ESAs Increase Blood Clot Risk

Drugs to treat anemia in older cancer patients increased their risk of blood clots and didn’t reduce the need for blood transfusions.

Among over 56,000 cancer patients 65 and older treated in community settings from 1991 through 2002, 27 percent received an erythropoiesis-stimulating agent (ESA).   Fifteen percent of those who got ESAs developed a blood clot (venous thromboembolism) compared to 10 percent of patients who didn’t have ESA treatment.

Although the goal of ESAs was to reduce the need for blood transfusions, the percentage of transfusions remained steady at 22 percent each year from 1991 through 2002.  Overall survival didn’t differ between the patients who received ESAs and those who didn’t.

Chemotherapy can cause anemia when the bone marrow doesn’t keep up with the need to replace normally lost red blood cells. Erythropoiesis-stimulating agents such as Procrit® and Epogen® (epoetin alfa) and Aranesp® (darbepoetin alfa) stimulate the bone marrow to produce new red blood cells.  Ideally, use of ESAs should reduce the need for blood transfusions during chemo.

However, when researchers reviewed data in the Surveillance, Epidemiology, and End Results (SEER)–Medicare database for patients who were diagnosed with colon, lung, or breast cancer or with lymphoma from January 1991, through December 2002 and who received chemotherapy, they found no difference in blood transfusion rates.

They did find more blood clots, both in deep leg veins and in the lungs, among those who were treated with ESAs.  The rate of venous thromboembolism was 14.3 percent in the ESA patients and 9.8 percent in patients who didn’t get ESAs.

After FDA approval of ESAs, their use increased rapidly.  In 1991, 4.8 percent of patients got an ESA, but by 1992 nearly half of all chemotherapy patients in the SEER-Medicare database (45.9 percent) received ESA treatment.

Writing in the Journal of the National Cancer Institute, Dawn L. Hershman, MD, and her colleagues concluded,

Use of erythropoiesis-stimulating agent increased rapidly after its approval in 1991, but the blood transfusion rate did not change. Use of erythropoiesis-stimulating agents was associated with an increased risk of venous thromboembolism but not of mortality.

The FDA-approved label for Aranesp, Epogen, and Procrit limit their use to patients with anemia who are receiving chemotherapy.  They are not appropriate for anemic cancer patients not on chemo or for cancer patients whose treatment goal is cure.  A Medication Guide has been developed to help patients discuss the use of ESAs with their doctors.

SOURCE: Hershman et al., Journal of the National Cancer Institute, Advance Access online November 10, 2009.

Disclosure: C3 has accepted funding for projects and educational programs from Amgen in the form of unrestricted educational grants. C3 has ultimate authority over website content.

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