Blood pressure drug could increase potency of chemotherapy

A tested blood pressure drug could be used to increase the effectiveness of chemotherapy in cancer patients, revealed a new US study. Scientists from Massachusetts General Hospital (MGH) have found that losartan, a drug currently used for the treatment of high blood pressure, showed effectiveness in allowing more chemotherapy reach a cancer by opening up blood vessels. 

Testing on mice, the researchers found that more chemotherapy was allowed to reach cancerous tumours when they were also being treated with the blood pressure medicine. Losartan is from the class of drugs called angiotensin inhibitors, which have been used to treat patients with high blood pressure for a number of years. 

Taking blood pressure medicine without a cancer treatment can help a tumour to grow as it increases blood flow. However, using a certain class of blood pressure medicine alongside chemotherapy treatment could help to fight the tumour more successfully, as the treatment, whether chemotherapy, immunotherapy or radiation, is able to penetrate deeper into the tumour. Ultimately this can lead to the tumour shrinking faster than it would when targeted with the cancer treatment alone.

The class of drugs that losartan belongs to also reacts differently with tumours in comparison to anti-angiogenesis blood pressure drugs. Doctor Rakesh Jain, senior author of the study, explained: "Unlike anti-angiogenesis drugs, which improve tumour blood flow by repairing the abnormal structure of tumour blood vessels, angiotensin inhibitors open up those vessels by releasing physical forces that are applied to tumour blood vessels when the gel-like matrix surrounding them expands with tumour growth."

By testing on mice, scientists were able to discover that losartan was able to increase the distribution of nanomedicines, relatively large molecules of cancer treatment. This distribution was enabled by the blocking of collagen formation. Losartan was also found to inhibit the formation of hyaluronan, which, alongside collagen, causes compression of blood vessels in tumours. This allowed more of the chemotherapy to reach the tumour.

A clinical trial has now been launched to assess whether the drug can aid in the treatment of pancreatic cancer.