Anti-cancer Drug, Sutent

Sutent (sunitinib) is noted as the first drug to be approved on the same day by the FDA for the treatment of two different diseases. Sunitinib was approved on January 26, 2006 for the treatment of rare gastrointestinal stromal tumors (GIST) and renal cell carcinomas (RCC). The drug differs in the way in which it treats each disease. In GIST it slows down the tumor's growth and in RCC it decreases the tumor's size.

Gastrointestinal stromal tumors are rare tumors and derive from interstitial cells of the autonomic nervous system called Cajal. The autonomic nervous system regulates your intestinal tract, heart rate and blood pressure. As a result, these tumors can occur anywhere along the gastrointestinal tract (esophagus to rectum) since it's autonomically innervated. But, most commonly it has been found to affect the stomach. Gastrointestinal stromal tumors have a genetic mutation that is responsive to specific drugs like Sutent.

The drug can also be used to treat RCC. Renal cell carcinoma is responsible for the majority of kidney cancer. Although researchers have not been able to target a cause for the development of RCC certain risk factors have been attributed to it. Some factors include hypertension, dialysis, radiation or hereditary diseases (e.g., von Hippel Lindau).

In GIST patients the drug, a product of Pfizer, is indicated for patients who do not respond well to Gleevec. Sutent works by tyrosine-kinase inhibition which blocks cellular communication and growth. This drug class has been used to prevent tumor growth and the treatment of cancer. Gleevec (imatinib) and Sprycel (dasatinib) also belong to this drug class. While Sutent provides advancement in the treatment of this rare stomach cancer it has been shown to cause heart problems.

Most drugs are used to treat one disease yet, cause other side effects and Sutent is no exception. Some of the other reported side effects were diarrhea, taste changes, weakness and fatigue. However, hypertension in patients taking Sutent has been the focus of recent studies. One such study was published in the Lancet. The study was a collaborative effort led by Dr. Chen an assistant professor at Harvard Medical School. The medical records of 75 patients receiving Sutent were evaluated for the development of certain cardiovascular problems. These patients exhibited Gleevec-resistance to GIST and experienced cardiac problems such as myocardial infarction, hypertension and congestive heart failure. Most of these heart issues could be managed medically but, most of the patients affected had a preexisting history of coronary artery disease. So, patients without any previous history of heart disease were less likely to develop cardiovascular problems.

In a different study, published in the New England Journal of Medicine increases in blood pressure was also noted in metastatic RCC patients taking Sunitinib. In this study principal investigator, Dr. Azizi noted that home blood pressure monitoring via teletransmission revealed marked HTN. These blood pressure changes were otherwise missed during routine office visits.

Pfizer released a statement acknowledging the cardiac problems associated with the drug based on these findings. However, the pharmaceutical giant noted that the cardiac risks can be managed as well. The company mentioned that in follow-up studies lower incidences of heart problems occurred in both patient populations.

Sutent is lifesaving for patients with GIST and RCC. So, physicians prescribing the drug need to assess their patients for signs indicative of developing heart problems such as shortness of breath, weakness and swelling. Dr. Chen noted that these signs are nonspecific and can be attributed to cancer as well in these patients which can result in missed diagnosis for emerging cardiovascular disease in those taking Sutent.

Sources: "Sutent Linked with Heart Problems," Cancer Consultants, "New Cancer Drug Tied to Heart Problems," Forbes, Michel Azizi, M.D., Ph.D., Antoine Chedid, M.D., and Stéphane Oudard, M.D., Ph.D. "Home Blood-Pressure Monitoring in Patients Receiving Sunitinib." New England Journal of Medicine 358.1 (2008): 95-97