In order to gain approval for any new drug, it must undergo years of testing and clinical trials. The newest drug to treat mesothelioma , Onconase (ranpirnase), proved to be no different in this requirement. Onconase is a drug created by the pharmaceutical company Alfacell. It has been derived from the egg cells of Northern Leopard Frogs (Rana pipiens), and in the experiments done using the drugs on tumors, it seems to have an effect on halting their growth. The last stage of clinical trials before approval, Phase III, showed that this drug proved to be effective in patients with malignant mesothelioma whose cancer failed to be slowed by chemotherapy. Scientists wanted to know why Onconase seemed to work better than other treatments in these patients.
Many possibilities for Onconase’s effectiveness were tested in a study whose results were recently published in Cell Cycle. It seemed that the drug had an anti-tumor property and worked by targeting the small interfering RNA (siRNA). RNA forms play an integral role in gene and cell replication, which runs out of control in tumors. By slowing or stopping the cell replication of tumors, cancers can be halted in their progression. In the study, by honing in on siRNA, Onconase was able to prevent the quelling of a common gene –glyceraldehyde 3-phosphate dehydrogenase (GAPDH). This led the scientists to conclude that Onconase would indeed by effective in controlling the siRNA agent during tumor cell replication and growth. This study further enforces the studies behind the clinical trials which led to Onconase’s approval.