study reveals why PARP inhibitors—targeted drugs used in ovarian cancer—work well for some patients but fail in others. Using advanced imaging of live human tumor samples, researchers found that the key difference lies in how these drugs spread and behave inside individual cancer cells.
The study shows that some PARP inhibitors, such as rucaparib and niraparib, become trapped inside lysosomes, the cell’s recycling compartments. These structures act like storage reservoirs, slowly releasing the drug over time. As a result, drug distribution within tumors becomes uneven, with some areas receiving high exposure while others get very little, which may reduce overall effectiveness.
In contrast, olaparib does not accumulate in lysosomes, suggesting that different PARP inhibitors move through tumor tissue in distinct ways. This discovery highlights that drug behavior at the cellular level plays a major role in treatment success.
Researchers say these findings could help guide more personalized cancer treatment by identifying how specific drugs distribute within tumors, potentially overcoming resistance and improving outcomes for patients with ovarian, breast, and prostate cancers.