Thrombopoietin

Definition

Thrombopoietin is an investigational or experimental drug that may increase the number of platelets in the bloodstream.

Purpose

Thrombopoietin is an experimental drug that may be used to treat thrombocytopenia (a reduced number of platelets in the blood).

Description

Thrombocytopenia, or a low number of platelets in the blood, can be a life-threatening condition. Platelets are necessary for the normal process of blood clotting. When someone experiences thrombocytopenia, a cut or bruise might not heal quickly, or at all, without medical intervention. Therefore, patients with a low platelet cell count must take special precautions, and suffer significant risk.

Thrombocytopenia is a common side effect from many common chemotherapy agents. These agents temporarily decrease the production of platelets, as well as white blood cells that fight infection and red blood cells that carry oxygen. Carboplatin is an example of an agent that has a tendency to lower platelet counts. Like other cells of the blood (white blood cells and red blood cells), the number of platelets will generally increase and return to normal over days and weeks following the administration of chemotherapy.

By reducing the severity of platelet-related side effects, thrombopoietin could allow the antitumor medication to be used at higher doses and/or for longer periods of time. Thrombopoietin may also be used in other situations in which patients have low platelet cell counts.

Thrombopoietin is derived from the gene of the same name. A laboratory-synthesized version of the human gene product encourages the development of platelet cells from precursor cells in the blood.

Thrombopoietin is an investigational, or an experimental, drug in the U.S. This means that the FDA has not approved this drug for general use as of mid-2001. Generally, investigational drugs are made available through participation in clinical trials .

Recommended dosage, precautions, side effects, and interactions

As noted above, investigational drugs generally are prescribed as part of a clinical trial. Clinical trials seek to determine how effective a drug is at treating the targeted condition, the effective dose of the drug, any precautions patients should take before the drug is administered, any side effects the drug may have, and any interactions the investigational drug may have with other drugs. Since thrombopoietin is investigational, it is premature to discuss dosage, precautions, side effects, and interactions.

Michael Zuck, Ph.D.

KEY TERMS

Investigational drug

—A drug that has not been approved for marketing by the FDA. These drugs are generally available to patients through participation in clinical trials/research studies.

Thrombocytopenia

—A condition characterized by a reduced number of platelets in the blood.