Erythropoietin Linked to More Severe Thrombocytopenia in Patients Treated for He

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Erythropoietin Linked to More Severe Thrombocytopenia in Patients

Treated for Hepatitis C

Low blood cell counts are a potential side effect of treatment for

chronic hepatitis C. Ribavirin can cause red blood cell destruction,

while interferon lowers levels of white blood cells and thrombocytes

(platelets; cell fragments responsible for blood clotting).

Diminished blood cell counts often necessitate dose reduction or

discontinuation of therapy.

Erythropoietin (EPO; Procrit) stimulates the production of both red

blood cells and thrombocytes. As reported in the October 2006

American Journal of Gastroenterology, researchers at the University

of Vienna in Austria conducted a study to investigate whether EPO can

help alleviate thrombocytopenia caused by pegylated interferon. The

authors hypothesized that EPO increases platelet reactivity and

protease activated receptor 1 (PAR-1) expression during combination

antiviral therapy.

In a placebo-controlled, double-blinded trial, 40 patients with

chronic hepatitis C were randomly assigned to receive either 10,000

IU EPO 3 times weekly or else placebo for 4 weeks in combination with

pegylated interferon alpha-2a (Pegasys) plus ribavirin.

Results

EPO alleviated the decrease in hemoglobin (a marker of anemia)

during combination antiviral therapy with ribavirin (10% vs 20%; P <

0.0001). Platelet counts decreased more in the EPO arm compared with

the placebo group on Day 28 (P = 0.007).

EPO induced a 40% increase in PAR-1 (P < 0.0001), which was

accompanied by a 100% increase in platelet reactivity (P < 0.0001).

PFA-100 platelet plug formation time and Pegasys-induced increase in

von Willebrand factor (a protein involved in clotting) did not differ

in the 2 study arms.

Conclusion

" Treatment with EPO alleviated the decrease in hemoglobin but

worsened [Pegasys-] induced thrombocytopenia after the first 4 weeks

of combination therapy, " the researchers wrote. " EPO caused PAR-1

receptor up-regulation on platelets, which promoted an increase in

platelet reactivity without affecting PFA-100 platelet plug formation

time. "

They concluded that, " EPO is not a useful option for short-term

support of platelet production during antiviral therapy. "

10/24/06