Insulin Potentiation Therapy
Questions from the Clinic:
How effective is insulin potentiation therapy (IPT) in treating and preventing cancer? Is it a better alternative to standard chemotherapy? How exactly does it work?
Figure 1: Insulin potentiated therapy (IPT) entails the administration of insulin with chemotherapy drugs. Proponents of IPT theorize that insulin increases cell permeability to cancer fighting drugs, which means it can lower the doses of chemotherapy needed to fight cancer. Image courtesy of Memorial Sloan Kettering Cancer Center.
Insulin potentiation therapy, often stylized as IPT, is an alternative cancer therapy that uses insulin as an adjuvant to chemotherapy drugs. First developed by Dr. Donato Perez Garcia in the 1930s, IPT is believed by its proponents to minimize the negative side effects associated with chemotherapy drugs by using much lower doses in the 20% to 40% range, and augmenting with the insulin bolus, without reducing the efficacy of treatment.(1) Treatment strategies capable of improving the tolerability of cancer drugs are highly desirable, as many approved cytostatic drugs have relatively low tumor specificity and high toxicity. Alternative medications, like immune checkpoint inhibitors, can cause even more severe side effects than other conventional immunotherapies and require early recognition and intervention to safeguard patients.(2) Using lower doses to reduce common side effects while maintaining equal effectiveness by insulin potentiation sounds like a perfect scenario and thus fosters the curiosity around this option.(5)
II. Mechanism of Action
Substantial evidence indicates that the insulin receptor and its related signaling pathways are implicated in the development and progression of various cancers.(3,4) Relative to healthy cells, cancer cells express a greater number of insulin receptors. Proponents of IPT believe that this difference in insulin receptor density makes malignant cells more permeable to chemotherapy drugs in the presence of insulin. As a result, only a fraction of the normal dose of chemotherapy is required to achieve an antitumoral effect. By using lower doses of cancer drugs, clinicians can help limit side effects to healthy cells from therapy. In one breast cancer cell line (MCF-7), scientists have noted that insulin increases in vitro methotrexate uptake while simultaneously increasing its cytotoxicity. That said, it appears that the mechanism responsible for methotrexate’s increased cy